Improving throttle response and 'revvyness' on a YB engine- Ideas please
16-08-2013, 01:16 PM
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Improving throttle response and 'revvyness' on a YB engine- Ideas please
As title really.
My pretty standard YB on a L6 and Stg1 chip, while boosting at low rpm like you'd expect on the 4x4 Saff T3 and manifold it's on, feels SO dead and unresponsive it's daft really. And feels heavy and unwilling to rev, despite actually being fast (I wouldn't say it's actually down on power for the spec).
My other car, another 2ltr turbo, albeit much shorter stroke, has a turbo literally twice the size (good for ~550-600bhp and isn't on full boost for at least 1000rpm more than the Cossie one) but has a night and day difference in throttle response even off boost, and also how freely it revs. 7k in that feels less harsh than 4k from the YB. It's far nicer to drive, despite the much bigger turbo with the higher boost threshold.
SO, is there any way I can help the YB rev more freely, and more importantly have better throttle response? As if so, I'm keen to do it!
Before people start replying, please note, when I'm talking about response, I don't mean boost threshold (ie when the turbo boosts), as it boosts at low rpm anyhow, I really do mean throttle response (even off boost), and how quickly the turbo responds to putting my foot down (lag), whatever.
The 'Revvynes' issue, for want of a better word. Well, a lightweight flywheel is the only thing I can think of, as a Cossie flywheel is pretty fooking heavy, right? Gearing-wise it's geared to just over 170 (real speed) at 7500rpm, so I don't want it any shorter, and that's about the same, if not shorter, than my other car.
My first thoughts for the shitty response is the L6 and random ancient Stg1 Chip.
If I remember rightly on my old Cossie, changing from L6 to L8 seemed to wake the car up hugely, much more responsive, probably due to having a TPS that picked up more throttle positions than the L6 one does.
Aside from the above though, and things like ALS of course, any ideas?
Cheers!
My pretty standard YB on a L6 and Stg1 chip, while boosting at low rpm like you'd expect on the 4x4 Saff T3 and manifold it's on, feels SO dead and unresponsive it's daft really. And feels heavy and unwilling to rev, despite actually being fast (I wouldn't say it's actually down on power for the spec).
My other car, another 2ltr turbo, albeit much shorter stroke, has a turbo literally twice the size (good for ~550-600bhp and isn't on full boost for at least 1000rpm more than the Cossie one) but has a night and day difference in throttle response even off boost, and also how freely it revs. 7k in that feels less harsh than 4k from the YB. It's far nicer to drive, despite the much bigger turbo with the higher boost threshold.
SO, is there any way I can help the YB rev more freely, and more importantly have better throttle response? As if so, I'm keen to do it!
Before people start replying, please note, when I'm talking about response, I don't mean boost threshold (ie when the turbo boosts), as it boosts at low rpm anyhow, I really do mean throttle response (even off boost), and how quickly the turbo responds to putting my foot down (lag), whatever.
The 'Revvynes' issue, for want of a better word. Well, a lightweight flywheel is the only thing I can think of, as a Cossie flywheel is pretty fooking heavy, right? Gearing-wise it's geared to just over 170 (real speed) at 7500rpm, so I don't want it any shorter, and that's about the same, if not shorter, than my other car.
My first thoughts for the shitty response is the L6 and random ancient Stg1 Chip.
If I remember rightly on my old Cossie, changing from L6 to L8 seemed to wake the car up hugely, much more responsive, probably due to having a TPS that picked up more throttle positions than the L6 one does.
Aside from the above though, and things like ALS of course, any ideas?
Cheers!
16-08-2013, 02:52 PM
#2
I have similar thoughts on my car , obviously compared to more modern cars they are lazy etc but bad off boost performance is such a horrible trate to the point it can ruin the experience.
A good setup maybe in order? On stg1 myself with a setup changed the car significantly in response and driveability.
A good setup maybe in order? On stg1 myself with a setup changed the car significantly in response and driveability.
16-08-2013, 03:18 PM
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Well that's the thing, aside from the half a point difference in compression ratio (which to be fair should be made up for by the longer stroke of the YB), there's no inbuilt reason to the engine design that should make the YB feel lazy and unresponsive compared to the other engine.
