Okay i have a 14inch edelbrock open element filter and ultimate tbi mods and headers.And i got beat by a 16.4 crx with intake the crx launched of course stick and spun the wheels for 1 second so i flored it and spun the WHEEL RIGHT WHEEL no posi with 2.73's and spun it for about 3-4 seconds and we raced for about 1/4 mile and he was about4-5 feet in front of me.So do you think i lost just because of the poor really poor traction.Or because its tb injection.


Also i still have on the stock exhaust tail pipe from the factory and a flowmaster muffler. And my tranny slips when it goes in to second and third but when i floor it it slips a littly.

Also which would be better 3.42's with a posi or finish the exhaust system also since im spinning the tires bad what do you think i would be running with my current setup then what do you think i would be running with the gears and posi and full 3 inch exhaust.! more thin i think i might have a 350 tbi i might buy what should i run with that stock with ou the headers.

 

check my sig for my mods. very similar to you but no headers yet.

previous best of 16,69. put a 3.42 posi in and ran a best of 15.94 last night. no other changes.

go with the 3.42. it's more than enough gear for you. a lot of guys like 3,73s, but as soon as you start making serious power, you'll run into wheelspin problems. build for torque and let that torque pull the smaller gear.

 

You're losing all of your power in your gears... I ran a 15.6 with my mods, however my engine is gasping for more air.

We're both losing all of our power in our gears. My friend with a carbed 305 (former TBI) with 2.73's and full 3" exhaust (SLP headers back) ran a 15.7 that same night. I originally ran a 16.8 that night, but I shifted up manually on the 15.6 run. I held it to 5000rpm and was in 2nd gear the whole way down the track damn 2.73s...

 

dont blame it on TBI, you probably need suspension work and more mods. THere is nothing wrong with TBI, just the engines they are bolted to.

 

Yea those times sound right. Gears, exhaust and suspension work will help.

 

I don't know about your setup because I ran about that time and I have the same setup as you except I don't have headers and mine's a convertible (more weight). So I don't know. Plus I didn't have the hood then and I had my system in the trunk too.

 

No offense directed towards you about my following comments, I do not want to start a flame war but I find your comment outrageous.

So let me get this straight, you're saying that its my GMPP 350 H.O. crate motor's problem that I'm running a 15.6 and it only has 2000 miles on a brand new motor? It is the TBI's fault, along with the inexperienced driver, me. I bet even the best driver could pull maybe a 15.2 with my setup. I gurantee that if I bolted on Tuned Port on my engine, I'd be in the high 13's, atleast low low 14's. I'm sorry, but the SB TBI will not supply 330hp/380tq, I don't care how ported it is...Because my TBI unit is ported to hell.

 

Fredless,

i'm not going to start a flame war either.

but even with the factory TB, you CAN produce more power than mid 15's. the problem on your car is not with the TBI. have you done your own computer tuning? if so what does your datalogs like?

 

No I have not. You have me on the "proper" tuning deal. Try to challenge the statement saying a SB TBI can make 330hp/380tq.

I know my car is not tuned and I have a generic 350 TBI chip and plus me being an inexperienced driver has a lot do with my mid 15 run. Even then, you CAN NOT convince me that a SB TBI will FLOW enough CFM to get my car into the mid 14's.

Try and make Peyton Manning play a great game while allowing him breathe through a damn straw and then say its Peyton's problem because he is performing poorly... He CAN NOT breathe to his full potential.

I'm going to say it, but I hate TBI but that doesn't mean I'm going to give up on it. I have a 454 TBI sitting in my garage waiting to be installed as soon as I get the linkage problem fixed and my IAC pigtail in from gm parts direct.

Show me real dyno sheets (not a freewheel one, one that is harder to turn like the street) of a SB TBI making 330+ hp.

 

a couple of points.

i think you're both right, partially.

it's not tbi's fault, it's the tbi unit you have on your car. while mpfi is definitely more desirable, you should certainly be able to support the hp/cubic inches you're running with a tbi

i also agree that a stock tbi PROBABLY won't flow enough air for the hp/cubic inch combo you have. but maybe not. it could also be the intake. in dyno tests done by traco engineering, an edelbrock performer carb intake with an adapter made a lot more hp/torque than the edelbrock performer tbi. the 305 they were working on made 300 hp at the flywheel, and they used a box stock tbi unit (no grinding at all) with 350 injectors and a custom chip.

now, with 45 more cubic inches and 30 more hp, you probably need a bigger tbi, but i'm running 15.90s with a stock 305 (except for ultimate tbi mods, which i don't think are worth much). your car should be faster with the current combination, as long as it's tuned properly.

rather than going to a 454 tbi and having to figure out the linkages, connectors, etc, you can get a stock tbi unit bored out to 2" from this guy in texas for less than you'll pay for a 454 tbi. i'll have to find the link to his page. sell your 454 tbi unit and do his instead.

also, it won't do much good to go to a 2" throttle body if you don't have an intake to match.

