dizzyj

I've been working on the car in my avatar for ~3month now. and I think I'm down to just getting the tune, and I'd like some advice that I could not find by searching.

as an fyi, I've read tons of threads with great information about diy tuning, I've read all the tech pages at lr..etc

I'm tuning a 2.5l turbo with:
k27/8 turbo
LR maf (stage? dont know)
3" straight pipes (although I need to put a muffler on)
I dont know which injectors I have, they are black, not green (I will find out).

The tools I have to tune with are:
- a working wideband 02
- an adjustable fuel pressure regulator
- a power perfect maf tuner that have successfully connected to with my laptop.

I believe there are no after market chips in the dme.

so what I am trying to do is to program the output of the maf to match the transfer function the dme expects using the piggyback.

first, is there any way to test/record what the transfer function of the maf is? just to prove it was in good working order I wired up my volt meter to the output of the maf and blew into it. I could get it to only read 1-2v. would that be normal? I guess I dont know how much air actually flows over this at full boost.

here is what I was going to do:
- current fpr is set at 40
- when warm, idle is rich
- rev to 2k is lean >14.7
- rev to 3k is lean low 14.

at idle, I cannot give less gas via the tuner, only the fpr right? so I was going to back that down a bit to get my idle where I want it.

then start using the ***** to increase the amount of gas at each rpm hitting my desired af value. after a few iterations of this, I should have a pretty decent map.

my concern really is that the input voltage will only go so high, that it limits me to a small range of used cells in the mapping, and only 1 or 2 pots to use.

thanks as always

lart951

power perfect is a very primitive and limited piggy back, once you adjust the ***** you need to upload the adjusted map from the piggy back to your pc, than you need to manually match the previous a/f ratio setting to the new map, save it and downloaded back to the piggy back, I dont know how many times I did this when I was tuning my car years ago, you need something newer or at least more flexible. I know someone who has a mafterburner

CDH-CTT

I have just about the same set up you do( my 27/29 with #8 and 55cc injectors are not installed yet).... I have been playing with the first 2 POTS and testing(26#6 and a few LR bolt ons) its kinda wierd to setup on the comp I still dont like the way it works(compared to Zytec, EFI Live, and HP tuners) but it gets a good base line then you just tune the *****( or at least I do) to get the fine tuning.....I only got it cuz it was cheap and from another RLer.... mine I had to mount, it was in the pocket under my radio but if I hit a pot hole hard it would kinda geek out for a sec.... mounting it close to where you can see it helps with the ease of tuning a lil while driving....
How does that 27#8 drive?? is it laggy??
Good Luck with the tuning

dizzyj

I havent really driven it yet, for fear of detonation without a proper tune. I'd say its pretty laggy, the boost (the one time I tried it) kicks on at ~4k. Seems a little high even for that turbo. WHen it kicks, it kicks like a mule tho!

what maf do you have? and out of curiosity, how many lights are lit up when you first feel the boost kick?

CDH-CTT

Its an older LR MAF..... the 0% light is on with Key ON engine OFF, then idling its a the first light above 0%, when boost kicks in(i can check again tomorrow) i think the 3rd light lights up....I know I had to adjust the #2 pot for lil more fuel cuz it was leaning out....but when the car is cold and the outside temp is cold I can pull it back some but when its summer here(Az) I turn up the fuel a bit...

CDH-CTT

doabarrelroll

Lart, you scooped up that Mafterburner before I could! You got it for a steal, literally... :P

black944 turbo

Do yourself a favor and get rid of the power perfect and going with something different. I had this setup for a few years and could never get it to hold a tune. Lart is correct with the way you tune it, very slow and very tiresome.

gpr8er

Or you could enter the new century...www.roguetuning.com

dizzyj

I actually have an ostrich 2.0 on order, but my understanding is that I would still need a piggyback to convert the maf to afm signal

gpr8er

really, just bite the bullet and go for the M-tune. Install it and forget it. You will live in the world of perfect a/f ratios and not have to worry about setup of old world tech.

CDH-CTT

Yeah I like that idea..... maybe when my other engine is complete I'll run an M-Tune...