Which makes me wonder, as mentioned, if it's the old L6 ECU/TPS etc, and the heavy ass YB flywheel.
The flywheel will prob help the lack of revvyness I mentioned. I mean on boost it's never going to rev as freely as it's less powerful than the other engine, but in general, off boost, part throttle, etc, even out of gear, it's much less willing to rev.
Confusing really, as the difference is absolutely massive, despite the YB having the turbo that boosts sooner. As you say, it ruins the experience when you drive them back to back. At the same power level the YB would be ten times more fun if it wasn't for this.
I honestly don't think it's a YB engine thing, I think it's something that can be sorted. Not 100% how though, hopefully someone does. The rally guys etc might be the best to know as it's the things they'd want for rallying.
Which makes me wonder, as mentioned, if it's the old L6 ECU/TPS etc, and the heavy ass YB flywheel.
The flywheel will prob help the lack of revvyness I mentioned. I mean on boost it's never going to rev as freely as it's less powerful than the other engine, but in general, off boost, part throttle, etc, even out of gear, it's much less willing to rev.
Confusing really, as the difference is absolutely massive, despite the YB having the turbo that boosts sooner. As you say, it ruins the experience when you drive them back to back. At the same power level the YB would be ten times more fun if it wasn't for this.
I honestly don't think it's a YB engine thing, I think it's something that can be sorted. Not 100% how though, hopefully someone does. The rally guys etc might be the best to know as it's the things they'd want for rallying.
Last edited by WTF?!; 16-08-2013 at 03:22 PM.
16-08-2013, 03:30 PM
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16-08-2013, 04:02 PM
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Another thing about the lack of response even off boost- The YB engine is in a car about 400kg lighter than the other engine I mentioned, so it's not even a weight thing.
I'm fairly convinced it's the L6 and heavy flywheel, but I'd like others opinions still.
The car is running 3in straight thru pipe from turbo back, no boxes.
I'm fairly convinced it's the L6 and heavy flywheel, but I'd like others opinions still.
The car is running 3in straight thru pipe from turbo back, no boxes.
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16-08-2013, 04:08 PM
#8
Your car has been downgraded, as it should have an L8 
, but no this won't make any difference!
The TPS makes no difference what so ever, the L8 has double the memory though, so it can support things such as ALS,LC,CL etc.
They are just typical of any other FI car of the era, even when I drive run of the mill cars, I find they are more responsive.
Yes, I seem to remember the 4x4 flywheel is lighter than the 2WD though, something like 7-8KG from memory, for the 4x4, this will improve the throttle response, but on the downside it looses you torque!
Plus remember, the internals are forged and so have a fair old mass to them, opposed to whatever your other car is which most likely are light!
Also another aspect in the said compresion ratio, modern FI cars are higher compression, which will make them more responsive off boost.
Martin
, but no this won't make any difference!The TPS makes no difference what so ever, the L8 has double the memory though, so it can support things such as ALS,LC,CL etc.
They are just typical of any other FI car of the era, even when I drive run of the mill cars, I find they are more responsive.
Yes, I seem to remember the 4x4 flywheel is lighter than the 2WD though, something like 7-8KG from memory, for the 4x4, this will improve the throttle response, but on the downside it looses you torque!
Plus remember, the internals are forged and so have a fair old mass to them, opposed to whatever your other car is which most likely are light!
Also another aspect in the said compresion ratio, modern FI cars are higher compression, which will make them more responsive off boost.
Martin
16-08-2013, 04:19 PM
#9
As standard they are a very numb off boost engine.
A good specialist can sort that out to the best available adjustments, adjusting valve timing and ignition timing to suit your needs can have great effect, though needs to be a specialist to take full advantage. or just put a decent compression ratio
in it. lol .
A good specialist can sort that out to the best available adjustments, adjusting valve timing and ignition timing to suit your needs can have great effect, though needs to be a specialist to take full advantage. or just put a decent compression ratio
in it. lol .
16-08-2013, 04:24 PM
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Not a downgrade, it just has a few upgrades.
It's a 2wd engine/box/diff/ecu/loom, but has a 4x4 manifold/turbo/intercooler fitted, that's all.
