daveshapellSVT

OK, i have a 91 Formula that has a 4 bolt 350 in it. it's carbed and has a 750cfm edelbrock carb. It's not running terrible or anything i'm just wondering whats the most effective way to fine tune the carb for optimal performance. Obviously i can recheck the spark plugs and see what they do after each tweak, but that seams redundant and it's a pain in the ass. i'm thinking of getting a jetting kit, but there must be a better way to tune a carb other then trail and error and reading spark plugs.

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1994 Jeep Grand Cherokee Laredo 5.2 V8
MODS: kool vue cold air intake, dynomax catback, and KYB GR2 shocks

Morley

Nope, that's about the best way there is.

wrightz28

Yup, after a while you get the hang of it. Just remember that most adjustments are key when everything is stone cold, you get the best results.

daveshapellSVT

would a wide band help any at least i could figure out air to fuel ratios and get it closest to 14:7 as possible.

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1994 Jeep Grand Cherokee Laredo 5.2 V8
MODS: kool vue cold air intake, dynomax catback, and KYB GR2 shocks

Morley

A wide band would be used in addition to reading the plugs. BUT 14.7:1 is NOT the ideal air/fuel ratio, that is the "ideal ratio for using a cat. converter. At WOT you want to be more like 11:1 or 10:1. This is where FI really shines. During normal part throttle operation you can be runing the leaner 14.7:1 to keep emissions down and get better mileage, then through the programming you can fatten it up to 10:1 for WOT. Carbs are always a compromise, you either run rich (10:1) at WOT and 12:1 (or so) at part throttle. Or you run 14.7:1 at part throttle and dangerously lean at WOT. Even the computer controlled carbs couldn't match the abilities of FI for controling the air/fuel ratios.

daveshapellSVT

my next question is, are getting kits worth it? Will a jetting kit really allow me to tune shit out better or is it just worth it to try and mess with the stock jets in place. i'm fairly new to carbs. all my buddy's are fuel injected and using standalones.

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1994 Jeep Grand Cherokee Laredo 5.2 V8
MODS: kool vue cold air intake, dynomax catback, and KYB GR2 shocks

Morley

IF you are running rich or lean and the float level is correct and nothing is wrong with the needle/seat, then a jet kit is what you need to tune it. And if it is a Q-jet carb you also need a set of different size metering rods.

hotrod_chevyz

http://www.edelbrock.com/automotive_...ess_main.shtml

download the owners manual and go through it step by step. It explains it just fine EXCEPT when adjusting the A/F, step 9 says to "go leaner just enough to reduce the engine rpm by 20". Instead of doing that i use a vaccum gauge and reduce the engine vaccum by .5 inches a side (1 inch total for both sides)

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daveshapellSVT

Well i have an older buddy that is a mechanic and he's built muscle cars his whole life. he helped me tune it to where it is now, but he thinks i should get the jetting kit. really it drives decent i'm just wondering if theres some power to gain by tuning with a jetting kit. Edelbrock does give decent text on how to operate there toys, but i rather learn from someone in person. I'm just skeptical about my cars performance to me it seems like i should be about 3-4 tenths quicker in the quarter. i consistantly run 14.5's. my 60fts are 2.0 area on 235 street tires so i'm confident i'm driving it as good as it will go. i'm on stock timing too. Not to mention my 700r4 takes forever to change gears. i think it needs a rebuild.

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1994 Jeep Grand Cherokee Laredo 5.2 V8
MODS: kool vue cold air intake, dynomax catback, and KYB GR2 shocks

hotrod_chevyz

You should be able to bring it down to 14.2ish 1/4 mile. Im not sure of your exact configuration engine internal. With a good transmission and proper stall to match high 13's isnt out of the question with 355/700r4 in such a light car.

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daveshapellSVT

yea i think my tranny is the real bottleneck. it's got like 130k miles of abuse on it. feels like it slips. would a shift kit help shorten the time it takes to shift from gear to gear? next two things i wanna do are get a trans go shift kit and that jetting kit. both very cheap mods. in the future i'm thinking of a built t-5. be nice to shift again lol

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1994 Jeep Grand Cherokee Laredo 5.2 V8
MODS: kool vue cold air intake, dynomax catback, and KYB GR2 shocks

Morley

If it is slipping no shift kit is going to help, you need a complete rebuild.

hotrod_chevyz

What cam does it have?

With the hardware youve listed you should be more worried about it shifting early than late. Were talkin a stock valve body hooked to a motor with hardware capable of making power above the transmissions stock shift point. Things i suspect could be making you wait for a shift:

1: somethings off in the timing not allowing enough advance
2: the cam isnt enough to use the intake and carb to its fullest potential
3: the carb is still out of adjustment

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daveshapellSVT

yea i think it may be, but i'm not entirely sure. it feels like it takes too long to transfer gears. and i can't tell if it's just the fact that its a stock automatic, or if it really needs a rebuild. if i got a shift kit installed, and then later on had the tranny rebuilt would i need to repurchase another shift kit or can they still use that one? maybe i could get the shift kit, see if it helps, and save money. and i guess if it doesn't then just get it rebuilt. i have called before on a tranny rebuild and i was quoted 1200-1800 bucks. seems like way too much.

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1994 Jeep Grand Cherokee Laredo 5.2 V8
MODS: kool vue cold air intake, dynomax catback, and KYB GR2 shocks

Morley

If you hit the gas and the RPM's go up but the vehicle speed doesn't, or it increases very slowly, then the trans is slipping.
The stock 700R4's shifted pretty quickly from the factory so a slow shift may be either a misadjusted TV cable or a bad trans.