Best road going spec based on a GT30
#46
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Originally Posted by pete mcrash
is it not just how different engines are designed..????
#47
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Originally Posted by MD Cos
got a mate who's gt4 runs a gt3076r and 8.5:1... and he's thinking of making it higher comp! had no problems whatsoever so far at 1.1 bar
Originally Posted by Red16
the jap lads all seem to run around 8.5:1 generally.
And a LOT of people bullshit about what comp a car is. I know for a fact some big name Skyline tuners run comp in the mid 7s and keep it quiet or blatantly lie.
And standard compression pistons DONT always mean standard compression
And you can run more boost, but less ign, and ign generally gives more power than boost after a certain level.
And you can also get away with more with wilder cams, more headwork, and bigger exhaust housings.
And all that lot is exactly why engines need to be specced as a whole, as pic some bits of a low comp engine, and some of a high, and you will end up with a properly shit engine.
#48
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Originally Posted by Stavros
Originally Posted by MD Cos
got a mate who's gt4 runs a gt3076r and 8.5:1... and he's thinking of making it higher comp! had no problems whatsoever so far at 1.1 bar
Originally Posted by Red16
the jap lads all seem to run around 8.5:1 generally.
And a LOT of people bullshit about what comp a car is. I know for a fact some big name Skyline tuners run comp in the mid 7s and keep it quiet or blatantly lie.
And standard compression pistons DONT always mean standard compression
And you can run more boost, but less ign, and ign generally gives more power than boost after a certain level.
And you can also get away with more with wilder cams, more headwork, and bigger exhaust housings.
And all that lot is exactly why engines need to be specced as a whole, as pic some bits of a low comp engine, and some of a high, and you will end up with a properly shit engine.
Mark
#50
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but 8.5:1 compression pistons should mean 8.5:1 comp pistons surely!
i know what youre saying Stavros but theyres just far too many jap cars (more than a few on the MLR) running this kind of c/r with say 1.5-2bar boost on pump fuel, they cant all be lying.
Edited to say - isn't Gary@APT running 1.8bar and 8.5:1 with fantastic results?
i know what youre saying Stavros but theyres just far too many jap cars (more than a few on the MLR) running this kind of c/r with say 1.5-2bar boost on pump fuel, they cant all be lying.
Edited to say - isn't Gary@APT running 1.8bar and 8.5:1 with fantastic results?
#53
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Originally Posted by _DAN_
Originally Posted by Red16
but 8.5:1 compression pistons should mean 8.5:1 comp pistons surely!
Doesn't the skim of the head change the situation there?
#54
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Originally Posted by Red16
but 8.5:1 compression pistons should mean 8.5:1 comp pistons surely!
And yeah, im not saying they all lying, they not, not even a majority of them, im just giving the various reasons.
Also engine/head/piston design plays a part, just like the cams/turbo/etc i already mentioned.
Skyline GTR engines, and maybe Evos too, can run a shocking amount of ignition compared to what cossies seem to be able to.
Infact GTR engine it seems, if ran at ign numbers you would normally consider normal and safe, are shite and run dissapointing numbers.
There more than one way to do anything.
#55
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Originally Posted by Stavros
Enlarged combustion chambers
Originally Posted by Stavros
Skyline GTR engines, and maybe Evos too, can run a shocking amount of ignition compared to what cossies seem to be able to.
Infact GTR engine it seems, if ran at ign numbers you would normally consider normal and safe, are shite and run dissapointing numbers.
There more than one way to do anything.
Infact GTR engine it seems, if ran at ign numbers you would normally consider normal and safe, are shite and run dissapointing numbers.
There more than one way to do anything.
#56
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Originally Posted by rapidcossie
The comp ratio on my car is so low that people on here would say it must be shit, yet is one of the most powerful and responsive like for like.
#58
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Originally Posted by NEIL A
Originally Posted by rapidcossie
The comp ratio on my car is so low that people on here would say it must be shit, yet is one of the most powerful and responsive like for like.
