I have an 88 IROC that had a wasted 305 and a 700r4. It was a one owner car in otherwise good shape with t-tops, power accessories (windows, locks, hatch). I bought it for $2,500 to take as my first "project" car. I so far, have made the following mods to it:

383 stroker, balanced and blueprinted
Dart Sportsman heads
steel crank
Roller rockers
mild hydrolic cam
9.5:1 flat top pistons
TH 350 trans
installed 350 injectors in the TB

I have replaced the O2 sensor, the TPS, knock sensor, the wires, plugs, fuel relay and taken out the thermac plate just inside the mouth of the air intake for more air.

Everything else is stock. It has 2.73 gears which I know needs to be changed to... 3.42 or 3.73? That is my first question.

Second question: Am I better off keeping the computer and tbi or changing to a carburated fuel system. I was told that I will NEVER get as much out of the 383 with a throttle body as opposed to using a carb.

The car runs decently but I don't want it to run decently, I want it to kick *** . It does'nt accelerate much better than my 92 305e RS and it will hesitate on acceleration sometimes, not always. Hesitation happens intermittently while accelerating from 0 to 3000 rpm. I don't understand why it just hesitates SOMETIMES. All info is appreciated!

 

Are you using stock t.b.i. unit? If so you can buy 454 t.b.i. unit from gm or holley makes one for t.b.i. for $300. Do you have headers? How about open element? Whats your fuel pressure? It sounds like your 383 is starving for gas and air. I was always told get air in and get it out fast! There's some knowledgeable people out here to help ya. You got decent set-up that should be putting up better numbers and performance....good luck

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88 camaro rs convetible 92 rims / flowmaster/ hypertech chip/ 3.73 gears/tbi spacer/open elemnt/hollowed cat/shift kit corvette servo/k&n filters/holley tbi unit/NITRO FOGGER /VORTECH HEADS WITH GM INTAKE/future mods 350 with 400 crank/sub frame connectors ....................favorite quote " I WILL SMOKE YOU BECAUSE YOU HAVE 305" SAME GUY LATER SAYS "ARE YOU SURE THATS A 305 BECAUSE YOU JUST SMOKED ME" *************************Check out www.camaroheaven.com for hard to find parts location new hamshire

 

Yes, it is a stock TB (w 350 injectors). I don't know the fuel pressure reading but I opened the fuel meter all the way. It doesn't have open element or headers. I plan on getting those when I have more $$$. Where would the best place be to get a 454 TB? After these mods, do you think I wili still need to get a custom chip burned? I talked to Street and Performance and they acted kind of leery about having a throttle body on a 383.

 

of course they acted leary, they dont know how to tune a tbi on that size engine. nobody does because anybody that has is not here at thirdgen. find them.

The 454 tbi with a new fuel pump(better w/ higher psi and gallons per hour) with an external regulator and a blocked off stock regulator will help you out emensly, also get some 454 injectors and an open element air cleaner.

in the LONG RUN you will like having a tbi much better than a carb, because of drivability. do you want it to kickass on the weekends at 10mpg, or everyday at 16mpg

do a search for shane buss 's posts, probably one of his latest talks about how he wished he would have kept his tbi system for his beefed 355.

last but not least, you will most likely have to get into the custom chip area.

all of this is going to cost more than a new carb i guess, so if you were to swap to carb i would understand. But. i really think its all about the long run, me personally, i want a kickass machine, that runs good all the time, starts right up in winter without having to pump the gas 50 times and that will get pretty good milage.

Also, just think of the respect you could have, and get, if you stayed tbi. Hell, i bet you could get a magizine spot

Hope that helps, really, it just sounds like youve got a bottleneck happening right now. little tbi with little injectors and litte air comin in. cure, bigger tbi,open el, and bigger injectors(w/larger pump maybe!).

let us know.

 

Listen let me refer you to a guy who knows what t.b.i. can do for you? His name is "Chip Mitchel" co-owner of New Englands biggest and best speed shop. There web-site www.indyautoparts.com Chip called me crazy 2 years ago for wanting to take out t.b.i. and going to carb. I'm stubborn but im glad I had listened. He knows what a t.b.i. can and cant do. there phone # is 978-535-8100 located 10 minutes north of boston & prices are competitive and they will also price match with mail order or go less....best of all they love chevy camaros! Remeber if you ask 10 people your same question you will have 10 different answers. Let us know how you make out! Peace brother........now go smoke a mustang for dinner!