Regarding the L8 thing, well, 4wd TPS picks up every 1 degree throttle opening IIRC, but 2wd has, err, hardly any. Closed and open probably. lol.
Like said, all I do remember is on my old Cossie, when we swapped to an L8 setup from L6, with no other changes, the car had much better throttle response. No more power of course, but picked up nicer.
MAYBE this was due to a better map in the L8 compared to the chip in the L6 (neither were standard), but I really don't know.
Not sure what flywheel I have, presume 2wd, but if I remember right it's still heavy. The car weighs sub 1ton so it won't be a big issue.
The other engine is a 2ltr inline 6, so has much shorter stroke, but probably heavier internals to be honest as it's a much longer crank and 2 more pistons and rods.
The fact it's shorter stroke is deffo a reason why it feels revvier, I'd just like to do something to make the YB more like it- All I can think of is flywheel.
But the longer stroke of the YB I would have thought would make it have better intial throttle response.
And as mentioned, the compression ratio is only 8:1 on a YB compared to 8.6:1 on the other engine mentioned, not enough difference to really notice in my experience.
I've driven countless other Cossies over the years as well as my old one, but they were all highly tuned (and not on L6) compared to the engine I have now, so I can't really compare throttle response.
I really don't think the response thing is an engine design/problem thing at all. I dunno, but it's annoying really, as even the original slow as crap engine the car had before the YB engine swap is 10 times more perky and punchy at initial throttle tip-in, despite having no power or torque lol.
It's a 2wd engine/box/diff/ecu/loom, but has a 4x4 manifold/turbo/intercooler fitted, that's all.
Regarding the L8 thing, well, 4wd TPS picks up every 1 degree throttle opening IIRC, but 2wd has, err, hardly any. Closed and open probably. lol.
Like said, all I do remember is on my old Cossie, when we swapped to an L8 setup from L6, with no other changes, the car had much better throttle response. No more power of course, but picked up nicer.
MAYBE this was due to a better map in the L8 compared to the chip in the L6 (neither were standard), but I really don't know.
Not sure what flywheel I have, presume 2wd, but if I remember right it's still heavy. The car weighs sub 1ton so it won't be a big issue.
The other engine is a 2ltr inline 6, so has much shorter stroke, but probably heavier internals to be honest as it's a much longer crank and 2 more pistons and rods.
The fact it's shorter stroke is deffo a reason why it feels revvier, I'd just like to do something to make the YB more like it- All I can think of is flywheel.
But the longer stroke of the YB I would have thought would make it have better intial throttle response.
And as mentioned, the compression ratio is only 8:1 on a YB compared to 8.6:1 on the other engine mentioned, not enough difference to really notice in my experience.
I've driven countless other Cossies over the years as well as my old one, but they were all highly tuned (and not on L6) compared to the engine I have now, so I can't really compare throttle response.
I really don't think the response thing is an engine design/problem thing at all. I dunno, but it's annoying really, as even the original slow as crap engine the car had before the YB engine swap is 10 times more perky and punchy at initial throttle tip-in, despite having no power or torque lol.
Last edited by WTF?!; 16-08-2013 at 04:28 PM.
16-08-2013, 04:32 PM
#12
I was going on the basis that you mentioned it was a 4x4 saff.
Nope, the TPS only differs in that the 2WD (PF01) contains a switch, which is open circuit at idle, apart from that the design is the same.
You also said, in your inital post it's a 'random' chip which striaght away rings alarm bells.
Martin
Nope, the TPS only differs in that the 2WD (PF01) contains a switch, which is open circuit at idle, apart from that the design is the same.
You also said, in your inital post it's a 'random' chip which striaght away rings alarm bells.
Martin
16-08-2013, 06:08 PM
#16
Too many posts.. I need a life!!
2wd flywheel is lighter than 4x4 and makes a big difference, have you had you engine apart ? Was a bought engine if the answers are you don't really know then it may be low comped which is very lazy at revving a std comp engine is actually not ba at all and for you to notice it there must be some thing a miss, and comparing it to a totally for rent engine is utterly pointless it's a different engine simple so will behave different !