#59
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Originally Posted by Red16
Originally Posted by Mike Rainbird
I wouldn't run high compression on a car that is going to be regularly maxed out or see track days UNLESS you have the budget to run suitable fuel at these events.
everytime i see a cossie spec its always got low comp, between 6.8 and 7.*:1 whereas the jap lads all seem to run around 8.5:1 generally.
What difference does it make if theyre both ran on say Shell V-Power? How come it works on Evo's etc but not on cossies, even though they both run decent boost levels?
I understand the theory behind detonation but the 8.5:1 compression doesnt seem to cause any problems over on the darkside, but scares the shit out of the ford boys
#61
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We do this topic every 6 months, all we ever get is Sheady going 8.1-15.1 , Rainbum going anything over 8.1 is a timebomb , and lots of from people, why even bother replying if you are not going to tell us what you are running?
Talk about secret squirrel
On a different tack, I will be running a CR Engineering T38 on my escort cos, looking for anything around 420BHP, but I was hoping for a nice fat midrange but I am a bit worried now . Engine will be 7.4:1 (cc'd) , with a std exhaust cam and a BD14 inlet, with mild headwork, having spoke to my tuner I have every confidence his prediction of not a lot more lag than a .48 T34 will be true, as the engine has been specced with this turbo in mind. If I don't like it I might be forced to try a GT30
I also have a GT35 sat under my bench, now a few people have swapped back to the GT30 from this, is the general opinion that a GT35 is a bit too big for a 2.0 YB to be nice to drive on the road?
Talk about secret squirrel
On a different tack, I will be running a CR Engineering T38 on my escort cos, looking for anything around 420BHP, but I was hoping for a nice fat midrange but I am a bit worried now . Engine will be 7.4:1 (cc'd) , with a std exhaust cam and a BD14 inlet, with mild headwork, having spoke to my tuner I have every confidence his prediction of not a lot more lag than a .48 T34 will be true, as the engine has been specced with this turbo in mind. If I don't like it I might be forced to try a GT30
I also have a GT35 sat under my bench, now a few people have swapped back to the GT30 from this, is the general opinion that a GT35 is a bit too big for a 2.0 YB to be nice to drive on the road?
#62
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Originally Posted by RWD_cossie_wil
We do this topic every 6 months, all we ever get is Sheady going 8.1-15.1 , Rainbum going anything over 8.1 is a timebomb , and lots of from people, why even bother replying if you are not going to tell us what you are running?
Talk about secret squirrel
Talk about secret squirrel
QUOTE OF THE MONTH!
#63
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Originally Posted by RWD_cossie_wil
We do this topic every 6 months, all we ever get is Sheady going 8.1-15.1 , Rainbum going anything over 8.1 is a timebomb , and lots of from people, why even bother replying if you are not going to tell us what you are running?
Talk about secret squirrel
On a different tack, I will be running a CR Engineering T38 on my escort cos, looking for anything around 420BHP, but I was hoping for a nice fat midrange but I am a bit worried now . Engine will be 7.4:1 (cc'd) , with a std exhaust cam and a BD14 inlet, with mild headwork, having spoke to my tuner I have every confidence his prediction of not a lot more lag than a .48 T34 will be true, as the engine has been specced with this turbo in mind. If I don't like it I might be forced to try a GT30
I also have a GT35 sat under my bench, now a few people have swapped back to the GT30 from this, is the general opinion that a GT35 is a bit too big for a 2.0 YB to be nice to drive on the road?
Talk about secret squirrel
On a different tack, I will be running a CR Engineering T38 on my escort cos, looking for anything around 420BHP, but I was hoping for a nice fat midrange but I am a bit worried now . Engine will be 7.4:1 (cc'd) , with a std exhaust cam and a BD14 inlet, with mild headwork, having spoke to my tuner I have every confidence his prediction of not a lot more lag than a .48 T34 will be true, as the engine has been specced with this turbo in mind. If I don't like it I might be forced to try a GT30
I also have a GT35 sat under my bench, now a few people have swapped back to the GT30 from this, is the general opinion that a GT35 is a bit too big for a 2.0 YB to be nice to drive on the road?
#64
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Originally Posted by Yeti Racing
Originally Posted by marco polo
Franco
you having internal or external
you having internal or external
Going external route now Marco, as thats what Martin has said will suit the build
Cant bloody wait!
