Which turbo to use..

Turbo and Supercharger discussion
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Which turbo to use..

By Treezy
- Wed Oct 21, 2009 2:20 am #151978 I'm building an ITR motor when I get back from Iraq and I'm trying to decide which turbo to use. I've found a lot of info and even videos on similar setups, so I'm kind of in the range of a GT35R. I've driven a coupe, fully built B16 with virtually the same exact setup as I'll have running a GT30R and it was extremely potent, but I don't have the numbers it put down. I've also watched a video of a hatch with an ITR, pistons, rods, and cams pushing both a 30, then a 35. Their 1/4 mile was about a full second difference. Any opinions?
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By That One Dude
- Wed Oct 21, 2009 2:43 am #151986 What are the specs of the B18C5 you will be building? Are you planning on 81x89? 84x89? Somewhere in between? What pistons? What crank? What rods? What cams? What intake manifold? What turbo manifold?

If you're looking to turbo the stock B18C5, think again. IMO, the CR is too high for more than about 5psi on 93 minimum octane. IIRC, the CR of the B18C5 is around 11.6:1. I know a guy who ran an 11:1 built LS on 15psi, but he was running nothing shy of 116 octane fuel and ridiculous timing with a sleeved block at 84x89. THAT was a fast as shit EG hatch... BUT, I would never recommend anyone run more than 10:1 on boost unless you plan on rebuilding your engine after every drag season, and possibly every once in a while during the season.
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By Treezy
- Wed Oct 21, 2009 10:04 pm #152152 I've been going over a few different ideas as to which and what I'll be using. Since I'll be gone for a long time, and then not have but a short time between getting back and moving overseas.. I've decided not to build it myself so I don't run into "as many" snags as I might. I've spoken to a race company and asked them to build it for me, with the knowledge that it will be for boost. The plan is currently to bore to 84 and sleeve it, all forged internals, and still deciding on the head work. They make their own performance parts so it's an option as well. It'll be fully built and by an actual race company and ready to install when I get back. I was looking to put down some serious numbers, but now that I'm off that kick I'm seriously looking to be in the area of 501-550 on a dyno, but drop to about 15-17psi for the street. The car is being built for show, but I love having the power behind it for when I actually do drive it to a show or event.

Sorry, stock crank micropolished, CP pistons, rods I'm deciding on, actually found a 72mm TB, and looking at manifolds.. I still have several months to get my parts list finalized..
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By That One Dude
- Thu Oct 22, 2009 3:34 am #152205
Treezy wrote:I've been going over a few different ideas as to which and what I'll be using. Since I'll be gone for a long time, and then not have but a short time between getting back and moving overseas.. I've decided not to build it myself so I don't run into "as many" snags as I might. I've spoken to a race company and asked them to build it for me, with the knowledge that it will be for boost. The plan is currently to bore to 84 and sleeve it, all forged internals, and still deciding on the head work. They make their own performance parts so it's an option as well. It'll be fully built and by an actual race company and ready to install when I get back. I was looking to put down some serious numbers, but now that I'm off that kick I'm seriously looking to be in the area of 501-550 on a dyno, but drop to about 15-17psi for the street. The car is being built for show, but I love having the power behind it for when I actually do drive it to a show or event.

Sorry, stock crank micropolished, CP pistons, rods I'm deciding on, actually found a 72mm TB, and looking at manifolds.. I still have several months to get my parts list finalized..


Try a ramhorn bottom mount manifold. Less tubing to worry about on the charge side of things. And I think it looks cleaner...

Check out Carrillo rods. ALL of my Supra friends run them because they are good for upwards of 1500rwph on the Supras. I would imagine they would be more than ample for a 500fwhp Honda engine.

What company are you using?

72mm is awfully big. A full centimeter bigger than the stock ITR TB. For IM, check out the Edlebrock VictorX. Bad ass for turbo applications.

Any chance you would use an LS crank? Longer stroke for better torque. Although in a turbo application, you probably won't be too worried about scavenging more torque. However, if you choose to go with an LS crank, let me know, I have one laying around that I could sell to you.

Not to mention, balance everything. That should be a given.

At 84x87.2, shooting for 500whp, Perhaps a GT30 would be enough.

I'm not too familiar with the different turbos and such, but I do know and understand the parts and concepts behind turbocharging. Mainly from an aircraft stand point, but it's essentially the same as automotive turbocharging.
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By Treezy
- Thu Oct 22, 2009 11:19 pm #152390 Thanks, I'll def look into the ramhorn and carillo to see how they'll fit my app. I'm going through Laskey Racing, great work and the price is pretty reasonable for the product. I was looking for the largest TB I could find.. There's plenty in the 60's, a couple 70mm's, but only OBX-R makes the 72mm.. At least that's the only one I could find after a ton of shopping. I even talked with people who bore out TB's and they said they couldn't do it for me. If it turns out to be a bad choice, there's plenty of 68-70's to choose from. I'm leaning toward the GT35R since I'll have more power to push it, but I'll definitely be doing a lot more research on it over the next few months. And thanks for the offer, but I'm good on the crank.
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By That One Dude
- Fri Oct 23, 2009 3:10 am #152422 Carrillo rods are bad ass. They aren't cheap by any means, but totally worth it if you don't want to blow shit up.

And the ramhorn flows better than just about any other turbo manifold out there giving better spool time and higher efficiency on the exhaust side of things.

I'd stick with the 70mm personally. But that's totally your call.
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