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88 camaro rs convetible 92 rims / flowmaster/ hypertech chip/ 3.73 gears/tbi spacer/open elemnt/hollowed cat/shift kit corvette servo/k&n filters/holley tbi unit/NITRO FOGGER /VORTECH HEADS WITH GM INTAKE/future mods 350 with 400 crank/sub frame connectors ....................favorite quote " I WILL SMOKE YOU BECAUSE YOU HAVE 305" SAME GUY LATER SAYS "ARE YOU SURE THATS A 305 BECAUSE YOU JUST SMOKED ME" *************************Check out www.camaroheaven.com for hard to find parts location new hamshire

[This message has been edited by jeff88convertible (edited February 18, 2001).]

 

You guys are great and the solid info is great. Thirdgencamaros referred me to this site and I'm glad they did. I have got more useful info from here in 5 hours than I did in the past 2 months anywhere else. Thanks very much and I will definately keep posts up on my progress. I have noticed in a lot of cases that topics are started, given a wealth of info on and never really finished. I am sure alot of it has to do with the fact that it is a lengthy process getting it just right. But as I make changes I will post what the effect was. Thanks again!

 

thanks for the kinds words - from everybody

also, with the other posts, people who come here usually post again with their new news, we have all begun to know eachother at least a little, and know eachothers projects and progress. But usually, the posts are finished in a new one, a while later, instead of going back to the old one and adding to it.

 

383 using 305 exhaust manifolds....cough...AAHHHH!!! Warning Will Robinson, Danger danger . Also 305 intake is killing you. 350 injectors might be too small also, I'd go with even larger injectors from what you've said about the engine. Swap for a holley 670cfm, and get the adaptor plate, but it on a performer RPM intake with a drop base and you should see power ski rocket. I would get exhaust done as soon as possible. About the peeps saying a 383 TBI isn't really popular..ah..isn't it a very popular thing to build a 383 for trucks and use the larger TB? TBI on trucks for low end torque....383 stroke designed for torque not hp. I'm thinking TBI would be the best system for a street camaro. It does sound like your engine isn't getting enough fuel. Are you running stock fuel pump or mechanical? I'm thinking the cam is too radical for the intake and that is causing the problems. Wrong cfm combo's ALWAYS have problems. Keep us updated on problems and what else the car has.

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, Jon (91 RS too many mods to list), getting new engine in summer

 

I found some Hooker headers for $247. I can either get those or a 3.42 rearend first - they would cost about the same. Then a Holley 670cfm and fuel pump and then a custom chip. As usual, it's the $$$ I am waiting on but as things are added I'll post the effect on performance.

 

speedlvr..are you on the thirdgen mailing list? becuase there is a very similar topic to this on there...just wondering.

yeah you NEED exhaust like asap. and an intake and bigger throttle body will do you a ton of good. its all about the air flow...air=power, and that 383 needs a ot of it!

good luck and keep us posted.

-brian

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1991 Camaro RS - Ultra Blue Metallic, T-Tops
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GM 350 HO Crate Engine - Vortec Heads, Edelbrock Intake, Holley 670 CFM TB, Edelbrock Water Pump, March Pulleys, MSD 6AL, Blaster Coil, 8.5mm Super Conductors, Cap and Rotor, Rapidfires, Hypertech Fan Switch & Chip, SLP 1 3/4" Stainless Headers, 3" Cat Back, Flowmaster 40 Series
700R4 - 2,400 Stall Converter, Vette Servo, Shift Kit, B&M Super Cooler
GM 10 Bolt -coming soon Auburn Pro Series Differential, Richmond 3.73s
Brian's 1991 RS Central NY F-Body Association
Join the Third Generation F-Body TBI Web Ring
z28boy@twcny.rr.com IM name: Z28 Boy

 

that engine is choked

the stock intake manifold is crap
the stock throttle body is crap
the stock exhaust is crap

lose all of that, and start doing your own chips

 

I agree 100% with Pablo and will go further by saying that even the 454 TBI Unit will be too small for a "built" 383. I am speaking from experience on this 'cuz I have gone down this road already I dealt with Turbo City, Superchips, Arizona Speed, etc.

I wanted TBI on my setup and that's what I did. I went with a Holley Projection 4Di 900 CFM TBI with 85 lb/hr injectors. inline pump rated at 410 lb/hr @ 15 psi. plus a bunch of other mods. I don't know how deep you are in with your 383, or fast you want to go, but the beauty of Holley's 4Di system is that with a laptop you can dial in your maps at any time and save them. You can have fuel maps for racing, for economy etc. and upload them into the ECU at your heart's content. To date I have run a best of 12.492 at 105.25 on nuts with Nittos and a 3.73 rear end. Wait till I fine tune it some more and then I hit it with the spray.
remember this is ALL with a TBI system. Oh yeah I Drive it 60 miles (one way) to the track smiling the whole way.