16-08-2013, 07:34 PM
#17
Definately get it calibrated/setup with a nice map and go from there would be my first shout.
Are you certain the cam timing and fueling is correct , my old engine was not optimum and once corrected made a huge difference in midrange throttle and generaly a much happier engine. They are known for not revving much as standard and this can be increased via the ecu of course. Evolution chips stg 3 + YBB is 7600 limiter for example iirc.
More modern ecu may also increase driveability but thats not to say the weber cant do it , A live map is the best way to go.
Are you certain the cam timing and fueling is correct , my old engine was not optimum and once corrected made a huge difference in midrange throttle and generaly a much happier engine. They are known for not revving much as standard and this can be increased via the ecu of course. Evolution chips stg 3 + YBB is 7600 limiter for example iirc.
More modern ecu may also increase driveability but thats not to say the weber cant do it , A live map is the best way to go.
Last edited by opposite lock; 16-08-2013 at 07:36 PM.
16-08-2013, 08:08 PM
#18
Would the shorter stroke not mave it rev faster simply because the crank/rods/pistons dont have to move as far, thus spinning faster? Thats the way i see it anyway lol
I think the fact the RB20 has 2 extra cylinders will make a massive difference to response.
What size is the throttle body on the RB and on the YB?
You could always just build another RB to the same spec and stick that in the MX5 lol
I think the fact the RB20 has 2 extra cylinders will make a massive difference to response.
What size is the throttle body on the RB and on the YB?
You could always just build another RB to the same spec and stick that in the MX5 lol
16-08-2013, 08:33 PM
#19
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Most modern cars are drive by wire systems so will be intant on the throttle, plus they have a map for each gear to get the best performance per change.
16-08-2013, 09:37 PM
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Some people need to read threads before replying, and maybe learnt the difference between lag and boost threshold too
Yes it drives 'perfect' off boost, but compared to pretty much every other 2ltr turbo engine, Impreza, Evo, RB20, SR20, etc etc, it feels a bit dead on initial throttle response, esp at lower rpm.
My boost comes in 2000-2500rpm too, that's not lag, that's boost threshold.
Nothing to do with drive by wire at all, none of the engines mentioned have it.
It's not low comp etc etc, it's a bog stock 2wd engine. TBH low comp engines lack off boost power, but it doesn't really affect throttle response much anyhow.
Cam timing is correct, fueling is fine, all checked.
The old/unknown Stg1 chip might just be shite, could have retarded ign across the board or something for all I know.
Fudgey- Pretty much same size TB, but it wouldn't make much difference unless one was overly big so light throttle was more like full.
I got all the L8/greens/3bar/TPS stuff to go on it, I'll take it to Will and get it stg 3'd and L8'd along with coilpack and ALS and hope that sorts it as nobody has any real suggestions barring what I already thought.
Soon as clutch/box dies I'll go flywheel too as I know that will help.
Yes it drives 'perfect' off boost, but compared to pretty much every other 2ltr turbo engine, Impreza, Evo, RB20, SR20, etc etc, it feels a bit dead on initial throttle response, esp at lower rpm.
My boost comes in 2000-2500rpm too, that's not lag, that's boost threshold.
Nothing to do with drive by wire at all, none of the engines mentioned have it.
It's not low comp etc etc, it's a bog stock 2wd engine. TBH low comp engines lack off boost power, but it doesn't really affect throttle response much anyhow.
Cam timing is correct, fueling is fine, all checked.
The old/unknown Stg1 chip might just be shite, could have retarded ign across the board or something for all I know.
Fudgey- Pretty much same size TB, but it wouldn't make much difference unless one was overly big so light throttle was more like full.
I got all the L8/greens/3bar/TPS stuff to go on it, I'll take it to Will and get it stg 3'd and L8'd along with coilpack and ALS and hope that sorts it as nobody has any real suggestions barring what I already thought.
Soon as clutch/box dies I'll go flywheel too as I know that will help.
17-08-2013, 12:46 AM
#21
Too many posts.. I need a life!!
