roachjuice

well went to the drags and ran a 15.7..... at 88 mph..... it seems like it bogs real bad in first but past 3000rpm it goes.....i have more mods than some guys that run mid 14's..... i think i should be running at least 14.5..... i have the knock sensor wire unpluged too.... what the hell is wrong!!!!!!!!! what should i do to make my car like the cam???? how should i launch it???? i have a tq converter lock up switch when should i turn it on???? what should my fuel pressure be at??? what should the timing be at??? should i gap my spark plugs wider than stock???? before the cam my car ran 14.9 consistantly... now i have lt headers magnaflow exhaust a bigger cam and a **** load more..... the only thing i have stock is the heads,stock plenum runners and base,injectors,and converter.... feedback would be helpful...any sugestions????

1320_Guy

iTrader: (3)

Sounds like your stall isent big enough.

3.8TransAM

Plug in the knock wire.

Your car needs to be tuned (ecm) properly now due to mods.

85 computers suck. I would look ito the 86-89 MAF or step up to a 90-92 SD setup for best results.

U need to make sure everythign is verified good, both mechanical and electrical.

After that visit the DIY PROM board here and get to work reading.

later
Jeremyu

roachjuice

i think my car should be an easy 14 second car.....

RednGold86Z

iTrader: (1)

How about you post what your current answers to your questions are. Like fuel pressure, timing, etc...

You probably just have to set the timing correctly, and don't use the lockup switch.

Rickj350RS

iTrader: (1)

I ran 13.6 with a smaller cam. Everything else seems to be the same with my old setup, but I had a 2500 RPM stall and some 24 lb/hr injectors. I found my car liked it the best when I would smash it instead of footbrake it. I dropped an tenth just from that.

roachjuice

fuel pressure is at 53psi and timing 8 degree advance....it's like when i hit third it hits a brick wall.... and off idle and smashing the gas it don't like it..... thats when it bogs.... but when i bring it to 1200 rpm and go it don't bog as bad... the track around here is dumb... they call saturday night the midnight drags and they don't run the lights until an hour before close.... my car felt strong when the lights werent on..... i beat a 86 vette tpi and my buddies v6 tiburon with a six speed.... also when the lights came on i wanted to race a fox body with an exhaust and 5 speed..... well took off fine and was whooping a$$ until i hit third... and it boged off the line....he ran a 14.5......and i ran a 15.7

84t/a5181

Correct me if I'm wrong but didn't '85 tpi use a map sensor? W/the cam/rocker setup U listed I'm kida supprized it would run at all w/stock prom. What's going on is the duration and the lobe sep angle are increased to create "cam overlap" i.e. the intake valve remains open after the piston has reached bdc and is travelling up the bore...same for exhaust. As rpm increases this arrangement gains volumetric efficiency and creates more hp, but your computer has only 2 inputs to tell it how much fuel to apply: throttle angle and manifold vacuum (absolute pressure). and at idle U have very little vaccum coutesy of your cam, whereas once U mash the gas U actually gain a little...backwards from what the computer expects to see. This is a major reason gm was so interested in the mass air system in the first place because they could use alot of diferent cam profiles and displacements and the computer would still work, even though mass air sensors are expensive and failure prone. I'd do a little checking w/a known good vacuum gauge at idle/2500rpm in neutral and use a long hose to drive the car and note vacuum at various driving loads, especially part-throttle to WOT transitions and during upshift events like your 2-3 bog. What Id bet U will see is that vacuum starts out low at idle then increases at part throttle and then drops like a rock at wot, while under load the sudden drop in rpm caused by the upshift causes a momentary rise in vacuum which the computer interperets as less load on the engine, and we know that the exact opposite is true. Increasing converter stall speed would help this situation by allowing the motor to continue to turn in it's "butter zone", and is a good idea for aggresively cammed engines in general, but I think U are going to have to check out some aftermarket performance computers, or switch to MAF to get a real smooth transition from idle to wot. luckily there's lots of choices out there for cars like yours.

Mkos1980

iTrader: (8)

Ehh, with MAF you should be fine on the stock tune for now to at least run better or at least the same. I ran the 350 LT4 cam and TF heads, SR combo with stock chip for the whole dam power tour and had no problems. I'm betting its mechanically something wrong.

roachjuice

its a maf car... i can put my fingers on the injectors and feel them tick... the one on the front driver side is awesome the next one nothing... and the rest faint.... so i'm thinking injectors.....i'm thinking 22 pound injectors.... would i be ok with a stock tune for now when i install the new injectors....

cgtms

If you change injectors or fuel pressure, you really should make the changes in the PROM. The car will run, but it will run rich and your BLM’s will always be taking fuel away. At WOT you will be rich and may loose some power.

To get the most benefit from your new cam, get into the PROM. To improve your launch times you may also need to move up to a 2400 stall.

1MeanZ

iTrader: (9)

Lets back way the heck up here, this post is a mess of unanswered questions and confusion. I'll answer the original questions in order they were asked, and then tell you why your car is bogging like it is because mine did the same thing once and I fixed it.

Plug in the knock sensor (that was already stated)
Your car should like the cam as it is
Launch off the brake at 1600-1800rpm
I had the converter switch and it doesnt do much but beat up your trans.
Fuel pressure should be at around 45-50 somewhere. I run mine at 47.
With stock iron head keep your base timing at 6-8 degrees advanced.
Stock plug gap is fine.

I unplugged my knock sensor once and it did the exact thing you described. I suggest you plug it back in and go get some new times. With the exhaust and cam along with stock converter, and stock heads, your car should go high 14s. Mine went 14.8. Your stock computer and chip will be fine for your combination.

roachjuice

thank you!!!! now what about injectors????

freestylzz

Unplug (don't remove them just unplug the electrical connectors) on each injector and check them with a multi-meter (car not running).

They should register between 12-16 ohms. Injectors severely under 12 ohms won't function properly. Have any bad injectors (or all) replaced. The 22's should be just right.

joe91cam

i run a 15.6 with a 305 tbi with just ignition headers and open element the tpi cars in topeka ks run around a 14.5 14.9 and mostly stock

roachjuice

now heres another ? can i cross the injector wires like ignition wires????

AT9305RS

TPI uses batch fire, so as long as you dont get the driver and passenger side wires mixed up you can plug them into any injector

although there isnt really a point in doing so unless your injector plug clip is broken. and the plug doesnt sit all the way down on the injector

1MeanZ

iTrader: (9)

19lb injectors will be just fine for all but the most wicked 305