Let's talk road race engine builds

[gsxitement]

So, As I've been progressing in the road race/time trial world, the desire to build a purpose built, responsive, proper road race engine has grown. The engine in my car now is a built, 9.5:1 2.3 liter, .020 over stroker with +1mm valves HKS cams and a 6076 Garrett. The turbos a bit too big for a responsive road race engine. So, as per rules of the class I want to participate in, I have to run a 2.0 liter, but, the kicker is I'm allowed up to 10.50:1 compression ratio. So that would allow a smaller, more responsive turbo to make a lot of power on lower boost levels. What I want to figure out is all the little areas that can be improved to help the efficiency, durability, longevity and reliability for an engine that's going to be living purely on the road course. Specifically, heat extraction and heat management. I understand the extraction of heat is more a body/chassis situation, but what can be done to keep the heat down, or at least help the engine deal better with heat for prolonged amounts of time. Most of the TT sessions I run are anywhere from 15-30 minutes. So I'd like to figure out the best way to keep lubrication and cooling reliable and consistent. And of course, optimize the gray areas of the rulebook to help performance.

 

[gsxitement]

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[GST with PSI]

What kind of HP range would make you competitive? I know it's more about the delivery, but generally speaking, how much power would you need to be making to be a boss in that class?

 

[gsxitement]

What kind of HP range would make you competitive? I know it's more about the delivery, but generally speaking, how much power would you need to be making to be a boss in that class?

Honestly....not too sure. Nothing like 600hp. But 425-450 with a light car and awd with some killer tires would be tough to beat. If I could get the weight down to really light, you could run even less HP. But if I wanted to keep "stock" turbo, reliably 400-425 would be easily attainable with 10.5:1 compression. I'm at around 465 or so now, and I'm pretty competitive, but the power band is all wrong, especially for the tighter courses. And that's on 15psi. But the power delivery is all wrong. Waiting on the power exiting a corner.

 

[GST with PSI]

OK, cool. What fuel will you race the car on?

 

[gsxitement]

OK, cool. What fuel will you race the car on?

100 octane Sunoco usually. Although the $12.78 a gallon price tag is starting to hurt. That's what I've been putting in the car since I started really dedicating the car to TT stuff. Since I "should" keep a stock displacement engine, a 2.0 long rod is very enticing. A 2.0 long rod with 10.5:1 compression with a matching turbo would be a killer setup I think. That's recommendations from Bobby Gould. And I like that idea a lot.

 

[GST with PSI]

What about E85?

I'm no road racing expert, but I've never been a fan of the high compression builds. A 10.5:1 motor is going to be a lot more picky about what fuel you give it, and what turbo it's paired with. That's especially true for a road race car, which is going to make gobs of heat for a sustained period of time. @Kapok6 I know can speak to this pretty fluently.

If it were me, I'd stick with lower compression pistons (anywhere between the standard 7.8:1-8.5:1) and pair the motor up with a legit set of cams and turbo to match. At the power levels you're looking at, you could run a FP3052 with mods to optimize the setup and never feel a bit of lag. The insta-spool will more than make up for any low end you'd gain with a high compression motor, IMO. Hell, my 3052 spools up so quick that it's constantly surging at anything under 85% throttle. It's unbelievable how quick it spools up: http://www.dsmtuners.com/threads/gstwithpsis-galant-vr4-1837-2000.482807/page-13#post-153652446

The limiting factor here is fuel. If you can get E85, I'd say that's absolutely the way to go. You'll reap the performance benefits, and the cost benefits, especially if you can get it at the pump. You'll need to invest in a fuel system to support, but that's certainly cheaper than a short block build.

Your rule book is gray where it mentions the use of an "aftermarket header". Not sure if this means you're limited to a stock manifold. If so, the FP3052 is a good option. If not, I'd say you'd probably be doing a bit better if you could find a T3 flanged GT30 setup.

Bottom line, I think you'd be hard pressed to find a harder hitting 450whp setup than a BB GT30 set up to the tits. If you really matched and properly paired each part to suit your road racing goals, I think you'd be a force to be reckoned with. Then again, I'm just some guy who builds shitbox Galant street cars. Admittedly, I have zero experience road racing on a real track.

@TSiAWD666 @talon77 @Black95TSIawd @ileagleracing

 

[gsxitement]

What about E85?

I'm no road racing expert, but I've never been a fan of the high compression builds. A 10.5:1 motor is going to be a lot more picky about what fuel you give it, and what turbo it's paired with. That's especially true for a road race car, which is going to make gobs of heat for a sustained period of time. @Kapok6 I know can speak to this pretty fluently.