Like I said you can't compare a std yb engine to another 2.0 ltr turbo engine , for starter an impreza is a boxer engine utterly worlds apart and they have a higher comp ratio and the evo even higher comp ratio again , and I've never heard of anyone complain if poor response etc like what your complaint of so rather than try to improve things just fix the problem and enjoy the yb for what it is
17-08-2013, 07:00 AM
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It's easier to move 6 small pistons than 4 larger ones...yb's are one of the best when on boost...so get it on boost and keep calm��
Maybe a different turbo that spools easier would help?
Comparing engines on the basis that they are 2.0litre is not the best gauge...
Good luck,hope you get it sorted��
Maybe a different turbo that spools easier would help?
Comparing engines on the basis that they are 2.0litre is not the best gauge...
Good luck,hope you get it sorted��
17-08-2013, 09:45 AM
#24
OP has your car been setup recently? If the chip is unknown switch it for an off the shelf calibrated to spec version stg1 and see if you get a difference.
My l6 does have a miss/hesitant point @1600 rpm 2which improved after a setup but didnt cure it completely.
also i do have a small black sootyness around the exhaust primary part , its minimal but annoying and I sometimes wonder if this could cause a small 'glitch' in small throttle slow driving.
A live map for any setup surely though is required to get the very best from what you have.
My l6 does have a miss/hesitant point @1600 rpm 2which improved after a setup but didnt cure it completely.
also i do have a small black sootyness around the exhaust primary part , its minimal but annoying and I sometimes wonder if this could cause a small 'glitch' in small throttle slow driving.
A live map for any setup surely though is required to get the very best from what you have.
17-08-2013, 10:08 AM
#26
PassionFord Regular
The compression from 8:1 to 8.6:1 would make loads of difference, people complain how the responsiveness is shit with low comp and with the low comp engines people were going down to 7.6:1, that is only 0.4 difference where as 8.6:1 would be 0.6 difference
Also do you have adjustable pulleys?? cam/valve overlap will make a difference, just because all your markers are lined up doesn't mean this is the best your engine will run things can still be tweaked, ignition timings etc.
Also do you have adjustable pulleys?? cam/valve overlap will make a difference, just because all your markers are lined up doesn't mean this is the best your engine will run things can still be tweaked, ignition timings etc.
17-08-2013, 10:20 AM
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As I said, it's nothing to do with what rpm it spools at, it's on a stock Saff 4x4 T3, my other car hasn't got full boost till well over 1000rpm later, that's not an issue.
Stock pullies, and in my experience of owning quite a lot of low comp engines, if the mapping is right, while it might lose a bit of off boost power, response etc isn't really affected.
When it comes down to it, the majority of Impreza turbo engines left the factory at just 8:1, same as YBs- It's not really low.
Yeah, you've said it twice, but that doesn't make it right lol.
Most Impreza engines made were 8:1 compression, same as YBs, for a start.
Compression ratio and throttle response aren't really that related, owned and driven enough cars of massively different compression ratios to say that, hence why I said I'm 99% sure it's nothing to do with 'its just a YB', I think it's probably setup related.
TBH you don't hear most people complain as they seem to be YB or nothing so know no different. Yet over the last 15odd years of being around Cossies all I ever do is defend peoples comments (most of which are people who've driven em) who say they suck ball off boost with no response.
You know, that's actually good advice, glad someone has some. I don't know, I'll check, cheers! :thumbs:
The compression from 8:1 to 8.6:1 would make loads of difference, people complain how the responsiveness is shit with low comp and with the low comp engines people were going down to 7.6:1, that is only 0.4 difference where as 8.6:1 would be 0.6 difference
Also do you have adjustable pulleys?? cam/valve overlap will make a difference, just because all your markers are lined up doesn't mean this is the best your engine will run things can still be tweaked, ignition timings etc.
Also do you have adjustable pulleys?? cam/valve overlap will make a difference, just because all your markers are lined up doesn't mean this is the best your engine will run things can still be tweaked, ignition timings etc.
When it comes down to it, the majority of Impreza turbo engines left the factory at just 8:1, same as YBs- It's not really low.
Most Impreza engines made were 8:1 compression, same as YBs, for a start.
Compression ratio and throttle response aren't really that related, owned and driven enough cars of massively different compression ratios to say that, hence why I said I'm 99% sure it's nothing to do with 'its just a YB', I think it's probably setup related.