Good luck.and check these sites out for more info.

www.forgedperformance.com

www.

 

No need to beat around the bush, Pablo. Just tell it like it is.

 

I don't plan on doing any racing now, but may in the future who knows? Right now my short term goal is to be able to go out on the street and be able to give anyone a run for their money. I went on the Holley site and looked at the setups for 383's and all I saw were non computerized stuff in the throttle bodies. How much did you spend on your TBI unit and pump?

 

frmula, welcome to the board, havent seen you before sounds like you have a nice car, 12.4 is just brutal

I think the 454 tbi is good to 350 hp but thats pushing the outer limits with it... this from all ive heard from people who've gone that route. For your 383 however, I do think it will suffice because you have a mild cam.
The important thing here is to start doing your own chips. Not too many people do TBI build ups. As such, not too many companies have done chips for tbi setups in person.. this compounds the problem of them guessing what your setup will want since they have no foundation for their guesses to begin with

 

Thanks pablo. I don't say much but this topic caught my attention.

Speed. Would you believe me if I told you I scored my 4Di setup on Ebay?? I bought the inline pump new. I also reworked the stock gas tank. I had two 1/2" bungs welded into the back of the tank. I have a 1/2" dedicated line for my N20 system, with a Holley "blue" pump. I jet my plate with "carb" jets since TBI operates at lower pressure than a Tuned port system. (I learned this the hard way on my 305 when I leaned out and set my air filter on fire). and set my erichment fuel to 12 PSI. I have not yet sprayed the 383. (My 305 ran flawless with the N20 setup and ran 14s all day long with a 125 hit of the sauce).

I re-used the factory 3/8" and 5/16" supply and return lines to feed the 383. The return goes stock location in the tank and the supply gets routed with some -6AN braided hose and inline pump to the other 1/2" bung. I prefer the inline pump over an intank pump simply for maintanance reasons. (I hate having to drop the exhaust and panhard bar to drop the tank to service/replace a pump.) I plan to dump the stock supply line and go with -8AN and 1/2" alum line because I believe the 383 is starving for fuel on the big end (which might explain the low MPH). On desktop dragster my set up should be good for 11s on motor with slicks.

 

I haven't gotten into the fuel pump/tank yet simply because I think it will suck! But I know I am going to have to. When I get an in line pump, do I just take out the in tank pump and toss it? Also, are there any sites where you can calculate horsepower? Dyno tests are expensive.

Pablo, I saw an article somewhere on making your own chips and the equipment needed for it. I can't remember where though. You know where I can look?

Thanks

 

Just throw out the intank pump and cut the wire that sends juice to the pump I believe it's the purple wire. Double check where the wires go before you cut because there are three wires and you still want your float to work (fuel level gauge) The third wire is ground leave it alone.

Dyno software is cheap. and pretty accurate. I had my motor dynoed before I installed it and the numbers are pretty close.

 

The 670cfm should be plenty with a street cam.

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, Jon (91 RS too many mods to list)
Dale Earnhart, you have done so much, you will be missed.

 

speedlvr, the article is right here on thirdgen look in the tech section.. theres an EXCELLENT article written by Tim Siford (aka TRAXION)


be sure to read all the links

as for the fuel pump, ive done that a few times. I ended up installing a 42gph at 38 psi unit which works flawlessly with my combo which i run at 19.5 psi, you might want to look into doing that if this isnt a racer, a sump with a hardcore external pump is probably what you want if you are running like FRMULA here


FRMULA, not to point out somethign you may allready be doing but, remember to read your plugs.. these FI systems can seriously decieve you in the fueling dept. i went months and months thinking i was lean because the car just simply ran out of breath on the big end.. i kept richening it up with the chip, and other methods, i ran like 89 mph at the track in a car that should have done 100
I was rich in a bad way.. after some dedicated plug reading things are about on target now. dont pay attention to the O2 sensor its garbage for WOT btw

 

Pablo, I think you are making the right call on this one. The car was running RICH and we adjusted the the fuel map to lean it out a bit on the street. Then we went to the track, that's when I ran my 12.492 at 105.25.
But I think it is still on the rich side because the exhuast really has a strong smell of gas. (I don't have a cat either). I might drop my fuel pressure a bit and play with the fuel map some more to see what happens. My Inline pump flows more than enough fuel at 15 PSI (410 LB/HR = approx. 68 GPH) to feed a 500+ HP motor. I should only need about 9-10 psi to feed the motor. I believe I have my pressure set at around 12-13 psi right now.

Also what is BEST way to read plugs? Right after a run should I shut down and coast to the end of the track. Let the engine and headers cool down a bit and check ALL of the plugs?

