MC-14

Just got my turbo GSR street tuned today with Crome. It's making 240 WHP and 236 FT-LB torque @ 14.5 psi with 550 cc injectors and Greddy Turbo kit w/intercooler. Just wondering how much power you guys are making with this kit. BTW....all internals are stock

Provocateur

The torque is good but the power is really low for that much boost. I made 262/202 on 10 psi with my old Greddy kit setup. It was self-tuned on Crome with 450's, CTR cams, and a 2.5" DP/cat.

Do you have a dyno plot?

MC-14

It kind of ramps down toward the end. The spring on those wastegate is pretty soft, so that can be fixed with a helper spring. That should keep it linear across on the top end. I don't really know why the power aren't higher. I would think it would be much higher at 15 psi. We checked for boost leak before and it checked out good, and the turbo has a fresh rebuild. No damage to turbo components prior to the rebuild. Any clues..................?

Provocateur

Your dyno plot looks...strange. Mine looks identical up until around 4500 and keeps climbing while yours falls flat on its face at 4800. If the motor is healthy and boost is staying consistent, something is very wrong with the tune.

For comparison, here is my dyno plot (we were having issues with the ignition pickup, so that would account for the gap around vtec engagement):

MC-14

I honestly think something is wrong with my turbo. It reaches max boost around 4500, so it's obviously building boost pretty late, which is why it flat lines around 4800. Not quite sure what I want to do yet, but I bet that turbo is no good. I'm thinking maybe to take it out and send it in for a professional rebuild or buy another one. Either way I'm thinking about keeping the 18G turbo, because I don't want to spend anymore money on further modifications for downpipe and manifold. That way I can spend the money on my future build on an EK. What do you think?

Provocateur

Without any changes to the super-restrictive Greddy elbow and 2" downpipe, full boost at 4500 sounds dead on. I could never figure out why such a small turbo lagged like a 57 trim but had absolutely no balls up top but it does. If you are building full boost, I can assure you that nothing is wrong with the turbo, the problem lies in the exhaust setup. If you upgrade to at least a 2.5" downpipe with a 3" exhaust, I guarantee you can be making full boost at 3500-3800 considering at 4500 feet I was fully spooled at 4000.

If you have the Crome tune available, I would love to take a look at it. That way, we can actually determine if it is a shoddy tune or something else.

MC-14

I'm running 2.5" Piping from half of the downpipe to the rear with 2.5" exhaust and high flow cat. Can't really go bigger on the exhaust because of my custom setup. I'm pretty sure the tune is good, because my tuner is really reputable on boosted hondas and Rally cars. I don't have the Crome tune available, but let me see if I can get it from my tuner. Thanks for the help!

MC-14

Provocateur, what do you think I can do to check out the power problem? I've been researching everyones dyno results, and it seems everyone is making more power at 10 psi. My tuner had tuned it 3 times within a month, and it's showing the same result, but only better each time. First tune, it wasn't reaching full boost until 5000 rpm. Changed cat and new custom 2.5" exhaust system for 2nd tune. 2nd tune did much better, but still wasn't building boost until 5000. Finally figured out the problem that the wastegate wasn't completely closed so adjusted the wastegate actuator stem to close it. So 3rd tune is as shown in the dyno chart above. It did much better in the 3rd tune, but power doesn't look too good. I was pushing it pretty hard with the factory Greddy blue box and 310 injector prior to the chipped ecu. Not sure if it messed up anything? Although....I've been losing half a quart of oil every 1-1.5 months. Can there be a potential leaky valve seal? BTW...the motor has 60k miles on it.
Checklist: 1.) Full boost at 4500
2.) Boost Leak Check and passed
3.) 230 psi compression across all cylinders
4.) 2.5" Piping Exhaust and high flow Cat
5.) NGK plugs gapped at .030
6.) New Fidanza Flywheel with clutch.

Not sure if I've missed any other test.

Spec R

dyno dynamics dyno's read WAY different than the more common Dynojet.

so that 240whp on that DD is more like 280-290 whp on a Dynojet.

As far as what you're boosting, in my LS, my 18G would hit 8 psi by 3400rpm, even with the 2" elbow and 2" downpipe, HF cat, 2.25" exhaust. so, 14 psi doesnt seem to far out of the norm.

also, 14 psi is about double what that greddy wastegate is designed for anyway, so you're probably just leaking boost through there. You're probably just spinning the thing too hard, and it cant keep up with the extra air.

thats my two cents, even though i could be wrong.

lets do some math.

14.7 psi for atmosphere + 14psi that you're boosting = 28.7 psi. so lets just say you're making 275whp on a dynojet. 275whp / 28.7 psi = 9.58 whp per psi. 14.7 psi x 9.58 whp = 140.8 whp if you were N/A. sounds about right. so if you boost 10 psi, thats 24.7 psi x 9.58whp = 236.26whp. play with the numbers. i really dont think you're far off.

MC-14

Why does it read so much different compared to the DD. It seems like it's factoring in the atmospheric pressure along with boost pressure...........am I correct? I'm just learning, so any info would help alot. Yea, the wastegate is 6psi, so I actually drilled a hole on the wastegate bracket, and gave it a helper spring under high loads