TBH you don't hear most people complain as they seem to be YB or nothing so know no different. Yet over the last 15odd years of being around Cossies all I ever do is defend peoples comments (most of which are people who've driven em) who say they suck ball off boost with no response.
You know, that's actually good advice, glad someone has some. I don't know, I'll check, cheers! :thumbs:
Last edited by WTF?!; 17-08-2013 at 10:22 AM.
17-08-2013, 10:28 AM
#28
Testing the future
if the measuring device you put on is analogue, i.e. an old school voltmeter with swinging needle, then you can measure that voltage as finely as the scale on the device. if you had a meter that was a kilometer wide and had a marking every 1mm you could measure it in 1 million 'sections', i.e. every 0.000005V
if the measuring device has an 8 bit analogue to digital converter like an old ecu does, that voltage, say 0 to 5V, can be measured in 2 to the power of 8 'sections', i.e. 256 sections, or every 0.02V
a more modern ecu would probably have a 16 bit ADC and could measure that 5V in 65536 sections, i.e. every 0.00008V.
however, none of that would really matter if you only had a map in the ecu that had 2 break points in it at 0V and 5V.
17-08-2013, 10:50 AM
#29
PassionFord Regular
This information was taken from rallycars.com, found this while I was looking in to engine geometry
"The YB series of Cosworth engines are "super square", short stroke i.e. bore is greater than stroke (90,8 x 77,0 mm in this case) thus advantaging high rev output rather than low end torque as is the case in long stroke engines. It's a fact that all Cosworth engines, even heavily modified ones, require to be operated in relatively high revs in order to be responsive"
And this taken from Iskycams
"Lengthening of valve timing in the gasoline engine brought on accidental overlapping of the intake and exhaust valve events. (Both intake and exhaust valves are slightly open at T.D.C.
In the early days, this unintentional overlapping was at first considered detrimental. But much later, it was discovered that a mild scavenging effect was obtained from the overlap event when the exhaust actually pulled some of the intake charge in"
Adjusting how the cams over lap cam make a huge difference to how the car drives, this is a quote from J1mbo in a thread I was asking about engine stroking
"My own engine spent a week on the dyno playing with cams and I could vary torque from 450 to 490lbft of torque just with timing
I settled at 470lbft and 552bhp as 2wd I didn't want too aggresive and wanted a wide power band"
If you want any of the links to read the full articles I'll happily find and post them
"The YB series of Cosworth engines are "super square", short stroke i.e. bore is greater than stroke (90,8 x 77,0 mm in this case) thus advantaging high rev output rather than low end torque as is the case in long stroke engines. It's a fact that all Cosworth engines, even heavily modified ones, require to be operated in relatively high revs in order to be responsive"
And this taken from Iskycams
"Lengthening of valve timing in the gasoline engine brought on accidental overlapping of the intake and exhaust valve events. (Both intake and exhaust valves are slightly open at T.D.C.
In the early days, this unintentional overlapping was at first considered detrimental. But much later, it was discovered that a mild scavenging effect was obtained from the overlap event when the exhaust actually pulled some of the intake charge in"
Adjusting how the cams over lap cam make a huge difference to how the car drives, this is a quote from J1mbo in a thread I was asking about engine stroking
"My own engine spent a week on the dyno playing with cams and I could vary torque from 450 to 490lbft of torque just with timing
I settled at 470lbft and 552bhp as 2wd I didn't want too aggresive and wanted a wide power band"
If you want any of the links to read the full articles I'll happily find and post them
17-08-2013, 11:31 AM
#30
Too many posts.. I need a life!!
I know the feeling you describe, they felt Like that when they were new and still have that feeling in various states of tune I've had them in so I think it's just a characteristic of the YB.
17-08-2013, 01:10 PM
#31
............
Deffo the compression ratio, remember its not as simple as saying it's 8.1 and my imprezza is 8.1 so should be the same
Dynamic compression ratio is affected by many things, Stu has done some great articles on it
Dynamic compression ratio is affected by many things, Stu has done some great articles on it
17-08-2013, 03:45 PM
#32
For low end response the YB is a poor engine both geometrically (bore and stroke) and mechanically (Inertia of components) I'm afraid.
