New to the B15 scene, any advice?

[condor14]

Hi guys,

I just got a 03 Spec yesterday, 41,xxx miles.
Engine is somewhat freshly rebuilt (I was told a previous owner was running 20psi with stock internals )
Bored .10 over
wiseco pistons, rest of the internals are stock
currently boosted at 5 psi
JWT ecu
header to 3in full exhaust
I know the fuel pump, oil pump, and injectors are not stock. I can't recall the brands.
Full aftermarket suspension, again I cannot recall the brands.

I was told the engine is making 300hp with the current setup, not sure how accurate that is, but I won't argue until I get it on a dyno. lol

Idles high when warm. just under 1500 rpm, surges to 2000... was told this is from the ecu and is normal. (research is also telling me the same) I would like to find a way to at least bring the rpms down, but from what i've heard I may be SOL unless I put in a different ecu.

I plan on using the car as a driver during the summer, maybe do a couple track days here or there.
I may do a full engine overhaul during the winter. (Wanted to build up an s13, but found this instead)

As I understand, the main problems with the QR are the weak connecting rods, butterfly screws in the intake and exhaust manifold with the pre cat. (don't have to worry about the last one)

If anybody has any advice or tales of caution that would help me get the most out of this awesome ride, please do not hesitate to pm or reply.

I will try to take some pictures after work tomorrow for those interested.

[AZhitman]

Welcome aboard!

Congrats on the new ride. I've got several concerns based on the info you provided, but not much time to go through them all tonight... I'll let some of the other experts chime in first and check in tomorrow and see where we're at.

Did you get receipts or any paperwork on the engine build?

[condor14]

There are some receipts and paperwork in the glove box. The engine was rebuilt by a professional mechanic. He bought it with the blown engine and rebuilt it on his own time. The owner before him did all the mods, from what i was told.

The car itself is super clean, so even if the QR takes a dump, I would not hesitate to do a swap to something more reliable. I have the resources, the time, and the inclination to do so. (Plus, i know some people)

[AZhitman]

I'm gonna go out on a limb here and guess that engine isn't .10 overbored. As far as i know, the largest pistons readily available for the QR are .040 over.

Perhaps he meant .010 (which is basically just a rehone - cleaning up the bore/sleeve - like what you'd do when doing a stock engine rebuild).

We'd need to know what injectors (cc) are in it - that's kind of a big deal. Need to know what tuning was done, or if it's just a generic JWT base tune. The idle problem could be symptomatic of a bigger issue, OR it could just mean someone got lazy and didn't dyno tune after the build. Really, at 5psi, there's almost nothing needed. Most stock ECUs can adapt to mild boost.

Need to know what the turbo specs are - that's also a big deal.

[condor14]

Injectors: 440cc
Turbo: A/R 88mm Precision Turbos
stamp #447534

Pretty sure the tune is the stock JWT tune

Also, my bad about the bore. I meant .010

[condor14]

I'm gonna go out on a limb here and guess that engine isn't .10 overbored. As far as i know, the largest pistons readily available for the QR are .040 over.

Perhaps he meant .010 (which is basically just a rehone - cleaning up the bore/sleeve - like what you'd do when doing a stock engine rebuild).

We'd need to know what injectors (cc) are in it - that's kind of a big deal. Need to know what tuning was done, or if it's just a generic JWT base tune. The idle problem could be symptomatic of a bigger issue, OR it could just mean someone got lazy and didn't dyno tune after the build. Really, at 5psi, there's almost nothing needed. Most stock ECUs can adapt to mild boost.

Need to know what the turbo specs are - that's also a big deal.

Sorry about the double post, but here are the specs on the injectors and turbo, again. Thanks for your time.

Injectors: 440cc
Turbo: A/R 88mm Precision Turbos
stamp #447534

Pretty sure the tune is the stock JWT tune

Also, my bad about the bore. I meant .010

[SoundEfx]

Congrats on your QR purchase.

If this is your project car that you'll have for a while, this is my advice.
Convert it to an 04 - 06 spec-v. You'll need ecu, gas pedal and other stuff and the reason is this.
You'll have alot more tuning options, including osiris from uprev that will allow you to tune your car without having to ship the ecu to your tuner.
There is also the Nissan Data Scan program you can use to perform your idle reset / relearn if that is the cause of your high idle.

Also, a 2K idle is NOT normal. It might be on a race car, but not a daily driver. You either have a vacuum leak or you need to reset your idle.

Another common issue with the QR are their 'butterfly' flaps. The screws tend to come loose and gets 'eaten' by the engine. Put some red loctite on them to be safe.

[condor14]

Congrats on your QR purchase.

If this is your project car that you'll have for a while, this is my advice.
Convert it to an 04 - 06 spec-v. You'll need ecu, gas pedal and other stuff and the reason is this.
You'll have alot more tuning options, including osiris from uprev that will allow you to tune your car without having to ship the ecu to your tuner.
There is also the Nissan Data Scan program you can use to perform your idle reset / relearn if that is the cause of your high idle.

Also, a 2K idle is NOT normal. It might be on a race car, but not a daily driver. You either have a vacuum leak or you need to reset your idle.

Another common issue with the QR are their 'butterfly' flaps. The screws tend to come loose and gets 'eaten' by the engine. Put some red loctite on them to be safe.

Thanks for the reply!

I'll look into doing the conversion. That seems like something I would have fun with lol

Can I use NDS with the Jim Wolf ecu, or do I need to convert to stock? I tried to find info on that but came up with nothing relevant. Maybe I just need a class on how to use search engines effectively, i dunno

I have not been able to find a vacuum leak.


I did run live diagnostics with an OBDII scanner and saw that the fuel system would go from CL to OL-DRIVE during the idle surge.
Then it would go into closed loop and the RPM would drop. Back to open loop and the RPMS surge again.
THIS ONLY HAPPENS WHEN THE ENGINE IS WARM. Cold starts give me an idle around 1k, then instead of dropping as it warms, it starts to climb until it sits just under 1500. Once the engine is at operating temperature it starts to surge.

I KNOW that 2K idle is not normal for a street car. I said I was told, and from my research on Specs equipped with the JWT ecu, this was just how the JWT ecu causes the car to idle. Perhaps, not as high or as great of a fluctuation. Then again, this car does have larger injectors and fuel pump than stock. My thinking was more fuel = higher rpm. If the ecu was not tuned for the larger injectors and pump, it would run richer. Correct?

The surge is very consistent. It is too consistent to make me think there is something wrong with the engine. Seems to me that the tune is the problem, but I am by no means an expert on tuning, turbocharging, or cars in general. I am merely a man with a new ride and an urge to fix everything that doesn't seem right.

Thanks again!

[SoundEfx]

I never had a JWT ecu, so I don't know how it interacts with NDS.
I do know that NDS does not reflash the ecu, so you're safe to use it with an uprev flashed ecu.

Talk to jwt and see what they say about the high idle.