#65
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Originally Posted by RWD_cossie_wil
We do this topic every 6 months, all we ever get is Sheady going 8.1-15.1 , Rainbum going anything over 8.1 is a timebomb , and lots of from people, why even bother replying if you are not going to tell us what you are running?
Talk about secret squirrel
On a different tack, I will be running a CR Engineering T38 on my escort cos, looking for anything around 420BHP, but I was hoping for a nice fat midrange but I am a bit worried now . Engine will be 7.4:1 (cc'd) , with a std exhaust cam and a BD14 inlet, with mild headwork, having spoke to my tuner I have every confidence his prediction of not a lot more lag than a .48 T34 will be true, as the engine has been specced with this turbo in mind. If I don't like it I might be forced to try a GT30
I also have a GT35 sat under my bench, now a few people have swapped back to the GT30 from this, is the general opinion that a GT35 is a bit too big for a 2.0 YB to be nice to drive on the road?
Talk about secret squirrel
On a different tack, I will be running a CR Engineering T38 on my escort cos, looking for anything around 420BHP, but I was hoping for a nice fat midrange but I am a bit worried now . Engine will be 7.4:1 (cc'd) , with a std exhaust cam and a BD14 inlet, with mild headwork, having spoke to my tuner I have every confidence his prediction of not a lot more lag than a .48 T34 will be true, as the engine has been specced with this turbo in mind. If I don't like it I might be forced to try a GT30
I also have a GT35 sat under my bench, now a few people have swapped back to the GT30 from this, is the general opinion that a GT35 is a bit too big for a 2.0 YB to be nice to drive on the road?
Mark
#67
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Porkie
YOU READ MY MIND! Oh well that'll cheer Martin up no doubt!
marco polo
All this fucking around trying to decide on what turbo to run Marco, just seemed easier to fork out a little bit more and go external!
YOU READ MY MIND! Oh well that'll cheer Martin up no doubt!
marco polo
All this fucking around trying to decide on what turbo to run Marco, just seemed easier to fork out a little bit more and go external!
#68
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Originally Posted by Mark Shead
Originally Posted by RWD_cossie_wil
We do this topic every 6 months, all we ever get is Sheady going 8.1-15.1 , Rainbum going anything over 8.1 is a timebomb , and lots of from people, why even bother replying if you are not going to tell us what you are running?
Talk about secret squirrel
On a different tack, I will be running a CR Engineering T38 on my escort cos, looking for anything around 420BHP, but I was hoping for a nice fat midrange but I am a bit worried now . Engine will be 7.4:1 (cc'd) , with a std exhaust cam and a BD14 inlet, with mild headwork, having spoke to my tuner I have every confidence his prediction of not a lot more lag than a .48 T34 will be true, as the engine has been specced with this turbo in mind. If I don't like it I might be forced to try a GT30
I also have a GT35 sat under my bench, now a few people have swapped back to the GT30 from this, is the general opinion that a GT35 is a bit too big for a 2.0 YB to be nice to drive on the road?
Talk about secret squirrel
On a different tack, I will be running a CR Engineering T38 on my escort cos, looking for anything around 420BHP, but I was hoping for a nice fat midrange but I am a bit worried now . Engine will be 7.4:1 (cc'd) , with a std exhaust cam and a BD14 inlet, with mild headwork, having spoke to my tuner I have every confidence his prediction of not a lot more lag than a .48 T34 will be true, as the engine has been specced with this turbo in mind. If I don't like it I might be forced to try a GT30
I also have a GT35 sat under my bench, now a few people have swapped back to the GT30 from this, is the general opinion that a GT35 is a bit too big for a 2.0 YB to be nice to drive on the road?
Mark
What sort of ignition values does the Autronic allow you to run at that kind of compression? The only reason I don't (and AVA) like high compression, is the reduction in ignition you have to run to compensate for the high compression. On a heavily used track car, the heat this puts into the engine is immense, so the benefits of high compression are negated by the resultant down-side of the ignition being retarded compared to where it could be with a lower compression. Personally, I would rather run the engine cooler with us much ignition advance as I could have and loads of boost, rather than loads of boost and lots of retard (by comparison) to compensate.