The huge and heavy flywheel doesn't help, nor does the very heavy bottom end.
The thing is just hugely over engineered for low states of tune and will never feel like a modern lightweight 4 pot that falls to pieces at 350ftlb of torque.
Advancing the cams to shift the engines efficiency lower can help significantly if your willing to run more boost up the top to overcome the VE drop or indeed don't care about BHP figures but ultimately, a responsive revy little engine she isn't.
That said, without driving your car I couldn't comment on how yours actually performs, and the usual responsiveness problem is normally exasperated significantly by bad states of tune, specifically very rich mixtures, poor cam timing and spark timing issues. Not a lot else I can add without access to the car itself.
The huge and heavy flywheel doesn't help, nor does the very heavy bottom end.
The thing is just hugely over engineered for low states of tune and will never feel like a modern lightweight 4 pot that falls to pieces at 350ftlb of torque.
Advancing the cams to shift the engines efficiency lower can help significantly if your willing to run more boost up the top to overcome the VE drop or indeed don't care about BHP figures but ultimately, a responsive revy little engine she isn't.
That said, without driving your car I couldn't comment on how yours actually performs, and the usual responsiveness problem is normally exasperated significantly by bad states of tune, specifically very rich mixtures, poor cam timing and spark timing issues. Not a lot else I can add without access to the car itself.
Last edited by Stu @ M Developments; 17-08-2013 at 03:46 PM.
19-08-2013, 03:06 PM
#34
PassionFord Regular
19-08-2013, 11:03 PM
#38
PassionFord Post Whore!!
I think the light flywheel = less torque statement is rubbish/internet myth/old wives tale.
I have an alloy flywheel on my car and lightened stock flywheels on other cars and did not notice a lack of torque at all.
I have an alloy flywheel on my car and lightened stock flywheels on other cars and did not notice a lack of torque at all.
20-08-2013, 10:48 AM
#39
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For low end response the YB is a poor engine both geometrically (bore and stroke) and mechanically (Inertia of components) I'm afraid.
The huge and heavy flywheel doesn't help, nor does the very heavy bottom end.
The thing is just hugely over engineered for low states of tune and will never feel like a modern lightweight 4 pot that falls to pieces at 350ftlb of torque.
Advancing the cams to shift the engines efficiency lower can help significantly if your willing to run more boost up the top to overcome the VE drop or indeed don't care about BHP figures but ultimately, a responsive revy little engine she isn't.
That said, without driving your car I couldn't comment on how yours actually performs, and the usual responsiveness problem is normally exasperated significantly by bad states of tune, specifically very rich mixtures, poor cam timing and spark timing issues. Not a lot else I can add without access to the car itself.
The huge and heavy flywheel doesn't help, nor does the very heavy bottom end.
The thing is just hugely over engineered for low states of tune and will never feel like a modern lightweight 4 pot that falls to pieces at 350ftlb of torque.
Advancing the cams to shift the engines efficiency lower can help significantly if your willing to run more boost up the top to overcome the VE drop or indeed don't care about BHP figures but ultimately, a responsive revy little engine she isn't.
That said, without driving your car I couldn't comment on how yours actually performs, and the usual responsiveness problem is normally exasperated significantly by bad states of tune, specifically very rich mixtures, poor cam timing and spark timing issues. Not a lot else I can add without access to the car itself.
I wouldn't be surprised, as I 'think' the Stg1 Chip in the ECU is at least 15 years old, if the ign was just knocked back, and the fuel increased, right across the board, hence the extra power but feels unresponsive and numb.
Got 99% of the bits needed to go Greens/L8/Coilpack/etc etc anyhow, so a new chip/map/whatever then should work a treat.
And whenever the clutch dies then I'll get a flywheel on it too. The Opplinger ones seem to be the lightest I've seen for the stock sized clutch, I think?
20-08-2013, 12:22 PM
#40
More accurately, due to the lighter mass it has less energy for the same speed, therefore less torque will be applied, for example in between gear changes the revs will drop further/quicker.
Imo it's probably only noticeable if you have a big difference in weight.
Martin