Got the RB25 dyno'd and got low rwhp #'s

[Tripz]

I've got the car dyno/tuned yesterday on a Mustang dyno, and the results seems a bit on the low side. According to http://www.skylinesaustralia.com I should be seeing somewhere between 260-300 rwhp. The results I got is 216 rwhp and 215.5 rwtq and I know this shouldn't be right. The engine is healthy and everything is running quite well. My mods consists of:

95 S1 RB25DET Stock Turbo @ 13psiStock internals Greddy IM w/ Q45 TBFMIC (this intercooler is a little on the small side and I had it for 5 years now)POD filterHKS bovAM-performance turbo elbow w/ 3" high-flow cat, resonator, and apexi'n1 exhaustNismo FPRKOYO rad with two dual pusher fansApexi AVC-Rand tuning with Apexi PFC with Commander

I've went to visit a well-known local Nissan shop where I had my swap done, and the owner agreed it was too low. He had a similar car with a little less mods pushing 260 whp and suggested to me that my intercooler might be too small and old. The shop where I brought my car to is known to have a stingy dyno, but still I should be seeing quite a bit more. Any suggestions on what I should look for or is this number around right for what I have? Thanks!

[Coolwhip]

I've seen dynos of 25's pull more than that on a SMIC.

Got graphs?

[StricNyne]

could be greddy, the TB is huge i hear there is noticible loss in throttle response, i idk tho

[Tripz]

Quick reply, yeah I got graphs. I'll scan them and post them up in a sec. The car runs ALOT more better now, but still too low hp.

[Carl H]

boost leak perhaps?check all couplers, sometimes they are there but you cant hear them.

[Tripz]

Don't think there's any boost leaks. The psi was consistant throughout but it was showing 11 psi on the computer and 13 psi on my boost controller. He said there's an atmosphere difference of 2psi and his computer's set to 0 atmopshere. Just finishing up scanning the graphs, I'll have them up in a sec

[Cpt_Impossible]

Post pics of your setup as well, dimensions of the fmic. Have you taken any care to protect your pod filter from the engine heat? RB's generate a lot of heat and if you had the car idling for a long time before the run that could be killing some of your power.

[Tripz]

Post pics of your setup as well, dimensions of the fmic. Have you taken any care to protect your pod filter from the engine heat? RB's generate a lot of heat and if you had the car idling for a long time before the run that could be killing some of your power.

These are rough estimates of my FMIC (22" L x 6" H x 2.25" W). I bought the pod filter 2 months ago so it's still fairly new, but the filter isnt isolated from the heat. Anyways, here are the dyno sheets plus pics of my set-up.







and the pic of the fmic

[Tripz]

And this is the before and after tune:



The dotted lines were before where as the solid lines are present. The car drives a lot more better now, but still couldn't figure out why it's pushing so less.

[sr240dett3]

216who deffinitly seem on the low side, and on a dyno jet that would be near about 250ish (i believe) .. at 13psi? its werid because i have seen people make near 300whp....

I have a setup almost exactly like yours, but i will be runing a different engine managamant. i have not tuned/dynoed my car yet. so i dont know how much power i will make.

but a A/F at 11.8, what if you try to lean it out just a little bit more, to closer to 12.0 What about timing. what did you have that set to. And also what about plugs and other ramdom stuff?

well what ever you do, please keep us updated, and good luck !!!

[Shocker]

hmm check your compression...

[lucky7]

nearly the same set-up as you, running 15psi, i made 305hp and 315 torqe.....on a dynapack.

[Tripz]

Yeah, that's why I find it strange. I'm gonna check for exhaust and boost leaks tomorrow and hope it's something simple. The plugs were changed within 2 months ago with NGK copper plugs, plus frequent oil changes as well. I'll do the compression test this weekend and see what I get outta that, what number should I be seeing from a motor being at that age?
Modified by Tripz at 10:11 PM 6/14/2007

[DriftingisLame]

Maybe your timing is really retarded?

Compression numbers should be even above all. I get different numbers everytime I use a different compression tester... Or if I do the test slightly different.. if all your cylinders are within 5 psi from each other, but you get all really low numbers, its very unlikely that they all have evenly sized holes in their pistons... Know what I mean?

