FAST questions

[540Malibu]

i found my way to the turbo buick site (Turbo Buick.com....go figure) anyways, Im gonna buy the FAST setup for my big block and was looking for advice on what it should have, heres a list of what i got and what i need, hopefully craig or any of you other guys can send me in the right direction. Its a gen6 Chevy block (actually 533ci) it will have 325cc runner AFR heads (when they send them to me) 9.3:1 compression, all forged. I am going to run either a d2r or f2 procharger on it. the cam will be roughly a 246/256 @.050 .632 lift 114 lobe sep. i havent piked an intake yet, the motor will not see above 6500rpm. Heres what i need WB 02 is a must, Im not sure if it needs to be sequential or not, and im not sure if i need the IAC provision, i was hoping you guys could help me out with those, This thing will be driven on the street a few times a week and once in a while to the track (and hopefully back) i was planning on 95lb injectors and a ford style t/b (seems as though it would make more power) Im not sure how much boost i am going to run yet, would a 3 bar map sensor work alright with only 10 lbs to start with? i dont need individual cylinder control either. thanks for the help

 

[bobc455]

540,

IAC control is nice. I don't know what the Ford TB is, but if has an IAC motor, I would recommend using it. Otherwise cold starts can be a pain.

If you are gonna be running over 15 # of boost, then go ahead and get the 3bar sensor. If you are gonna stay with 15# or less, then a 2-bar will give you better tuning resolution. Are you gonna intercool? The 3-bar will work with 10 pounds of boost.

Sequential will give you a tiny bit better performance, but it is expensive. However it sounds like that is gonna be a very healthy cam, so sequential may give you a bit better drivability. Remember that with sequential, you will need a cam sensor (something not often provided for on big-block V8s).

Actually I wonder if you are going to have to run in alpha-N mode with that cam...

Either way, when you get it together, let me know and I'll be happy to help you tune- I'm up in Amesbury.

-Bob Cunningham
bobc@gnttype.org

 

[NoSlix]

Actually, that's a small cam for that sized motor. It will run in true speed density mode without problems. The ford style throttle body is much easier to plumb for so I'd go ahead and use that, although you will need an adapter(part #30-7022) for the IAC. The IAC will make cold starts easier and also allow you to idle it at a lower rpm if you have ac, powersteering, etc. I've seen a few people use 95lb injectors with b2b units, although the idle tends to wander a bit.

 

[540Malibu]

sounds good

ive read that i can use the accel DFI distributor with the FAST setup, i really dont wanna buy a distributor and then snap the tangs off of it, and i think i saw that the accel dual sync gadjet, has LED's for very easy phasing so i wont need to spend alot of time setting it. I have a new silverado with the 496 in it and it apears that they have the cam sensor setup in the distributor hole so it can fire the 8 coil packs, i dont wanna go that fancy with something that should be simple like ignition. Im used to running carbs, so only 3 things could go wrong, no fuel, no compression, or no spark, this whole efi thing adds a whole bunch more complexity when somethings not workng right, but i think it will be worth it. I will be running an intercooler on it after i get it running and tuned without it. The cost isnt really all that important, i'd rather do right and do it once, then get something and then have to do it again later. im running that cam profile cuz i think it should build alot of torque, and this car all said and done will probly weigh 3800 with me in it, also running 3.55 rear end gears, im counting on tourque to get me off the line rather than high rpms the car will have a gearvendors unit on it for some extra fun. I aming for an 8 second true street car, traction will be the limiting factor, but the efi and the blower should help me out with tuning alot.

 

[mosk]

FWIW, I have a FAST bank-to-bank on my turbo Toyota truck, and I run a Ford TB with the GM IAC motor. A couple of firms make adapters to adapt the GM IAC motor to the Ford TB. I personally like the one piece billet adapter made by Precision Turbo (http://www.precisionte.com/). It runs about $50 IIRC, and works great for this application.

You can sort of see the GM IAC motor and adapter at the bottom of the Ford TB in this picture:

If I can get this combo to work on something as off-the-wall as my motor, it should be a piece of cake on your setup.

Jeff

 

[NoSlix]

Malibu,

You can use the Accel dual sync distributor. I've used it before and it works well. You'll have to order the FAST marine unit, which is set up to work with the Hall Effects signals of that distributor. One thing to keep in mind with the distributor providing the TDC reference of every cylinder is that you'll always have a couple of degrees of scatter due to the harmonics of the valvetrain and oil pump.

 

[540Malibu]

with the blower on the motor i dont want the timing to move any more than it has to, is there a distributor that i can use with a crank trigger that I wont have to modify to get the cam signal?

 

[Craig Smith]

If you are looking for a cam signal out of a distributor and you already have a crank trigger, your best bet really would be to knock 7 of the 8 tabs off the pickup wheel inside the distributor. Set it up so the cam sensor triggers around 70 to 80 BTDC and it should work well, and it's really not too tough to do. You can even buy a replacement pickup wheel out of the Jeg's catalog if you ever wish to return the distributor to its original form.

Another thought along the lines of your first post is that with a blown 540 you could probably run a bank to bank setup and not lose much, if anything. You wouldn't even eed a cam sensor at all then. The only time the bank to bank setup an give you trouble is when the pulsewidths get very, very small at idle. With that big of a motor, plus the drag of a blower to boot, I don't think the pulsewidths are going to be small enough at an idle to create any problems for you. No guarantee, but it's a guess based on education and experience.

Hope this helps.

 

[NoSlix]

Craig,

You really don't HAVE to run a cam sensor to run sequential, though do you? Wouldn't it only be an issue with individual cylinder correction? I'm sitting here trying to find a real reason to have one other than that. I would think that without a cam pulse, and I may be off base here, that the unit would pick the first cylinder that's pulsed to be #1 and go on about it's business after that. Or will it cause an error to not see a cam pulse?

 

[Craig Smith]

Shane, that's basically true. What can be an issue sometimes is that wherever the motor is when it fires up is where it will fire injector A, whatever cylinder that's wired to. Could be different every time, and sometimes injector timing variations relative to the intake valve event can cause inconsistency. It's usually not enough to notice from what I have seen.

 

[NoSlix]

Gotcha! That makes sense.

 

[540Malibu]

thanks for the input, i guess ill just knock off the little tabs then, or i could just get out and put the motor in the same pos. with a breaker bar every time i start it , ill consider the bank to bank, but i need this motor to idle without a hitch.

 

[Superskwrl]

540malibu, maybe you should contact quest racing in worcester, they've got experience with big motors and FAST

Are you gonna run this combo @ quick street @ NED?

 

[540Malibu]

i dont know if im gonna run any class races yet or not, but once its together ill be up at epping just about every other week running time trials or scaring hondas on street nights or something.