GT500R-SP or GT3574R?

[speedjunkie]

I posted this on evil forum a few hours ago, but no one is chiming in. I forgot, most of the knowledgeable people are over here already haha, leaving mostly noobs over there.


I was looking into the GT500R from A-Spec, and when I talked to Sean and told him what I wanted it for he suggested going with a GT3574R customized for my application.

I will mostly be using it for road course and possibly autocross (I know Rich, I know ), but I want to get decent top end from it too. This will most likely never see a drag strip, and only possibly see a few highway runs (I like going from a roll, that's why). I'm more into spirited backroad drives on curvy roads.

This is what the site says for the GT500R...
These setups are capable of 500whp@20psi with the right combination of build and a proper tune. We have seen 503whp@20psi on a large street ported motor. Most customers will see around 430-440whp in the 15-16psi range. With that 15psi being achieved around 3800rpm leaving you plenty of RPM to have a nice power band.

Sean said the GT3574R would be able to reach 14psi around 3400 and still be able to get up to around 450-500whp but it wouldn't be as efficient as the GT500R. He didn't say that verbatim, but that's what I gathered from information he gave me. Obviously this turbo would be ball bearing, and as I said, he said it would be customized for my application.

Being that the GT500R has great response for a good size turbo, it's really hard to turn your back on this one. However, the GT3574R has even better response and can still get pretty high into HP, just not as efficiently. I'm also getting the screamer pipe rerouted back into the DP, and getting everything ceramicoated. For the GT500R kit, with a military discount would be $3919. The customized GT3574R would be about $100 less.

FYI, I have an agressive streetport, RE monster VMIC, wide open exhaust with only a resonator to quiet it a bit (with GReddy Ti exhaust), 1000cc pri and 1600cc sec, HKS twin power, and more but I'm not sure what all matters for your advice.

So guys and gals, what do you think? Which one? Also, people that have either of these (although the customized one will be hard for someone to have haha), please chime in.

[Brent]

My vote is for the GT500 SP. I don't think the GT3574R will give you enough on the top with a large road course. You could prob. reach your horsepower goals with more boost but that will create ALOT more heat which can kill a track car or Auto X car quickly! I run around 12-14psi on my T78 and it stays nice and cool. Most of the other guys that track their FD's, as I'm sure you are aware, run around the same boost level. If I'm not mistaken, Fritz's 95 SSM R2 that is currently for sale had the GT3574R kit on it. He can prob. tell you about it

[speedjunkie]

^You are talking about Fritz Flynn right? Cool, I'll ask him, thanks a million man!

[Brent]

Yep, Fritz Flynn.

[Dr-Rotor]

IS the GT500R turbo similar to a Garret GT3582R AKA 35/40 ?

[speedjunkie]

^I'm not sure to be honest with you. You'll have to ask Sean. Sorry.

[Dr-Rotor]

Also what do you guys mean by road corse? Is that like gymkana or something with the cones? Or race track?

If the GT500R turbo is the same as a GT35R I dont see why you cant use it, People seem to forget when you race that the RPM is up above 3k most of the time. I use a GT35R and boy its insane through 1st and 2nd, spool time is bugger all.

[SPICcnmFD]

Originally Posted by Dr-Rotor

Also what do you guys mean by road corse? Is that like gymkana or something with the cones? Or race track?

If the GT500R turbo is the same as a GT35R I dont see why you cant use it, People seem to forget when you race that the RPM is up above 3k most of the time. I use a GT35R and boy its insane through 1st and 2nd, spool time is bugger all.

Road Course is Race track, like silverstone, le mans, etc. AutoX is cones.

[Brent]

Originally Posted by Dr-Rotor

Also what do you guys mean by road corse? Is that like gymkana or something with the cones? Or race track?

If the GT500R turbo is the same as a GT35R I dont see why you cant use it, People seem to forget when you race that the RPM is up above 3k most of the time. I use a GT35R and boy its insane through 1st and 2nd, spool time is bugger all.

The GT500r is not really that similar to a 35/40. A GT500r spools pretty much just as fast as a GT35r, but has much more top end, comparable to one of the larger turbo's. It suppose to be the best of both worlds. The GT35r that is in question here, is the smaller trim which spools a little faster, but does not have anywhere close to the top end the 500r does.

[speedjunkie]

Road course is like what's in your avatar Dr-Rotor, haha.

[Dr-Rotor]

Haa well then, if your on a proper race track like I do use the 500R or a GT3582R like I have. We seem to have crazy hp numbers down here for some reason but my car is pulling 600nm and 588rwhp on 20psi with a GT3582R. All custom fabricated bits and bobs.

We use a 130 ramp rate on a dyno dynamics if its any consolation to anyone.
The pic in my avatar is me during a superlap event.

[David Jerome]

500R is a 67mm turbo with some customization from A-spec. The site claims 3800rpm spool up but the lowest I have seen(I have seen about 5-6 dyno sheets) was around 41-4200rpm for 15lbs. Still a great setup but I think you would be better off($) piecing together your own kit.

[speedjunkie]

Originally Posted by Dr-Rotor

Haa well then, if your on a proper race track like I do use the 500R or a GT3582R like I have. We seem to have crazy hp numbers down here for some reason but my car is pulling 600nm and 588rwhp on 20psi with a GT3582R. All custom fabricated bits and bobs.

We use a 130 ramp rate on a dyno dynamics if its any consolation to anyone.
The pic in my avatar is me during a superlap event.

Damn that's a nice pic! Nice car too of course.

Part of it might have to do with your altitude, or lack thereof haha. I live above 6000 feet, so our HP numbers are considerably lower. I dyno'd mine at 318 at altitude, but corrected (supposedly at sea level) was 403, at 6700RPMs at15psi in 3rd gear. That was on a Mustang Dyno too, and they're known for having lower numbers.

Originally Posted by David Jerome

500R is a 67mm turbo with some customization from A-spec. The site claims 3800rpm spool up but the lowest I have seen(I have seen about 5-6 dyno sheets) was around 41-4200rpm for 15lbs. Still a great setup but I think you would be better off($) piecing together your own kit.

I'm also getting the manifold and DP, both with a lifetime warranty, a Tial 50mm WG, and I'm paying extra for the WG rerouting to DP and ceramicoating everything. So I think it's well worth it.

Where those ones you've seen the HP model or SP model?

I've pretty much decided to go with the GT500R-SP.

[Dr-Rotor]

Damn that's a nice pic! Nice car too of course.

Part of it might have to do with your altitude, or lack thereof haha. I live above 6000 feet, so our HP numbers are considerably lower. I dyno'd mine at 318 at altitude, but corrected (supposedly at sea level) was 403, at 6700RPMs at15psi in 3rd gear. That was on a Mustang Dyno too, and they're known for having lower numbers.

Thank you.

I never thought of the altitude. I thought the UK was at sea level.
New Zealand is pretty much all at sea level around Auckland, exept if you head out into the mountains. Many GT3582R RX7's over here put out between 400 - 550 whp and many on hub dynos too, depending on other mods too. Not many FDs here use the same fuel as I do or run WI.

My car will be on the dyno again in the near future as the engine builder wants to see how far it goes before it stops making power. I will get a copy of the graph and record the run so you can watch it.

[Dr-Rotor]

Forgot to ask whats the conversion you use to change the power figure depending on altitude?