YES! I have already searched and can't really find anything more than people talking about big HP numbers.
I'm going to get an S13 and build it up to be a mean open lapping track machine. I was considering an SR20DET due to more displacement and the fact that it'd be a newer motor and mods are cheaper and easier to come by than an CA18DET.
The only problem is the price...
So, can a CA18DET make ~280-300rwhp and still spool the turbo between 3000-3500RPM while still having excellent transient response? I'd need this turbo to INSTANTLY spool say 4000RPM and above. I understand the terminology of what makes a turbo "tick," but I still don't really see how to size them all that efficiently for spoolup and response.
About the powerband, it'd be REALLY sweet if I could make good power out to 7800-8000RPM. This would allow me to be down a gear in some long sweepers and not worry so much about spoolup time. Although sometimes I will have to be ~3000-4000RPM at the beginning of a corner, and I will need good power to plant the rear end. You can't always keep it "high in the revs" on a road course, just because if you run out of gear in the middle of a corner and tap the rev limiter, you are most likely going into the nearest wall. So you short shift and have to pull around with the higher gear.
Another thing that somewhat concerns me is the lack of mods available for this engine. After CA16DE cams(of which there is a debate as to whether they even improve things!) and the normal exhaust/intake dealies, you seem pretty much stuck besides going with a big honking turbo. Of course that's not really an option due to the spoolup requirements of road racing.
Lastly, does either a CA18DET or an SR20DET enjoy a weight advantage? If it is under 10-20lbs then it is not really enough to worry about and the cheaper engine is smarter, but if it is closer to 40-50lbs then we're talking something significant.
If I got a CA18DET, I'd probably put in new rod bearings while the motor was out just to eliminate that as a possible problem of an old engine and it seems this is a common issue with the motors. Do the cylinder bores tend to hold up in these motors, or does the compression go down with higher miles? I'm going to be pushing this motor hard, really hard - but I'll install things like an oil cooler and beefier radiator and a FMIC to handle the heat side of things. If the internals are up to it, I don't see why this little motor can't be a real winner.
CA18DET: Fast spoolup and sweet powerband?
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r34 gtr
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there is a wealth of parts available for this engine, you just have to know where to look. i dont think there is a big difference in weight, because of the ca's iron block as opposed to the aluminum block of the sr. im sorry, but i cant help you with the turbo issue as i still have my tiny t25, which im guessing i will for a long while.
3500 rpms is a bit rediculous. If you are road racing you shouldn't need a turbo to spool up that quick. Once you get going you'll be fine and if it ever gets that low all you need is a downshift. I could see where you would want a turbo to spool that quickly in autox but other than that i see no need for it.
I don't see a ~3500RPM spool time as that ridiculous... I'm not looking to make 400rwhp here. I think anything more than 300rwhp would start getting a tad crazy in a ~2400-2500lb car. Sure, I'll probably get greedy at some point and want more, but I don't think my goals are unrealistic right now.
You can't always downshift and go into a corner in a lower gear. If there is a really long, sweeping corner, your exit speed at track out can be 20-25mph higher than your entrance speed, and you cannot shift in that whole period. I routinely go into corners at ~40-45mph in 3rd gear with my M3 just because I'd run out of 2nd gear and have a problem. Yet with a peak torque at 3800RPM and a strong pull from 1500RPM it is not so much an issue.
Road racing is a completely different animal than most people realize until they do it. You might not have a 15mph corner, but you still have to use a whole heck of alot of your powerband to get around the course the fastest. If you are not on the brakes, you are on the gas and you can't really shift in a corner or series of corners. So you'll find yourself short shifting a good bit shy of redline alot of places around the track so that you will have a good pull throughout the whole next section. Now does it make sense why I want the broadest powerband possible? I'm not TOO concerned with peak power figures, I'm just throwing those out as a possible amount of "pull" I want around the track to keep up with/embarass faster cars on the straights as well as the corners. I'd much rather take a little more torque and a fat meaty powerband over a peaky curve with good peak numbers.