 

Back to the original post, you need to bring your car to the track and get some real times and then we can go from there. This street racing stuff is never accurate.

I dont think TBI is a bad system but i do agree that it needs alot of tuning in order to run correctly, but so do most Speed Density systems. Im close to running mid 14s on my stock L03 (stock heads, cam, intake, and tbi) with just a bunch of bolt ons. I just need to install my probuilt tranny and ACT 2400 stall TC and i think ill be there.

 

about boring out the TBI.....if you dont feel comfortable boring the Edelbrock TBI intake out to 2", you could try going to 48mm. There is a guy (not sure if it is the same guy mentioned above) that will bore TBIs out to 48mm. The intake should already be 45mm so it would only have to go out 3 more. 48mm TBI with Ultimate TBI mods and injector spacer should flow pretty well compared to stock. Also what are u running 55 or 65# injectors.

 

here's the link to the guy who does the 48mm tbis. http://users3.ev1.net/~thor10/tbodytest.htm

i believe turbo city also does them.
www.turbocity.com

i think you're right about the tbi performer intake not being able to be bored to 2", but again, i strongly recommend a carb intake with an adapter over the performer tbi.

 

just looked at your sig. high 14s out of that combination is awesome. congratulations!

what you've done just goes to show what you can do with patience and determination. tuning is critical on a tbi car!

 

i just got corrected by the guy at turbo city, who says the stock tbi is 48mm (1 11/16"). they bore it out to 1 13/16"

 

stock 305-350 TBI: 1 11/16" or 42.86mm

turbo city TBI: 1 13/16 or 46.04mm

48mm TBI: 1.89" (alittle more than 1 7/8)

Holley and 454 TBI: 2" or 50.8mm

 

fredless,

a couple of things stick out on your combination:

700-R4 4 Speed Automatic, Corvette Servo, 2100 RPM Stall converter
Mods:GMPP 350H.O. crate motor,complete MSD ignition(wires,6A box,coil),Flowmaster 80, Flowtech headers,2.5 exhaust(headers back),14x2 open air,170*stat,No cat (staight pipe). Ultimate TBI with GM VAFPR and 305 injectors. Yes it gets enough fuel.

flowtech headers. are those the 1 1/2" primary? if they are, they're too small for your car. you need at least 1 5/8" primaries, preferrably 1 3/4"

no cat. without chip tuning, i think you could be hurting yourself. i know several people who took their cats off and lost power.

305 injectors. wayyyyy too small at stock fuel pressure. i guess you're using the vafpr to jack the fuel pressure up. where are you running it?

 

I just wanted to raise tbfirebird's selfasteam..

I ran a 16.4 @ 80.6mph

with (see below) & :

a leaky injector
9psi of fuel presure (had gauge, no afpr. Do now. big improvement)
burnt coil to distributor wire (don't know the name)
old spark wires (i measured 3 ohms from them when i changed. should be around 14omhs)
old plugs (10k ml on them)
dusty k&n (cleaned it when i got home, got a small improvement)
sliping trainy (changed fluids after the trip. very little and very bad fluid. improvent here also)
left rear bearing bad. welded its seft to the rear. PITA to change
right rear bearing just about to go now
no thermostat ( it got jammed just before the trip.. i just pulled it out, no other choise)

The reason i ran with the car was that we had our first annual f-body finland meet.. it cost 20€ to run the day at the track (driver + 2 mecanics.) if i'd went and just watched it would have been 7€ per person and there were 3 of us
<-- i say to the whole pricing

anyhow... i wish that made you're day.. you're not the only slow one..

 

Correct me if I'm wrong, but dpesn't JPrevost run 13's with the exact same engine and TBI? Obviously you have other problems besides the tbi to only be running 15's with that engine. I ran a 16.3 BONE STOCK!

 

I think Jprevost has the Holley 670CFM TBI. I'm not knocking tbi, just the STOCK tbi. I hope to get enough air with the 454 TBI I have. I do not want to bore my TBI any more, it still will not satisfy me knowing I'm not maxed out.

