GT3071 Turbo @ 2.4bar on a YB engine gives 514BHP!
20-10-2010, 09:38 AM
#1
GT3071 Turbo @ 2.4bar on a YB engine gives 514BHP!
Absolutely epic results here for one of Doug Stirlings escort cosworths!
Background was that it was a bit of an evolved spec over time, it had an NMS head and NMS cams on a Dave Pitchard built bottom end running on L8 and mapped by NMS on a GT3076 turbo on a .63 housing, made respectable power but Doug felt it was too laggy (TBH it wasnt *that* bad IMHO, you just needed to keep the revs up when driving it and it went well, and was still a massive leap forward from the old T4 it had before that anyway!).
Doug took it to Mark Shead at MAD and gave him carte blanche to change anything that he felt was appropriate with the aim of not losing top end power but gaining spool and responsiveness as that is what Doug is really into with his cars. Power before was tested at 480bhp IIRC (will try and get the graph off doug when I see him next or see if he can email me it)
Mark removed the water injection, ditched the cams in favour of some of his, fitted one of this new spec-r intercoolers and fitted a vipec ECU and remapped it with a GT3071.82 instead of a GT3076.63
Not only has it massively transformed the bottom end torque (at one point in the rev range IIRC it made 190lbft more than previous due to the earlier spool) its also gained power on top as well:
Here is the graph how it stands now:
It ties in now finally with how much power MAD get from the same turbo on an Evo engine as this is the first GT3071 they have done on a big spec head and latest specR intercooler, all their other 3071 conversions have been on more standard cars, giving around the 470bhp or so mark.
Interestingly Doug's engine is still low compression, 7.2:1 in fact, so the top end power could possibly edge up a little more form a raise in compression too.
Hopefully I'll get a chance to take it out for a spin on sunday if Doug has it with him when I see him, should be manic now on the 3.9 gearing as it felt pretty reasonable even before.
PS, when they tried edging the boost up to 2.7 bar, it made 522bhp and 520lb ft! but still tailed off to the same figures at the top end as the turbo just cant maintain the boost at high RPM as it really is flat out at that
Background was that it was a bit of an evolved spec over time, it had an NMS head and NMS cams on a Dave Pitchard built bottom end running on L8 and mapped by NMS on a GT3076 turbo on a .63 housing, made respectable power but Doug felt it was too laggy (TBH it wasnt *that* bad IMHO, you just needed to keep the revs up when driving it and it went well, and was still a massive leap forward from the old T4 it had before that anyway!).
Doug took it to Mark Shead at MAD and gave him carte blanche to change anything that he felt was appropriate with the aim of not losing top end power but gaining spool and responsiveness as that is what Doug is really into with his cars. Power before was tested at 480bhp IIRC (will try and get the graph off doug when I see him next or see if he can email me it)
Mark removed the water injection, ditched the cams in favour of some of his, fitted one of this new spec-r intercoolers and fitted a vipec ECU and remapped it with a GT3071.82 instead of a GT3076.63
Not only has it massively transformed the bottom end torque (at one point in the rev range IIRC it made 190lbft more than previous due to the earlier spool) its also gained power on top as well:
Here is the graph how it stands now:
It ties in now finally with how much power MAD get from the same turbo on an Evo engine as this is the first GT3071 they have done on a big spec head and latest specR intercooler, all their other 3071 conversions have been on more standard cars, giving around the 470bhp or so mark.
Interestingly Doug's engine is still low compression, 7.2:1 in fact, so the top end power could possibly edge up a little more form a raise in compression too.
Hopefully I'll get a chance to take it out for a spin on sunday if Doug has it with him when I see him, should be manic now on the 3.9 gearing as it felt pretty reasonable even before.
PS, when they tried edging the boost up to 2.7 bar, it made 522bhp and 520lb ft! but still tailed off to the same figures at the top end as the turbo just cant maintain the boost at high RPM as it really is flat out at that
20-10-2010, 09:43 AM
#3
Some more spec from Doug:
Dave Pritchard built Engine, 2 litre Mahle pistons WRC h/gasket, 7.2:1 comp ratio, NMS flowed head, hydraulic lifters.
Siemens 900cc injectors
Small turbo plenum with 10mm spacer
MAD modifications:
Latest type Spec-R compact Garrett cored intercooler
NO water injection (removed from car)
Latest MAD GT-3071 spec turbo kit with free-flow exhaust elbow
Coil on plug
Vipec ECU
MAD loom
MAD cams
MAD mapped
Gearbox is Fix-It (ex YUM box), built by Bara Mortorsport. 60nM centre VC
Bara built Quaife ATB front & rear diffs, final drive is 3.9:1
ZOO Beam.
Compbrake TCA's
AP 330 / 4 pots front, Compbrake 300mm rear/standard callipers.
Toyo T1R tyres (extra load)
Dave Pritchard built Engine, 2 litre Mahle pistons WRC h/gasket, 7.2:1 comp ratio, NMS flowed head, hydraulic lifters.
Siemens 900cc injectors
Small turbo plenum with 10mm spacer
MAD modifications:
Latest type Spec-R compact Garrett cored intercooler
NO water injection (removed from car)
Latest MAD GT-3071 spec turbo kit with free-flow exhaust elbow
Coil on plug
Vipec ECU
MAD loom
MAD cams
MAD mapped
Gearbox is Fix-It (ex YUM box), built by Bara Mortorsport. 60nM centre VC
Bara built Quaife ATB front & rear diffs, final drive is 3.9:1
ZOO Beam.
Compbrake TCA's
AP 330 / 4 pots front, Compbrake 300mm rear/standard callipers.
