I've got a couple of questions re my setup...

[BoxheadTim]

First, I'd like to point out that I bought the car this way so the mods I know about are either based on what the PO told me or what I've found out in the meantime.

The relevant specs as far as I know are:

• FP Green "spec" turbo (I have a suspicion that it's not an original FP one as it doesn't have the FP plaque on the compressor housing, but I might be wrong here)
• 660cc injectors (make unknown) running at approx 42psi (the fuel pressure gauge has a major case of the shakes between 40psi and 45psi when the engine is running, I assume because it's not damped).
• Large FMIC
• Fluiddyne radiator with one 12" and one 11" fan
• ECMLink v3
• Modded (OEM or Evo 3) exhaust manifold (someone welded a wastegate connector directly to the manifold)
• 3" downpipe and exhaust

It's running what looks like a fairly basic map - ie, adjusted for the injector size, but ignition timing and injector settings are untouched otherwise as long as the engine parameters stay within the MAF clamp area.

I've got various issues with the car, namely knock on light load at certain revs, plus it runs rather hot under constant mild boost (5psi) uphill. I've seen water temps up to 245-250F on the data logger on a hot day (90F+) before I could pull over under these circumstances. Given that I live in the mountains, that's a bit of an issue.

Anyway, I'm trying to track down some of the issues in the hope of getting the car on the road before winter, otherwise I'd have to sell it and buy something that works .

First question:

The car runs a 3" GM MAF instead of the OEM one. My understanding is that the OEM MAF needs the baro and IAT sensors to determine the correct airflow, whereas the GM MAF w/ MAF translator will keep the baro and IAT constant as its output doesn't need correcting for either. Or am I mistaken here? However my understanding is also that the ECU retards the timing for high IATs, does that mean a 'safe' map needs to take this into account and run some slightly retarded timing?

Second question:

From reading up on both the turbo and injector sizes, I have the suspicion that I have too much turbo for the injectors I have. This might explain why the boost is currently capped at 14.6psi and TBH for the intended use of the car (daily driver with some track/HPDE use during the summer) I don't necessarily need the big numbers that you can get with an FP Green. I also don't need to blow up the engine, either. So, would anybody want to comment on the size of the injectors in relation to the size of the turbo?

Third question:

The GM MAF is currently in the position of the stock MAF, where its connector vies for space with the coolant overflow tank. Am I correct that this is not necessarily the best or only position for it and I could move further down the intake (ie between the FMIC and the throttlebody) without any negative effects?

 

[MaKaPhiLLy]

As for the 3" GM MAF it's supposed to be between the bov and throttle body on the upper straight part. If your running blow through. As for the other stuff idk about that. Im a newb but good luck with the car welcome to dsmtuners!

 

[crusada]

Yes run the GM maf after the Turbo before the TB that could be causing alot of issues with the ECU being im sure your running a blow through instead of a resirc. As for the injector size if thats a true FP green i think its a little much for what your running. A 20g would be quite nice for that setup and probably put you at the numbers you may want just my opinion. I would be sure that ## fans are kicking on with the heat issue. I would suggest maybe wiring the fans so they are on all the time or put them on a toggle. Just a suggestion. The boost being caped you never said if your running a boost controller. If not that could be what the WG is set for. just my .02 maybe im wrong on some of it if a Wiseman would like to put some advice thatd be great

 

[BoxheadTim]

Thanks for the comments. Just a little clarification:

• The fans are coming on as they should. For some reason the car seems to suffer from what I'd consider insane underhood temperatures (if you've driven it for, say, 20-30 minutes the valve cover gets so hot you can barely touch it, even if the coolant temp is somewhere around 210F). This might simply be the heat from the big turbo that soaking into everything that's in the engine bay, though.
• I had forgotten to mention that the front part of both wheelarch liners has been removed - my suspicion is that this will allow air to flow past the engine bay rather than through it, which is unlikely to help my cooling problems.
• There is no separate boost controller, the boost appears to be controlled by a combination of the OEM BOV, ECU control mechanism and a large Tial wastegate that's hooked up to the aforementioned flange on the exhaust header.

I'll have a look at exactly how the GM MAF is hooked up (ie, is it hooked up via a MAFT or via the ECMTuning cable) and see if I can move it without having to change too many things around. I'm also hoping that I can hook up a more accurate water temperature gauge this weekend as the stock gauge seems to mainly serve as an indicator that tells you that the engine is already getting too hot.

 

[DeadlyScone]

so what size injectors should i run with a FP green? say if i wanted to run about 4-5psi more also?