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I really want a safe tune, and right now i am getting a little bit of backfire, i have 8degrees timing and 48psi at idle with vac line on, what should i set it at so that i am safe and i only have a 255lph intank no inline yet. so what would be totally safe so that i can run it at the track.
thanks, combo in sig
Not really sure what car you are referring to, but, it seems like you are talking about that '89 with the procharger, hence this is a procharger site. Do you have a boost retard of some sort? Even w/o a retard, i would set the timing to 10 degrees. What injectors are you running? I would set the fuel pressure to 45psi or so vac. off for now. Are you running an fmu? To really get a hand on things, gonna need to know a lot more.
Sorry about that, i thought i had more in my info, i have stock ignition, but msd coil, no btm, no timing retarder, or anything like that, pretty much stock. no fmu, and 42# injectors with a pro-m 75 cal 42.5 SC. i really want to run safe here, for now, i dont care if i lose a few horses i just want to feel her out and wait untill i get an intake and a tune, along with a hi-6. i am going to pussy shift it at around 5800. at most. before i heard of procharger power i could really only get a hold of vortech guys and there opinions were really different. for now i am considering dropping fuel pressure to 44 vac line on.
thanks, David
With the 42's and the right MAF you should be safe. Set the base FP to around 44psi at idle. you should really have it at least hooked to a wide band to make sure its safe, and you will really benefit from some dyno time. If running the ATI intercooler you should be ok with 10 degrees of timing but make sure the balancer is good!
Setting the fuel pressure with the vacume line on does nothing... that is CONSTANTLY changing with ambient temp., underhood temp. and so on. The only accurate way to set fuel pressure is by taking the vacume line off at idle to see what the fp will be at WOT.
With that aside, since you have an intercooled setup, 10degree base timing should be just fine, maybe set it to 9 to be safe, but 10 should be okay. I would set your fuel pressure to about 48-50ish to be on the safe side (again... not with the vacume line on, that is not the way to set fuel pressure) till you can get it on the dyno to see what is happening. Be especially carefull for detination, listen for it the best you can for now. You have a leg up on how your car runs because you have long tubes. With long tubes, your car is autmaticaly going to run richer unless tuned otherwise with a chip (and even in that case, a N/A chip comes right out when you throw a blower on) because the O2 sensors are moved so much further away from the combustion chamber, they don't read how they were origionaly callibrated to read. Not too many people know that... thats why some people will argue that LT's aren't worth hardly any power... because unless you get the a/f back to where it was with shorties and should be, you are drowning out any extra power you should have (and you WILL have when tuned properly).
Good point Don, I have heard that about long tubes for quite awhile now, but I never related it to the small, if any power gains that people are showing.... Some people actually have major problems because the 02 doesnt heat up and never reaches operating temp and the car ends up running like total crap. I've been wanting long tubes for awhile now but I haven't done it yet due to the install in an SN95 car and then with the 02 problems maybe I'll keep the shorties...
My car was the poster child for O2's not heating up enough to even register. Right off of the bat, my car ran pig rich... I did however notice quite a power increase (because for some reason, my car LOVES running rich). When Don Walsh tuned my car, he was having a really hard time getting it to end up right... by the time he actually got the O2's heated, the car was super lean, so it wasn't worth it. He tuned my car in Open Loop... kind of his 'test car' so to speak with a complete open loop tune. To this day it is (till I finish the rest of the blower install... started yesterday, I have a LOT to do). It's funny... I call it the carb. wana-B car... The ONLY changes it makes are from the MAF... he has it so incredibly tightly tuned (he spent TONS of time on it) that it doesn't need the O2s determining the adjustments to the fuel tables, only uses the MAF, AIT, and MAP for minor adjustments... car is extreemly predictible, it's great. I personally love it, but that is all going to have to change with the blower tune I'm sure. He was able to pull almost un-heard of power gains out of it before... hopefully (most likely) he will do the same again.
Wow! thats interesting....I can only imagine what a pain a blower car will be to tune if I put the long tubes in..... So do you know Don Walsh personally or was he just who you chose to tune it? Is he using the Autologic Chip system?
I've known him for a long time... long before he did any kind of tuning, had a shop, or had a race car. He'll make the car work right, I have no worries... I am 99% sure that the car won't be run in open loop anymore, so it'll be a different story. Yes, he uses autologic chips.
Glad you like donnie, and think he does good work hopefully he can get more than 454 out of my combination.