I was wondering if anyone has had experience with soemthing similar, or if anyone might have an idea of whats going on.

Here is a link to the dyno graphs... "B16turbo dyno" is the folder.

http://photos.yahoo.com/tom_ef3

Setup is as follows:
1st gen B16
ITR intake cam
ITR exhaust cam
2" exhaust
schedule 40 spec manifold
IHI RHB5 on stock boost (8psi according to Auto Meter gauge)
DSM SMIC mounted under hood
greddy type S BOV
SMC
stock PR3 ecu
prelude 345cc (or whatever size they are)

It runs lean, and cannot get it any richer with the SMC.
Power and torque takes a dump after vtec x-over, and never recovers.

I'm very open to suggestions, so if anyone has any ideas, please share.
I am not the owner of the vehicle, I am only helping out a friend, seeing as the vehicle obviously runs very poorly.
TIA

-Thomas

 

 

Few things..

First you need to straighten out that air fuel ratio... What kinda car is this in? You are running extremely lean... I would be very carful even doing any more dyno pulls running like that.. Are you running a hold & peak injector system? or saturated? Are we postive they are 345cc injectors from the prelude?

2nd, Turn Vtec cross-over point back to around 5800rpms, you are loosing big time power having it set at 4700

3rd, Whos driving that on the dyno? once you get some more fuel you need to take that ****** to 8200rpms to get full output.

I think if you clear those things up, you should hit 200whp easy.

God, even that B20 crvtec needs some tunning it looks like 159? what were the mods on that car? stock crvtec's should be well into 175whp...

Jeff

 

Jeff,of course, hit it on the head. Some things I would like to add are:
-switch to larger injectors....DSM 450ccs and add resistors
-think about using the stock B16 cams....the ITR cams are designed for alot of overlap which is bad for a street turbo setup "reversion"
-Get a better exhaust manifold...sounds like you are using a weld el setup which doesn't flow very well
-step up to a 3" exhaust
-make that sidemount a fronmount
-Get a larger turbo....RHB5 works well on D series but dies out on a B16 at the top end

These things I said may not fix your leaning out problem but it will add tons of reliability and some good power to the wheels. Good luck!

 

Well, I was told that the injectors are out of a lude, so thats what I go by. Yeah, I know that the vtec xover is way too low, but even well after the xover, the power never recovers... I failed to mention this is a 1991 civic si h/b with a 1st gen B16, so the resistor pack is allready there. I also told him to get some 450cc injectors, and an FPR, and at least run a test pipe... we are also going to burn a chip with a higher vtec xover.

I likewise was getting worried on the dyno, only thing that kept us there, is that there was no audible detonation present. And we cut the runs off progressively lower, as it made no power that high up anyways... first pull was up to a little over 8k, and it basically fell flat on its face after 7500... so we chose not to beat on it that much. I felt sorry enough for the owner as it was, no need to grenade the thing on the rollers.

As for the B20 vtec, thats my previous motor, and that was on a low c/r B20 (87 octane fuel) with a CTR intake cam, and a full stock exhaust, from the manifold, all the way to my twin rusting tips (1993 integra). Motor sold in favour of a turbo B16...


Yeah, weld el mnanifold is whats on the car... the owner most likely will not make any drastic changes to the hardware, as we believe we are quite far from the full potential of those components... the turbo does seem to be a huge restriction at high rpm, thats for sure. I think he feels that when he gets the most out of what he's got, then he will upgrade hardware such as manifold and turbo.

Also, regarding the underhood mounted SMIC: I made it very clear to him that it does more bad than good under the hood, but I had no influence on the way it was installed, as I was not even present during that time.
Just trying to help him sort his car out.

Thanks a lot for the replies... I dont think there is a point for us to hit the dyno untill some 450's are in there, the cat is replaced with a test pipe, and a program with a higher vtec xover is burned.

-Thomas

 

All good advice given. That RHB5 is gonna be running outa compressor big time.

I could see the log mani exagerating the negative effects of overlap/reversion with the ITR cams, but no direct exp. there. A better flowing mani and exhaust should really show some results.

Id start with bigger injectors so you can put your SMC to work and get the air/fuel sorted out. Get the SMIC some air flow.

 

1 - you need some bigger injectors. i believe the biggest injectors that came in vtec lude's were 310's. they just aren't big enough probably.
2 - get some cam gears and dial out some of the overlap on those cams.
3 - you hit it on the head. that turbo is WAY to small. look at a small 16g, a t3, or hell even a 14b. dropping off after VTEC is mainly probably from the turbo dying. that is why you are seeing power so god damn fast down low. spool up is instantaneous - but the turbo cant keep pushing it out. you would really notice on a hard 3rd gear street pull.
4 - make that sidemount a frontmount. that thing is so tiny, it's not doing anything except being a heatsink.
5 - is that the stock VTEC crossover? with those ITR cams you are going to want to figure out what the best spot for the crossover is and set it there. wherever you can get the transition smoothest is where you want it.

 

Now whats werid is that, if you look at your 2 dynos that are posted, they almost look like 2 different cars. Why?



This dyno shows peak power at 146 at about 7000



This dyno shows peak power at 150 at about 4000, then completely falls off.

So you can tell that turbo is spooling like mad on the second dyno,



compare leed's b16a dyno vs the 2nd one posted. See how much faster that rhb5 is making power? almost 150whp at 3500rpms.. Daves makes 150 around 5500 with his T3, and keeps pulling.

Jeff

 

Whats so odd? That you have a big power drop when the Vtec kicks in? I don't give a ---- if it kicks in at 3, 4, 5 or 7 grand you will always have that drop. This is why I feel the Vtec is only good on N/A motors. Elimidate your Vtec and it won't do that anymore. Because that 30hp a Vtec gives you will hurt you in a 1/4 mile. Yes you start with a extra 30hp than a non Vtec (b16 vs ZC or b18c vs b18b) has but the non Vetc has about 20 lbs more torque! If you run the same turbo and mods the Vtec will get beat in a 1/4 mile. Why because you will lose 30hp for a brief sec. as your Vtec (you 30hp edge) kicks in. this will drop your 1/4 mile time down at least 1/2 second.

 

If you look at the 2 dynos, they are almost identical. Both of them show hp, one shows a/f and the other tq.
What happened is that the 1st one shown, peaked at 146.7hp, so it stayed on a 50-150hp scale, the other peaked at 150.8hp so it kicked the scale up to 0-175 scale, so they appear different, although they show very similar numbers.
Problem is that the hp/tq plot, has both torque and hp in a very similar blue colour, so its difficult to tell them apart.

"This dyno shows peak power at 150 at about 4000, then completely falls off."

You are reading the tq peak, which is not shown on the first dyno...

Either way, both runs made 125hp right before vtec, both drop to a cunthair over 100hp immediately after vtec, and both peak close to 150hp at 7200-7300rpm.
Sorry about the confusion. I can email you the full 1025x768 pics of both runs so you can have a closer look.

Yes, it does spool really quick, and makes 150lbs at 3600rpm.... it feels great, untill vtec and then any excitement that was there is what we feel, prematurely over.
Its very anti climactic.

-Tom