$OD With 2 Bar MAP/Turbo - questions and observations

[1BadAction]

So I'm back in the obd1 world on a new rig, and decided to slop together a single small turbo kit with iron manifolds and TBI. I know there are some issues, but there are also some benefits. 7-10 PSI shouldn't be tough to do non-intercooled with the heat removal properties of the wet manifold, AND it's exceedingly simple. The goal is just to have enough power to keep up with traffic because, well, the TBI 350 is anemic at best. I have everything I need minus the injectors (which I am working with a friend who flows injectors on) and the tune. So first off my question.

Any solid Boosted XDFs out there for $OD? I have one for $OE that's pretty good and I can build a boosted OD XDF if necessary, but if someone has already done the work, then that's easier.

Also, I have went through the tunes on these things and read where people have problems with them when using a 2 bar map, and I think what I have in the following screen cap is about the only thing you can't tune around. The ECM at startup is looking for a particular voltage from the map and bases these tables on that, and since it's looking for the voltage not actually the KPA, it will skew to the high altitude side error side of these tables. It looks like to me if you eliminate the high altitude correction factors, and build the tables with the pressures that correspond to a 2 bar, there shouldn't be too much of a problem.

Look at the BPW/Altitude vs Vacuum in particular. It would vary the BPW all over the place and have a normal person chasing their tail like a MF!

16779

[1BadAction]

Also, I'm running an E-trans, so no getting away from the 7427.

[dave w]

Several years I ventured into researching a TBI boost application: http://www.gearhead-efi.com/Fuel-Injection/showthread.php?501-PCM-Options-for-Supercharged-454-4L80E

Hindsight being 20/20, I would recommend using a Dynamic EFI system for boost: http://www.dynamicefi.com/EBL_Choice.php

dave w

[brian617]

This guy did it couple years ago, might look through his post to find some good info.

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?5274-Tuning-large-injectors-Siemens-Deka-80-lb-7427-0E-Turbo-383-MPFI&highlight=7427+turbo

[1BadAction]

I'd love an EBL but I'm not going to buy another ECM just to go through the headache of piggy backing the factory one to get trans control.

I forgot to mention... I'm going to run an external regulator with a billet injector pod and a pair of Bosch 210s, which should be pretty interesting tuning by itself.

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[dave w]

The option to use a 2 Bar MAP with the '7427 is a good option, not a better option, or the best option.

dave w

[1BadAction]

The option to use a 2 Bar MAP with the '7427 is a good option, not a better option, or the best option.

dave w

"good option, not better or best" is pretty much the theme of the whole truck. LOL.

I'll give it a shot and see where I land, and I'll post the XDF and ADX for everyone else when they're done and confirmed working.

[1BadAction]

This guy did it couple years ago, might look through his post to find some good info.

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?5274-Tuning-large-injectors-Siemens-Deka-80-lb-7427-0E-Turbo-383-MPFI&highlight=7427+turbo

I looked through pretty much all of his posts, seems like after getting the data right he did ok, but ended up smoking the motor anyways. Not sure why.

EDIT: JUST found a thread I missed from him, looks like an XDF tune and ADX was posted. This will give me something to chew on for awhile!

[1BadAction]

I ended up keeping the stock injector tree for now, with a 28-32lb spring and an Aeromotive Stealth 340LPH pump. They're running at a hair over 28psi so I have the injector size setting at 90 LB/HR. So far there are no ill-effects from running this pressure, the injectors aren't leaking, it's not running overly rich, etc.

The VE needed about 10 numbers knocked off of it and my WOT duty cycle is about 45% with PE active. This gives me some overhead power wise. AE needed to go leaner on tip-in and richer on a WOT stomp (I assume) due to the wide open intake elbow. I got it to where there's no bog or dead spots anywhere but I'm not getting too involved since I'll be building the hot side sometime this week. I expected it would be some work to get the 2 bar up and running correctly, but there were a LOT more altitude modifier tables than I had expected. Pretty sure I have all of them where they need to be since my driving around the last couple days has produced no weird quirks in the tune like it did initially.

[brian617]

I'm also running about 26 psi (best I can remember) with TBI 7427. VE wasn't too much trouble mostly AE stuff even the fuel adders PW for AC clutch needed work.

[PJG1173]

I also used 96lt4c4's adx and xdf. been running $0D/4l60e with boost for over a year now. I'm curious what altitude modifiers you changed (the pic is too small to read on my system). I ended up zeroing out most of the tables in my tune that referenced baro.