If it were me, I'd stick with lower compression pistons (anywhere between the standard 7.8:1-8.5:1) and pair the motor up with a legit set of cams and turbo to match. At the power levels you're looking at, you could run a FP3052 with mods to optimize the setup and never feel a bit of lag. The insta-spool will more than make up for any low end you'd gain with a high compression motor, IMO. Hell, my 3052 spools up so quick that it's constantly surging at anything under 85% throttle. It's unbelievable how quick it spools up: http://www.dsmtuners.com/threads/gstwithpsis-galant-vr4-1837-2000.482807/page-13#post-153652446

The limiting factor here is fuel. If you can get E85, I'd say that's absolutely the way to go. You'll reap the performance benefits, and the cost benefits, especially if you can get it at the pump. You'll need to invest in a fuel system to support, but that's certainly cheaper than a short block build.

Your rule book is gray where it mentions the use of an "aftermarket header". Not sure if this means you're limited to a stock manifold. If so, the FP3052 is a good option. If not, I'd say you'd probably be doing a bit better if you could find a T3 flanged GT30 setup.

Bottom line, I think you'd be hard pressed to find a harder hitting 450whp setup than a BB GT30 set up to the tits. If you really matched and properly paired each part to suit your road racing goals, I think you'd be a force to be reckoned with. Then again, I'm just some guy who builds sh**box Galant street cars. Admittedly, I have zero experience road racing on a real track.

@TSiAWD666 @talon77 @Black95TSIawd @ileagleracing

You absolutely bring up a very valid point about the compression ratio. The car right now is on 9.5:1 Mahle pistons that are absolutely fantastic and I love them greatly. The thing I was thinking about as far as that is it to keep it on a "stock" turbo just to try and keep costs down. Lol. I know E85 is the hot shit, but I'm still a big gasoline fan. My next race is in October at Lime Rock, so I'll check the pumps to see if they even offer it there. I know some tracks offer E90 but I haven't been to any that have it available. Definitely want to go back to a BB turbo. You can check my build thread about the fiasco I just had with my turbo in April. Long story short, it WAS BB, but now is a JB, and, as much as they said "minimal difference in lag", I definitely experience a much longer wait time for boost coming off the corner than I had previously.

 

[gsxitement]

Another factor about the heat is why I'd like to run less boost. I know it's all relative since if I run more boost on lower compression, or less boost on higher compression, it's all going to come out in The wash as far as heat generation. It's just which direction do I want to go in. Me personally, I'd like higher compression on less boost, just for the response aspect. But like you said, a properly sized engine will be very responsive and make great, reliable power. I must've spent 3 months sizing everything out for the motor that's in the car now. Granted, when I did the sizing and purchase of the parts, the car was more geared towards a street machine, but the package works as intended. Responsive off boost and a shitload of power on 15 psi.

 

[GST with PSI]

As I'm sure you know, it's going to be a trade off. Bigger turbo means more power on less boost, but more lag. Smaller turbo means higher boost for more power, which brings the heat. I'm running around 30psi, but I think you could probably get away with far less boost on the same GT30 setup tailored to make power where you need it. Again, I'm very confident this can be done on a lower compression setup with the right turbo. Pair good cams, and intake manifold and proper tune with that turbo, and I think you'd be set. I'm not sure what rev range you're seeing on the low end during your track outings, but on my car anything over 3.5k RPM and I get damn near instant boost. I can't imagine you'd ever be far below that in a given gear on the track.

If you're looking for response optimization, a BB turbo is a must for road racing. The transient boost response will make a big difference.

Lastly, stop being a gasoline fan. Get off the gasoline train, because @ 12.78 for 1 gallon of 100 octane, you're doing it wrong

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[gsxitement]

As I'm sure you know, it's going to be a trade off. Bigger turbo means more power on less boost, but more lag. Smaller turbo means higher boost for more power, which brings the heat. I'm running around 30psi, but I think you could probably get away with far less boost on the same GT30 setup tailored to make power where you need it. Again, I'm very confident this can be done on a lower compression setup with the right turbo. Pair good cams, and intake manifold and proper tune with that turbo, and I think you'd be set. I'm not sure what rev range you're seeing on the low end during your track outings, but on my car anything over 3.5k RPM and I get damn near instant boost. I can't imagine you'd ever be far below that in a given gear on the track.

If you're looking for response optimization, a BB turbo is a must for road racing. The transient boost response will make a big difference.

