Ls 388hp 301 tq, kinda stock internals,before/after results

sewell94 · Post by **sewell94** » Mon Dec 03, 2007 4:19 am

Kinda cool to do a before and after. But its a B18b, that was built for NA, it has jdm p30 pistons(worked out to 11.5 cr), arp rod bolts, Jg ported LS head, skunk 2 manifold, Crower Stage 3 cams and valvetrain. previously tuned on ectune made 205hp and 140ish tq.

So owner decided to go turbo. It has a drag manifold, .48 ar t3/t4, 38 tial wg, godspeed ic, blitz bov, 750cc inj, and everything engine wise is the same. I tuned it about a week ago and it had alot of boost issues, it wouldn't hold steady, would go to 15lbs then drop to 10-11lbs. I thought maybe the cams are to big for a log style manifold, or*maybe* a boost controller issue. So owner changed the vaccum lines around, so he brought it back for some touch up. Boost holds better but still bounces around quite a bit. Its his daily driver with AC so we stopped at ~15lbs. Made 388Hp 301 tq on pump gas. I kinda wanted to go more but it's his daily driver, with a fairly high cr for boost on 93 and with BC issues, so i seen no reason to push it.

Boosted K20 · Post by **Boosted K20** » Tue Dec 04, 2007 8:46 am

damn! im suprised it made so much power all motor. what dyno are you using?

Civic Tsi · Post by **Civic Tsi** » Tue Dec 04, 2007 11:19 am

I'm not surprised. I was suppose to tune a somewhat similar setup. It made previously 205whp on a mustang dyno. But that day I had 3 cars to dyno tune and he forgot his lock nut so I had to street tune it. He said his car never drove so smoothly and never came back for the dyno tune

Is the boost falling down after 6700rpm ?

sewell94 · Post by **sewell94** » Tue Dec 04, 2007 1:22 pm

My dyno is a land and sea dyno water brake, reads similar to mustang or superflow, i have the correction factor set so that it reads like a dynojet, but still reads lower compared to most DJ's. I get alot of rotary guys that tell me it reads too low, for referance i had an na rotary car that weighed 2250lbs make 370 hp go 10.50, Boost wasn't real steady, i never had any issues with drag manifolds not holding steady untill the last 2 cars i've tuned with them, and they were using electronic bc's, all of the others i've tuned over the years had manual BC's. I think some of the wavyiness is from how he has his dump tube routed, car drives very smooth on the street.

B16CRXT · Post by **B16CRXT** » Wed Dec 05, 2007 7:33 am

Were his cams set at zero? They might be overlapping too much...I have a VERY similar setup with forged internals.

b18b10psi · Post by **b18b10psi** » Tue Feb 05, 2008 3:58 pm

Can you please tell me a little about this car. I am in the middle of a turbo b18b build and i have never seen a b18b turbo build such enormous torch at such low RPM's. Having 200 lb/t at 4000rpm is an incredible setup. I am interested in whether or not this car is holding together because of the strain from the torch number put out. Can you tell me anything about this car that might be helpful. I currently have a b18b transmission JUST rebuilt with a Quaife LSD. I am just starting to get into building the engine and was going to go with stock compression forged pistons but i am know considering higher compression pistons. Do you thing that torch curve is a result of the cams, high compression or both? PS, i also have a .60 a/r airesearch turbo. I noticed your running a .48, did you run a smaller turbo to compensate for the higher compression or what was your reasoning?

B16CRXT · Post by **B16CRXT** » Tue Feb 05, 2008 6:17 pm

if you run the stage 3 cams, you need the higher compression.I have a near identical setup to the N/A setup here except I'm using JE forged pistons at 11.5 82mm, and eagle rods. portwork done to the head and a 70mm tb. I didnt get near at close to 200whp as he did. I'm curious about some other details on his build. what header and exhaust was he running? injector size? throttle body? What sort of timing adjustments did you do to make that much power? Mine peaked at 174whp and 137wtq. Pretty much from the start of the graph it had about 120tq. I've got a 2.5\" tapering to a 2.25\" exhaust with a oe replacement muffler to keep it quiet.

sewell94 · Post by **sewell94** » Tue Feb 05, 2008 9:26 pm

The motor held up great, well its apart currently, but thats because the owner decided to take it through a 3 dollar car wash with underbody sprayers with a cold air style intake, so he bent all of the rods, lol. But a good side to that is, that i got to dissassemble the engine and check everything out, the pistons/rings look a PERFECT. The owner trashed the hell out of this car, so i was very happy to see how it looked internally. We are throwing another set of stock rods with the same pistons back in. I don't remember which header or TB he had on the car, but it had a 3 inch exhaust. It ended up at about 30-32 degrees at 8k at WOT, if i remember correctly. I think the tq is that the combination works well together, the cams are just starting to come on, and the small housing gets the thing spooling very well. To be honest it wasn't planned that way, i had a turbo kit laying around, and we put it on his car. I guess we got lucky

I can say for a fact that the rumor of having too big of an exhaust on an NA car and that a smaller exhaust is better for TQ is complete BS. We did a back to back test of a buddies B20vtec with ITB using the 3 inch thermal (he wanted to get rid of raspy sound) and put a 2 1/4 thermal on, and lost hp and tq across the board but the biggest difference was up top, it was in the neighborhood of a 20hp loss. I'm pretty sure if you had a bigger exhaust and better muffler you'd pick up about the same.