LoudmouthSS

iTrader: (6)

Decided to finally dive into the motor a bit...picked up some parts at good prices just to see what i can get out of her.

I got a set of 081's im going to clean up a bit, lt1 camshaft and probably some roller rockers for good measure. I did order a walbro 190 to make sure i had plenty of pump. So all in all the car will have free tbi mods, full exhaust, 081 heads, lt1 camshaft, full roller rockers. Now as far as injector selection and fuel pressure goes...what do you guys suggest as a good starting point? I figure 350 injectors would be fine...possibly the cop car ones if need be but what do you guys think?

86z/92rs

305 tbi should still work with that set up, just bump the fuel pressure up. Which route are you going with the fuel regulator? The TBI or afpr? If and when you do start on the ultimate tbi, take pictures and notes and post it on TGO for other to see/follow.

galvarado

I had 68lb.(cop car) injectors on a Vortec 350 with a ZZ4 cam and the engine didn't like it. It ran much better with the 55lb. injectors at around 20psi. I agree with 86z/92rs on using the stock TB and injectors and just increase the fuel pressure. Plus the 68lb. injectors are expensive(I believe I paid almost $300 for mine).

robertfrank

iTrader: (27)

Add some tuning stuff,some gears and a S10 converter to the mix and it will move quite nicely.

LoudmouthSS

iTrader: (6)

o yea yea i do all my own tuning, i have the car running great right now. and yea i am using the stock tbi for this build...i heard it will support up to 300hp correct? And the free tbi mods are done to it along with an injector spacer as well. I also have an afpr on there already. Now here is something i did notice, i am pretty sure it was just the fact that the fuel pump couldnt push enough fuel but.. Anyway i had my stock pump (its been replaced a bunch of times by the previous owner, so its a "new" stock replacement) pushing near 20 psi at idle, of coarse as soon as i revved it it would drop to 13...it couldnt hold 20 (i expected this). I didnt realize it was at 20 psi when i first starting tuning and when i started tuning i couldnt get idle to richen..i kept adding fuel and it would keep going leaner and leaner (blm reading) So i finally checked the fuel pressure and realized that at 18-20 psi the spray pattern was very odd...it fanned out alot, not alot of wall wetting of the tbi. Now is this bc the stock pump couldnt support 20psi? or am i going to have to get new injectors? Once i discovered this i pull the fuel pressure back to 13, revved it and it held 13 and the spray pattern looked much better, and then all my tuning nightmares were gone.

Robert frank, i notice you have quite a bit of stuff done to your tbi..any numbers or times from that thing yet?

LoudmouthSS

iTrader: (6)

On another note, i recieved my heads today...opened the box and immediately saw perimeter bolts for the valve covers and thought "****". Well i looked at the casting and noticed they are 601 heads...which is fine haha. These are a pretty sweet set of head from what ive read but i also see they are 53cc heads...what compression would i be looking at setting these guys on top of a L03?

thomas1976

I trew my injector pod spacer in the garbage after 1 week, altought it wasent adding much of weight to the car.


Surprising the stock pump made 20psi.
I had an xtremefi AFP sring that couldent hold the FP steady over 18psi, right now Im running 21psi with top down solutions AFP spring.


TPI fuel pump and 21psi AFPR with stock 55lbs injectors is sprayng nicely, tuning the higer FP in was the key in my case.

ownor

iTrader: (5)

why discard the injector spacer?

btw which way of displaying the FP are you using thomas1976?

thomas1976

No difference with or without the injector pod spacer, so put the stock gasket back on.

I used a Actron FP gauge and in line adaptor next to the alternator. Fixed the gauge to the wiper wile driving.

U can check my upgrades in my profile.