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i would like to here of the success or some help with getting hp. out of 350 t.b.i. or does anyone know a website with good info. my 91 has accell module. msd ignition , edelbrock heads , cam , intake , and matching computer. 9.5 : 1 comp , headers , adjustable fuel regultor. i can't seem to make it dance but i know it has the potentional. any help appreciated, it seems to be boggy in the bottom end
Not an expert - but -
What cam are you running?
Thie graph below was produced with:
CAM SPEC'S FOR 270 HP ENGINE
Duration @ .050" Lift Lobe
Int. Exh. Int. Exh. Centerline
204 214 .423" .446" 110
8.3:1 heads
Bert
very similar cam. you are semi limited when running a computer controlled engine . the cam i use is performer tbi from edelbrock #3702 .... while typing this i was wondering if a bigger tbi will flow more considering the manifold is sort of like a 2bbl carb style? if i boost up the fuel pressure to 14-15 psi it hesitates at low end ( too rich ) but loves the high rpm . stock press is 9-11 psi
if i go to 12 psi it rips the tires at low end but suffers in the high.
i helped a buddie build one. we used the 4 barrel t.p.i. off a '90 some model van and piggybacked them together (i know this is not supposed to be done) comp cam for tpi 212 218 @ .050 .444 lift ported the stock heads 1 7/8 primary headers we ran 9.5-1 compression balanced the rotating assembly we also had the intake glass beaded. this all in a 86 2500 pickem up. 700R4 trannie which we redone with a trans pac and new servo's this thing will melt the tires off the rims ( we tried lol ) also has a 3500 rpm convertor. i don't know my chevies that well this was my buddies brainchild and just sits around collecting dust
Man I got a 93 with a TBI, I guess it will be great when I get all the bugs worked out of it. I'm still trying to get my computer right. Looking for a chip. But I tell you this will be the last computer controlled auto that I do. All the rest are going to be old school raw power!
It seems this subject is coming up more and more. I've about had it with the computer controlled 350's myself. I may be crazy (you kidn't have to agree) but it seems like the computer is trying to counter whatever mods that are made to this engines. I have a 77 FBM 350 with RV cam and other minor mods that I mated to the TBI heads and intake. I've been having a lot of trouble with the idle control increasing to 1200 rpm at idle for no apparent reason. It will do this out of the clear blue and even do it while sitting at a stop light. It's possessed!!!!!!
I wanted to use a 93 350 I have in the crate in my 30 Ford but with all the trouble I've experienced with TBI I'm about ready to buy an old 283 or 327. You can set the timing and leave it, adjust the carbs and leave it and not worry about a computer screwing it up as a result of some unseen minor electrical problem. This kind of stuff takes the fun out of rodding and can drive you nuts.
Overall, from my experience, I think you shouldn't try to make a hybrid motor. Either accept the TBI as is or use the old carbed motors and tune as you go.
What do ya think?
yes the computer will not like any mods you do to the engine unless you put the matching chip with it. the computer throws a fit at idle because the increased vacuum on the map sensor . your timing curve and fuel mixture are also modded by the proper chip. there are companies that do this. my original post for this thread was trying to get even more power because i have done this. it runs 100 % but just looking to break the 300 hp mark with tbi. maybe i am expecting too much since its basically a 2bbl