Toyo T1R tyres (extra load)
20-10-2010, 09:51 AM
#6
The one difference between this turbo and yours that will effect top end power potentially is due to the headwork this one was tried WITHOUT the antisurge porting, where as yours has been ordered with it, and in theory the surge porting loses you a bit of top end (but is required on a more standard head to allow a decent amount of midrange boost)
20-10-2010, 09:57 AM
#7
Chip,
No one seems to know what my head has had done
We think it is the following:
The ports just smoothed, and the throats opened a small amount
So Mark said go for the ported shroud
We do know it wasn't really much that has been done when you consider what you can do
How much would it lose you top end do you think?
No one seems to know what my head has had done
We think it is the following:
The ports just smoothed, and the throats opened a small amount
So Mark said go for the ported shroud
We do know it wasn't really much that has been done when you consider what you can do
How much would it lose you top end do you think?
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20-10-2010, 10:20 AM
#13
Chip,
No one seems to know what my head has had done
We think it is the following:
The ports just smoothed, and the throats opened a small amount
So Mark said go for the ported shroud
We do know it wasn't really much that has been done when you consider what you can do
How much would it lose you top end do you think?
No one seems to know what my head has had done
We think it is the following:
The ports just smoothed, and the throats opened a small amount
So Mark said go for the ported shroud
We do know it wasn't really much that has been done when you consider what you can do
How much would it lose you top end do you think?
If you want a guess maybe 10bhp or so less for the ported one on the same engine, but that really is only a guess from seeing other ported versus non ported not that specific one.
There are 3 differences between this and Rich's which add up to 40 odd bhp difference:
Headwork
Non ported shroud
Better intercooler
I suspect the surgeporting is the smaller of the effects if anything.
20-10-2010, 10:36 AM
#15
That second graph really does show the difference, and quite bad really, moving from a 3076, down to a 3071 and that happening! Just goes to show, once you get it all right...
I have a hart inlet and will be getting the Spec-R cooler Chip, so maybe I'll sit halfway, who knows?
I have a hart inlet and will be getting the Spec-R cooler Chip, so maybe I'll sit halfway, who knows?
20-10-2010, 10:41 AM
#19
I have a hart inlet and will be getting the Spec-R cooler Chip, so maybe I'll sit halfway, who knows?
20-10-2010, 10:45 AM
#22
I've found that life I needed.. It's HERE!!
Looks like there were improvements to be made with the 3076 setup if it 'only' made 480odd.
The way it comes on power now looks pretty brutal. Is such a steep climb such a good thing?
The way it comes on power now looks pretty brutal. Is such a steep climb such a good thing?
20-10-2010, 10:51 AM
#23
As i mentioned it was a bit of an evolved spec, so Im not sure how much say Karl really had in its totality, for example I dont know if it was Doug that choose the .63 housing on the 3076 to cut down lag or Karl, and the .63 is proven to be a bad combination on the GT30s IME, so if that was a decision Doug made and Karl had to map around it for example then it wouldnt really be fair to say the results reflected on Karl etc
So I am sure that this didnt represent Karl at the top of his game.
Anyway, I really dont want an NMS vs MSD thread as personally Ive got a lot of respect for both of them anyway.
Doug's on marks latest cams, which is for both of them, so you arent quite on the same as him I believe.
Its possible to run a 3076 on internal gate as well, although not common.
So I am sure that this didnt represent Karl at the top of his game.
Anyway, I really dont want an NMS vs MSD thread as personally Ive got a lot of respect for both of them anyway.
Yes got the same inlet cam as Rich, std exhaust cam 
D'oh of course Doug would have already been external wastegate on the 3076 
20-10-2010, 10:54 AM
#25
The way it comes on power now looks pretty brutal. Is such a steep climb such a good thing?
For a rwd trackday car I would agree that this is far too brutal, but for 3rd gear in a straight line in a 4wd escort its awesome for putting a big grin on your face I should think, especially on the short gearing (I'll let you know when ive driven it, lol)
20-10-2010, 10:55 AM
#26
Mark can no doubt get the rolling road to come up with it though.
The old turbo was holding on to boost better at the top end too IIRC, this one tails off down to 1.9 bar at the top from what Doug was saying.
20-10-2010, 11:02 AM
#28
It was 2.4 bar before, and 2.7 bar after, but I dont have that on a graph.
Mark can no doubt get the rolling road to come up with it though.
The old turbo was holding on to boost better at the top end too IIRC, this one tails off down to 1.9 bar at the top from what Doug was saying.
Mark can no doubt get the rolling road to come up with it though.
The old turbo was holding on to boost better at the top end too IIRC, this one tails off down to 1.9 bar at the top from what Doug was saying.
The tags have started!!
Last edited by Martin-Hadland; 20-10-2010 at 11:05 AM.
20-10-2010, 11:10 AM
#31
Thought you were genuinely interested rather than playing stupid games TBH.
I dont have the graph that you are asking for so cant post it yet where as obviously as its your rollers you can get the franco one very easily, but feel free to be a knob if you want to about it
I dont have the graph that you are asking for so cant post it yet where as obviously as its your rollers you can get the franco one very easily, but feel free to be a knob if you want to about it
Last edited by Chip; 20-10-2010 at 11:16 AM.
20-10-2010, 11:23 AM
#36
Im sure if he was on a twin scroll primary designs manifold or similar, it would have remained, or more likely it would have been used with a 3076, as the twinscroll helps them spool.
When I said Doug gave Mark carte blanche, it didnt extend quite that far
20-10-2010, 11:24 AM
#38
Not sure with the latest trick roller bearing T4's as only really seen them used on a stroker YB which doesnt really compare, but compared to a "normal" T4, its massively more responsive, the old T4 engine was fucking horrible really!