Ok, so what about spooling fully by 3800RPM with a good transient response? I'd of course try to do everything I could to reduce lag. GReddy O2 extension pipe, good sized downpipe and exhaust with a straight/test pipe instead of a cat. I would also try out a tubular manifold if I could find one reasonably priced like you can for the SR's.
Ok, so let's say it can't spool up at 3500, and it says takes until 4200RPM(which is MORE than reasonable). Can the engine rev to 8000 or beyond reliably with some slightly hotter cams and valve springs? If I can bring it up a hair over 8k then the slow spool time isn't as much of an issue.
This engine seems like it should be able to get the snot rev'd out of it with good valvesprings and enough cam to breathe up that high. How would you handle the software issue of the revlimiter in the stock ECU?
You can't always downshift and go into a corner in a lower gear. If there is a really long, sweeping corner, your exit speed at track out can be 20-25mph higher than your entrance speed, and you cannot shift in that whole period. I routinely go into corners at ~40-45mph in 3rd gear with my M3 just because I'd run out of 2nd gear and have a problem. Yet with a peak torque at 3800RPM and a strong pull from 1500RPM it is not so much an issue.
Road racing is a completely different animal than most people realize until they do it. You might not have a 15mph corner, but you still have to use a whole heck of alot of your powerband to get around the course the fastest. If you are not on the brakes, you are on the gas and you can't really shift in a corner or series of corners. So you'll find yourself short shifting a good bit shy of redline alot of places around the track so that you will have a good pull throughout the whole next section. Now does it make sense why I want the broadest powerband possible? I'm not TOO concerned with peak power figures, I'm just throwing those out as a possible amount of "pull" I want around the track to keep up with/embarass faster cars on the straights as well as the corners. I'd much rather take a little more torque and a fat meaty powerband over a peaky curve with good peak numbers.
Ok, so what about spooling fully by 3800RPM with a good transient response? I'd of course try to do everything I could to reduce lag. GReddy O2 extension pipe, good sized downpipe and exhaust with a straight/test pipe instead of a cat. I would also try out a tubular manifold if I could find one reasonably priced like you can for the SR's.
Ok, so let's say it can't spool up at 3500, and it says takes until 4200RPM(which is MORE than reasonable). Can the engine rev to 8000 or beyond reliably with some slightly hotter cams and valve springs? If I can bring it up a hair over 8k then the slow spool time isn't as much of an issue.
This engine seems like it should be able to get the snot rev'd out of it with good valvesprings and enough cam to breathe up that high. How would you handle the software issue of the revlimiter in the stock ECU?
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undertaker
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a nice ball bearing turbo with a suitable turbine housing A/R (approx .6 for a GT25XX should work) will supply the response and power you need but as it alone will cost a lot you may want to reconsider which motor will suit you best. the ca loves to rev but i suspect you may need to upgrade more than just the valvetrain to keep it reliable here. rev limits are easy to change if you have the mapping software and a lot of people do these days.
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McAdam
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garrett VNT-25 turbo rebuilt with a 360 degree thrust bearing for fun and converted with a big T28 500cfm intake wheel and I think a .42 ratio housing, not sure, will let you know in a few weeks! muahahahhahhaa!
This upgrade is a direct boltin for the T2 equipped 90-91 VNT turbo applications. The turbine section of the VNT turbo is matched to a larger 500cfm T28 compressor wheel and equipped with the 360 degree severe duty thrust bearing system for added durability at high boost pressure. The pictures below show the factory compressor wheel dwarfed in the modified compressor housing and also the complete Super 60 T2 VNT unit.
from a website that will make me one with my good core for $695.
McAdam
This upgrade is a direct boltin for the T2 equipped 90-91 VNT turbo applications. The turbine section of the VNT turbo is matched to a larger 500cfm T28 compressor wheel and equipped with the 360 degree severe duty thrust bearing system for added durability at high boost pressure. The pictures below show the factory compressor wheel dwarfed in the modified compressor housing and also the complete Super 60 T2 VNT unit.
from a website that will make me one with my good core for $695.
McAdam