 

Heres how i do it frmula,

I have a deserted stretch of road near my house with a decent shoulder i drive out there with a few new sparkplugs, a leather handymans glove, and the sparkplug socket

with the GM computer, the wot fuel enrichment goes in like 400 rpm increments
so in my case i know where each increment is.. say i wanna know how im doing at the top end, i know there is a fuel increment at 5600
So ill get the car into 3rd gear and go WOT to 5600 rpm.. just as the tach hits 5600 i cut the ignition and push in the clutch.. put it in neutral for the auto
coast to the side of the road, and pull an easy to get to plug. The best way would be to read all of them but thats too damn hard to do with a thirdgen and really i havent found it neccessary.
I pull the #3 plug
reading plugs from regular pump gas takes some practice to even know what you are looking at but it can be done and is very helpful
The nose shouldnt have any dark coloring at all, in MY PARTICULAR combination, my car runs strongest with the FAINTEST beige haze on the porcelain nose.. its really almost invisible its so light.. its essentially just one step below any real easily discernable color at all on the plug nose. Pump gas burns CLEAN. I went the longest time reading my plugs using guides for old school gasoline and they were just totally off, my car was so rich it was rediculous using they old timers plug coloring guides

before you worry about color make sure your heat range is right, your side electrode shouldnt have any "bluing" (like what chrome headers do) and look at your center electrode, the edges of it shouldnt be getting rouded off, thats a sign of detonation. Also watch out for little specs that are salt and pepper looking on the nose, thats detonation those are little bits of the combustion chamber that broke off
you also might see some pinkish little color spots on the nose.. i occasionally see them, thats an additive to gasoline called manganese, it can cause misfires it sucks, so if you see it change fuel brands

so in my case, I ended up pulling alot of timing out, going to a colder plug, and leaning everything out a ton
just remember you dont want any real dark color on the nose at all it should be pretty much clean of any color. I like them to be just one step below any easily discernable color shows up at all but when inspected closely should have just a very faint (like almost invisible) beige on the nose
just be sure you arent knocking or overheating the plugs on top of everything

[This message has been edited by Pablo (edited February 20, 2001).]

 

I cant remember his Username, but his real name is Steve, he has done some cool mods to his car. He is installing a 383, he could probably give you some advice. Check out his webpage.

http://members.nbci.com/scauffiel/

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Godti
'89 Trans Am (Red)
305 TBI 5spd

 

Thank you God. I appreciate it!

 

I think he is putting on a crossfire system.

 

IM IN THE SAME BOAT I HAVE A 89 CONVERTABLE RS IT HAD A 305 WITH A 700R4 I HAD THE TRANNY SWAPED FOR A B&M 700R4 STAGE TWO AND HAD A LOCAL SHOP DROP IN A PREFORMANCE CHEVY 383 THE CAR IS TBI . I ORDERED A BRED 454 TBI FROM E BAY (MISTAKE) IT CAME IT HAD BURS AND SAND IN ALL THE CREVESES AND HOLES. IT RAN LIKE **** IT DROPED SOOOO MUCH FUEL I T ONLY RAN WITH 1 INJECTOR HOOKED UP. IM NOW RUNNING THE CAR EVERYDAY(70 MILES TO AND FROM WORK)WITH THE 305 TBI ON A 383 IT RUNNS OK BUT I KNOW THE MOTOR IS GOOD FOR OVER 400 HP& TQ BUT IM NOT GETTING IT . IT LAGS LIKE YOUR DOES BUT IT ALSO SEEMS LIKE IT VAPOR LOCKSEVERY ONCE IN A WHILE. I WOULD LIKE TO HERE HOW YOUR CAR ISSUES WORK OUT. AND IF ANY ONE COULD RECOMEND WHAT TO ADD TO MY CAR TO MAKE IT GOOOOOOO. DONT GET ME WRONG ON A GOOD DAY IT WILL LAY THE SMACK DOWN BUT IT IS SPRATIC AT BEST.

 

My 92 camaro has a 383 with the stock tbi unit and 350 fuel injectors. I also installed 3.73 gears as a daily driver and wouldnt turn back. The acceleration is great though it tops out at around 125 or 130 I believe speeds which i'll never have to travel at. I think a properly tuned tbi makes good power with the advantages of being fuel injected like slightly better gas milleage and overall easier starts. If i didn't have emissions id consider switching to carb but i really like how easily the car starts up in cold weather compared to carberated engines. Just my opinion.
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Also Im guessing you already burned another chip for the new engine if not thats probley why your having some problems with hesitation and what not. Also i highly recomend headers and opening up your stock exhaust.