Lastly, stop being a gasoline fan. Get off the gasoline train, because @ 12.78 for 1 gallon of 100 octane, you're doing it wrong

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!!! Well, to be fair, that's the price for 100 octane at the track. Obviously gonna be way more expensive there than outside since it's your only option. And believe me, I'm onboard with the BB turbo, but I had no other option at the time but to convert mine to JB, which I was very unhappy about. And I was hesitant to go E85 when it was a street car cause here in NYC, it's very difficult to find without crossing Bridges and paying tolls. But let's talk about the motor itself. Long rod 2.0? Keep it 2.3 ( which someone could protest if they felt like I was cheating and they'd win)

 

[GST with PSI]

Keep it 2.3L would have been my first suggestion, but I didn't think that was an option.

 

[gsxitement]

Keep it 2.3L would have been my first suggestion, but I didn't think that was an option.

Too be honest, it's a regional series, so the likelihood of someone protesting is very slim. I mean, the tech guy looks at my car and kinda just makes sure the safety is good. But it's fairly obvious it's outside the realm of "legal"

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[GST with PSI]

Well, hopefully they don't dig up this thread

Hell, you've already got a sweet Archer T3 mani. I'd say source a GT30 cartridge of your choosing and see what that does.

What's our O2 setup like?

 

[gsxitement]

Well, hopefully they don't dig up this thread

Hell, you've already got a sweet Archer T3 mani. I'd say source a GT30 cartridge of your choosing and see what that does.

What's our O2 setup like?

It's a T4. That's what sucks is I'm stuck with a T4 frame turbo until I can get a new manifold, which I don't want cause I love this one. O2 situation is the factory O2 sensor in the downpipe and a wideband further downstream from that. And with the T4 frame, I think the smallest I can go is a 35.

 

[Kapok6]

What about E85?

I'm no road racing expert, but I've never been a fan of the high compression builds. A 10.5:1 motor is going to be a lot more picky about what fuel you give it, and what turbo it's paired with. That's especially true for a road race car, which is going to make gobs of heat for a sustained period of time. @Kapok6 I know can speak to this pretty fluently.

To touch on this, i'd say for me (a non-professional builder/tuner), I don't care for high comp 4g63s. Quicker throttle response and a little bit faster spool up just aren't worth the even narrower tuning window for me. Keep in mind that every engine is different, and I am only going off my personal experience. 10.5:1, GSC S2 cams, 1550cc injectors, DSM 76 HTA turbo, e85 30-37psi depending how froggy I was feeling that day). The car needed 9.2-9.5:1 afr on a gas scale at peak torque at anything over mid 20's for boost to keep knock away and not pull timing. Ramping up to low to mid 10's in the upper rpms. Timing was around 5deg in peak torque ramping up to around 13. The car seemed VERY picky about the AFR's and timing, and if you were off buy just a little, it made a big difference.

If you have a reputable builder/tuner that's going to be doing everything with the car, by all means, have fun with high comp. For most of us bozos who have budgets, do our own work, etc, i'd advise against it.

I mean, Curt Brown, (who built my motor), put down 600awhp with GT35R based turbo on an 11:1 motor with 93oct pump gas. But none of us are Curt, and few of us are similar, so i'd just say to leave yourself some wiggle room in regards to things that may go wrong. High comp can be unforgiving imo.

 

[gsxitement]

To touch on this, i'd say for me (a non-professional builder/tuner), I don't care for high comp 4g63s. Quicker throttle response and a little bit faster spool up just aren't worth the even narrower tuning window for me. Keep in mind that every engine is different, and I am only going off my personal experience. 10.5:1, GSC S2 cams, 1550cc injectors, DSM 76 HTA turbo, e85 30-37psi depending how froggy I was feeling that day). The car needed 9.2-9.5:1 afr on a gas scale at peak torque at anything over mid 20's for boost to keep knock away and not pull timing. Ramping up to low to mid 10's in the upper rpms. Timing was around 5deg in peak torque ramping up to around 13. The car seemed VERY picky about the AFR's and timing, and if you were off buy just a little, it made a big difference.

If you have a reputable builder/tuner that's going to be doing everything with the car, by all means, have fun with high comp. For most of us bozos who have budgets, do our own work, etc, i'd advise against it.

I mean, Curt Brown, (who built my motor), put down 600awhp with GT35R based turbo on an 11:1 motor with 93oct pump gas. But none of us are Curt, and few of us are similar, so i'd just say to leave yourself some wiggle room in regards to things that may go wrong. High comp can be unforgiving imo.

Oh, I'm one of those bozos . I appreciate all the insight. Definitely putting me in a direction for the build I'll do next winter. Hopefully we'll be in a house by then so I can have a nice garage to do my work. Commuting an hour to work on my car is annoying .

 

[GST with PSI]

Jesus. That's a T4 mani? No wonder it's so laggy.