Low compression allows you to run 16-20 degrees on the top line, where if the compression is too high, this can be reduced to single figures....
#69
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Thanks for the replies, quite a lot to digest.........................
Loving Doug's post that Porkie quoted, that's pretty much the stomping ground I was after with the build. Although on more of a tighter budget I'd guess
RE the solid lifters, is it worth fitting these in a relatively standard build? I am guessing this will allow for higher RPM but what else would you require for this?
Franco what is the rest of your spec I would got for an external gate as well while I was at it so yours sounds interesting
Loving Doug's post that Porkie quoted, that's pretty much the stomping ground I was after with the build. Although on more of a tighter budget I'd guess
RE the solid lifters, is it worth fitting these in a relatively standard build? I am guessing this will allow for higher RPM but what else would you require for this?
Franco what is the rest of your spec I would got for an external gate as well while I was at it so yours sounds interesting
#72
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Originally Posted by Chip-3Door
Solid lifters really arent that needed, you can see 8Krpm on the hydraulics.
For a budget build I wouldnt bother as its money that could be spent elsewhere.
For a budget build I wouldnt bother as its money that could be spent elsewhere.
#73
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Originally Posted by Yeti Racing
Originally Posted by Chip-3Door
Solid lifters really arent that needed, you can see 8Krpm on the hydraulics.
For a budget build I wouldnt bother as its money that could be spent elsewhere.
For a budget build I wouldnt bother as its money that could be spent elsewhere.
Revving too 9000 instead would have me wanting to change the conrods as well personally, so I disagree with the figures you are mentioning when applied to a nearly standard engine like the one this thread is about.
#74
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Originally Posted by Chip-3Door
Solid lifters really arent that needed, you can see 8Krpm on the hydraulics.
For a budget build I wouldnt bother as its money that could be spent elsewhere.
For a budget build I wouldnt bother as its money that could be spent elsewhere.
Like you said if it's budget build then maybe not worth it but it is worth doing at the time of engine build rather than thinking about carrying out the conversion at a later date. So what I'm saying Mr Franco is if we are doing it let's do it NOW not after it's fitted into the car.
#75
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Mark is making mine higher compression after the development work on the Dyno. mine was 7.4:1. Im not technical but im sure Mark will say what was going on.
It runs unristricted boost 2.5bar all the way .
Was on Hydraulic lifters @ was rev'ed to 8.3k regularily including pulling 8.3k in 5th (210.2mph). Its now on solid lifters just in case we have the Power to pull past 8.3 in 5th which is 218mph on my present gearing.
It runs unristricted boost 2.5bar all the way .
Was on Hydraulic lifters @ was rev'ed to 8.3k regularily including pulling 8.3k in 5th (210.2mph). Its now on solid lifters just in case we have the Power to pull past 8.3 in 5th which is 218mph on my present gearing.
#76
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Martin, on hydraulics you of course run the risk of losing valve lift at the most important time, high RPM, so I totally agree with you that they are worth doing in a big spec build, was only for this application (cheapy cheapy) that I was saying the limited budget available would be better spent elsewhere (like a decent rear diff for example)
#77
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Originally Posted by MadRod
Mark is making mine higher compression after the development work on the Dyno. mine was 7.4:1. Im not technical but im sure Mark will say what was going on.
It runs unristricted boost 2.5bar all the way .
Was on Hydraulic lifters @ was rev'ed to 8.3k regularily including pulling 8.3k in 5th (210.2mph). Its now on solid lifters just in case we have the Power to pull past 8.3 in 5th which is 218mph on my present gearing.
It runs unristricted boost 2.5bar all the way .
Was on Hydraulic lifters @ was rev'ed to 8.3k regularily including pulling 8.3k in 5th (210.2mph). Its now on solid lifters just in case we have the Power to pull past 8.3 in 5th which is 218mph on my present gearing.
At 8.3K I suspect you were losing power due to the hydraulics, as I reckon the valves were no longer following the desired profile.