[HxC_Nismo]

so did you find out whats up with the low numbers i check your timing and also to a compression test and see if you have a dead cylinder cause the numbers your putting out look like rb20 numbers, my stock rb26 s14 put down 307 rwhp and 273 rwtq on a dynojet at nopi in st louis so good luck with diagnosing the problem, and keep us posted on the progress.

[Tripz]

Thanks for the replies guys. I'm going to do the compression test tomorrow and also seafoam the car to see if I have any exhaust leaks. My intercooler is around 5 years old, and it has taken quite a bit of punishment from the weather we get here. Should I be worry or even considering getting a bigger and newer one?

[catch221134]

The good and bad thing about the AVC-R that you are running is that it will actually compensate for boost leaks. My roomie has one, and he put the boost leak detector on his car and had one major one around his BOV. The avc-r corrected for it =) Its still better to have it completely sealed though.

[Tripz]

Thanks for that information Catch. Now I've just finished doing a compression test and got fairly low numbers (I THINK?). Counting from front to back:1. 130 psi2. 128 psi3. 130 psi4. 125 psi5. 130 psi6. 127 psi

It was done on a very warm motor so it should be fairly accurate. Are these numbers I'm seeing okay? They're quite even throughout the cylinders, but are the numbers too low? Additional information:

Sparkplugs: BKRBE-11Roughly 130 xxx km on the engineTiming belt done @ 81 xxx km

Haven't had time to check for any leaks, getting a little late and don't wanna smoke up my neighborhood and scare everyone. Thanks all!

[captainclutchkick]

correct me if im wrong guys , its been awhile since i comp tested my 25 but i believe you should be in the 170-175 range man!

[300Plus]

177psi across the board here ... not looking good man

[Tripz]

Ah damnit! Gotta bring it into the shop then. What's the worse I can expect? A rebuilt?

[eh?]

Redo the test with another gauge and make sure you are holding the throttle open. With numbers like that i'd be wary of the gauge.Also a leak down check with give a better picture.

[CoupedUp]

Yea, ,ake sure the TB is open and with consistent numbers like that, id be wary of the gauge as well.

[Tripz]

Thanks for the replies, I'm going to get a new gauge today and double check to see if my TB is wide open. I'm also doing a leakdown test, I'll post my results when I'm finished

[Tripz]

Okay, done another compression test today. I got a new gauge and got:1. 140 psi2. 140 psi3. 140 psi4. 140 psi5. 144 psi 6. 140 psi

Is this a fairly good number? Ideally I want it near 175psi all across but should i be concern? When I got the motor 2 years ago, it was also 140 psi all across.

I also used the old gauge and got the same numbers. I think last time I didnt open the TB all way so thats why my numbers were low. I also did a leak down test but had a hard time getting the cylinder to TDC by cranking it. Anyone know the size of socket I need to manually crank it? I tried 27mm and it was too small.

[Tripz]

A little update:

Just brought my car into the muffler shop today to have my cat remove because it was shot. I removed it and replaced it with a 3" piping and it should improve the power significantly. I also found out that it was 3" throughout until it came to the resonator where it was 2.5" in and out, gonna get that removed as well tomorrow and I'll post my dyno results again. Also for those who have the AM-Performance elbow, where do you think I can get a gasket for it since mine is leaking a bit. Thanks!

[Shocker]

might have to go to autozone and get a sheet of exhaust gasket and make your own... not exactly sure what your pattern looks like im guessing the 5 bolt deal.

But it might actually save you money and time. I did it for my q45 TB gasket. 5 dollars in gasket maker and 5 minutes later good to go.

[ATpossible]

try 30mm. i heard its either 27mm or 30mm. mine was 30

did u try a wet compression test? numbers usually always go up since it helps the rings sit better and compression goes up around 5-10psi or so.

leakdown test would be better but a little more work.

good luck...

[Tripz]

Thanks, Ill try 30mm. What is a wet compression test, how is that done?

[Tripz]

BUMP! I've got my car dyno'd again with a new turbo set-up. My timing is very advance (30 degrees), and I heard that 20-21 degree should be very good for the rb. The reason why I have the timing so high is probably due to the fact that when I changed out my valve cover, and when I went to install it back I totally retarded the timing on the CAS. Wondering what's everybody's timing on WOT.

btw, car made 370 rwhp and 282 rwtq on a mustang dyno at 13.3 psi.