I'm still struggling with a 35R running a 4" inlet pipe. I've tried searching for answers but, surprisingly am not coming up with anything useful. Here's a run down on what's been done so far:

1. RE-built bottom end, still 2.0L
2. 280 cams (forget the manufacturer as they cam with the car)
3. stock valvetrain
4. OEM intake manifold and TB
5. RNR tubular exhaust manifold with 35R, TBE with straight pipe
6. LICP and UICP with aftermarket FMIC
7. Some no name 4" aluminum inlet pipe
8. MAF sensor (for now) with HKS cone filter
9. I removed the 880s injectors in place of OEM 560s just to get the car to idle for now

Oddly the car will idle at open loop warm-up but, once into closed loop it really struggles.

I've backed out the MAF screw, making it flush internally. I've played around with the timing at idle but, to no avail.

I'm going to adjust the idle sensitivity tables and also play with the BISS as well. Obviously the MAF needs to be scaled but, without the idle trim/O2 feedback adjusting I can't tell which way to go with the scaling, although I'm certain the ECU is dumping fuel so I would need to reduce the scaling to bring the afrs in check, which are retarded rich (even with the OEM injectors).

Any suggestions would be great, especially from those that have experience with a setup similar to this (mainly the 4" inlet pipe).

I plan to switch the car over the SD but, want to get the MAF ROM tuned so that switching to SD is that much easier.

Thanks as always.

 

All the stock MAF 4" pipes I have done have been a pain. Tip in issues, idle issues, etc. My suggestion would be to do a 3" get your tune (spark primarily) then switch to the 4" pipe. The AFRs going to need to be revisited when you switch to SD anyway so while you want the scaling and table close, no reason to worry about it 100%.

 

It is exactly for your kind of setup that I planned the SD conversion.

I would tune for SD right away, set your fuel map to the AFRs you want to see and keep the timing cautious until the fuel and boost is done. Aim to have load = MAP (kPa) on full boost in the midrange, adjusting the injector size and VE tables to make your wideband equal to your fuel map (plus any lean spool effects).

 

Thanks guys. I'm going to put in a 3" hard pipe for now to get the car dialed in at least a little than make the switch to SD (waiting on the customer to buy the map and IAT sensors).

JCS - the SD stuff is awesome man, great job. I know alot of guys had said so I just wanted to let you know again. I've done a few dozen SD cars so far with all great results.

 

this baby is crying out for SD

 

maf scaling needs to be fixed. I had a similar issue, although not as bad as you describe, with my ets 4" intake.

 

Yeah I know the MAF scaling is off but, dropping scaling by up to 25% at idle made no real change.

 

Every time I post something about the pressure drop that occurs because of 4" intake pipes and the MAF...I get slammed. It does happen though.

The following will fix the pressure drop and allow you to get smooth MAF readings and you will lose nothing from doing it.

Put a 3" rubber coupler onto the MAF and insert it into your 4" pipe as you normally would. you will smooth the flow after the MAF and allow it to read nearly perfect.

Give it a shot.

Paul

 

Oh no man, your definitely right about the pressure drop as I've encountered this on every 4" inlet pipe I've ever come across. This particular car is just giving me a lot of headaches, more so than usual.

I like your idea though, pretty ingenious. So you take a 3" coupler and just place it over the end of the MAF than slide the 4" coupler over the 3" coupler to attach it to the 4" inlet pipe. Huh....

I wish I would have thought of that earlier as I've already pulled the intake manifold and welded a bung on for a GM IAT (MAT) sensor to convert the car to SD

 

Heck, give it a try. It does not take too much time to put the coupler on and go for a test run. You might like the results.