By O2 setup, I mean what housing/downpipe/etc? Custom?

Since everyone DSM likes to drag race, that setup shouldn't be terribly hard to sell. There's definitely room for improvement there.

Maybe Kyle has an exchange program

@Archer Fabrications

 

[gsxitement]

Jesus. That's a T4 mani? No wonder it's so laggy.

By O2 setup, I mean what housing/downpipe/etc? Custom?

Since everyone DSM likes to drag race, that setup shouldn't be terribly hard to sell. There's definitely room for improvement there.

Maybe Kyle has an exchange program

@Archer Fabrications

Yeah it's all my own stuff that I made. I'm gonna have to run this for a while since I just don't have the cash at the moment for a new turbo. The manifold size is deceiving since the wall thickness is schedule 40. I'd love to go GT30 or whatever the new flavor is...GTW or whatever. Just can't afford to change the setup. Gotta love going road racing with a drag race setup . We'll see what I can do over the winter engine wise. Probably just a refresh to keep the costs down. It'll be a season or two before I can buckle down to make a full on road race setup. Need a shell to really make into a full on racecar.

 

[Black95TSIawd]

Gearing... its all in the gearing!

Are you limited on what you can do with the gearing? This is my future setup:

Destroked 2.2L with 8.5 to 9k rev limit. Evo 4.3 final drive. The extra displacement will give me some help with spool, but most importantly, the higher final drive will keep the RPM up and help the motor accelerate faster. This will help any turbo spool. The higher rev limit will still give me MPH at redline. (I need all the RPM I can get to keep 2nd gear around 70mph for autocross)

Substitute a 2.0 motor instead for you and it could be a promising setup.


Not sure if you've ever driven a 4g with higher compression. Off boost is noticeable, but spool and torque feel the same. Throttle might be a little crisper, but that's it. As mentioned above, the tuning is pretty tough. Not sure if I would want to worry about that for more than a quarter mile at a time.

 

[gsxitement]

Gearing... its all in the gearing!

Are you limited on what you can do with the gearing? This is my future setup:

Destroked 2.2L with 8.5 to 9k rev limit. Evo 4.3 final drive. The extra displacement will give me some help with spool, but most importantly, the higher final drive will keep the RPM up and help the motor accelerate faster. This will help any turbo spool. The higher rev limit will still give me MPH at redline. (I need all the RPM I can get to keep 2nd gear around 70mph for autocross)

Substitute a 2.0 motor instead for you and it could be a promising setup.


Not sure if you've ever driven a 4g with higher compression. Off boost is noticeable, but spool and torque feel the same. Throttle might be a little crisper, but that's it. As mentioned above, the tuning is pretty tough. Not sure if I would want to worry about that for more than a quarter mile at a time.

My car is a 2.3 with 9.5:1 pistons. And yeah, off boost it's still very drivable. But since it's gonna be more dedicated to track sessions, I can focus more on mid range and top end operation. Where can I find info on the gearing changes?

 

[Black95TSIawd]

My car is a 2.3 with 9.5:1 pistons. And yeah, off boost it's still very drivable. But since it's gonna be more dedicated to track sessions, I can focus more on mid range and top end operation. Where can I find info on the gearing changes?

Hm.. though your OP said you're going back to 2.0. I wouldn't do the gearing with the 2.3. It just doesn't rev high enough to take advantage.

There is very little information available about the higher final drive. PM @twicks69 as he might even be able to get you everything you would need.

 

[Archer Fabrications]

It's a T4. That's what sucks is I'm stuck with a T4 frame turbo until I can get a new manifold, which I don't want cause I love this one. O2 situation is the factory O2 sensor in the downpipe and a wideband further downstream from that. And with the T4 frame, I think the smallest I can go is a 35.

We can make you a T3 if you want

 

[gsxitement]

Hm.. though your OP said you're going back to 2.0. I wouldn't do the gearing with the 2.3. It just doesn't rev high enough to take advantage.

There is very little information available about the higher final drive. PM @twicks69 as he might even be able to get you everything you would need.

Yeah, the idea was to go back 2.0 just in accordance with the rule book. Trying to be legal. So, if I was to go to 2.0 long rod with a GT30 and proper compression ratio, that final drive would be optimal for the revs I'd be turning. Don't ever let anyone say the 4G isn't a versatile platform . We'll see what happens. Doing a build of this magnitude is still a year or two off.

 

[gsxitement]

We can make you a T3 if you want

Maybe over winter when it comes back to you. Just gotta somehow convince the wife that a 1500 turbo is the right move after spending 800 to get the T4 fixed. Why the hells racing gotta be so expensive????