Z28 Boy runs 13's with his TBI I believe and he has the 670cfm with BBC Injectors.

I don't know what my FP is, but thats WHY I bought the VAFPR.

My 65pph cop injectors were WAY to rich, I don't care if you say I'm wrong, I know from a weeks long suffering of driving with them and I lost tons of power...And that was running the STOCK FPR, not modded in anyway. When I get my 454 fitted and when that stupid pigtail gets here I'll install my 65pph injectors.

How is not having a cat hurting me? I have a tiny *** 2.5" y-pipe and I-pipe? My headers are small and restrictive I know, hence why I wanted it free-flowing as possible and the car ran like **** with the dynomax high flow I had on there, ran much better without the cat.

I do want a high flow cat 3" in and out when I can afford to have a 3" i-pipe installed because I HATE the lawn mower-ish smell my car emits.

 

Fredless, you have some big problems. I think Prevost ran that 13.8 at 102mph with the same engine an RPM manifold, Holley TBI and a dying fuel pump with limited tuning.

You should be doing much better than mid 15's with your combo. I say if you're not into the chip tuning and everything look at all that "Tom 400 CFI" has done (I think that's his exact name if not its close) look at what he did with NO chip tuning at all. You have to mechanically tune your combo first. Your 305 injectors are falling way short. Your fuel pump is probably not giving you nearly enough fuel if its stock and you probably need a decent amount of suspension work. Also, why buy a 2200? dollar crate engine and the cheapest smallest headers you can buy? You need a better exhaust system with those tiny primaries and collectors on the Flowtechs you're really hurting your times. The exhaust is only as strong as its weakest link.

 

Well i have a very bad slipping tranny i wish mine was stick shift not automatic.My plugs were on for about 20 thousand miles and my wires are about 40 miles old in 3years and my air cleaner and filter is also dirty and messed up also im also a 1 wheel wonder dam it sucks not having a posi.

 

Underneath the broken english and crappy spelling...If you spin for three or four second you're definately killing your times. Fix the tranny, get some LCA's and relocation brackets, swap gears, finish the exhaust off and you'll be golden.

Check my sig for the TBI Registry to see what cars with similar mods have done.

 

you guys suck doing the whole TBI arguing thing again.


my car weighed 3615lbs as it sat on the track that night.

i did a 16 flat... thats 16.000. almost 15s.


only "mods" were a open element, and the cat back wasnt connected.


its still a peg leg 2.73 rear vert with ****ty tires.


its either your launch causes you to spin, or you have somthing wrong with your car.

if you arnt nailing the launch, that time sounds about right.


you car isnt fast, so i say start "launching" the car when ever you can safely from a stop. dont worry if the minivan next to you keeps even, just work on not spinnin that one tire.


that alone should make you a 16 flat. if you want better, start tweakin on the car and find whats wrong.

 

ok guys heres what you ALL donot understand


my car fridany night ran a 15.21 on the motor with no help from NOS. When i ran that time i was racing a Civic SI.his time was a 16.45.however his sixty foot was 2.4 seconds.mine was 1.931 seconds.his 1/4 mile speed was 89 mine was 88.What im trying to get at is if a honda could figure a way to make power out the whole like they do at 8000rpms then they would be some pretty nasty little cars.So when i race him on the street he would probably kick my *** where as at the local dragstrip from a dead stop i would win every time come on guys do the math

 

I understand that, easy with the flame dude

 

tbfirebird, you say your air filter is dirty and "messed up" and plugs are 20k miles old and wires are 3 years old? If this is true then posi-traction is the least of your worries. You cannot expect to have good times with a car that is in poor tune. Too many people on here want to modify their car and throw on "performance" things before even tuning up the car. A FULL proper tuneup is necessary before doing any performance work in my eyes. These cars are old the newest being 11 years old, tune them up before going to the track or stating races you've lost while using a dirty air filter and old wires and plugs, of course you're going to run slow that's just common sense.

 

Money problems limited me BronYrAur. Flowtechs were the cheapest headers I could find with a y-pipe.

A friend of mine is running a ZZ4 long block with my old holley 300-66 Manifold and a holley 670cfm base with 55pph injectors. He is also running heddman hedders with 2.5" exhaust like mine and no cat. He also has the aussie 9 bolt rear end, 3.27 posi. Using stock TQ converter too!

GET this now, he is using the STOCK FUEL PUMP and and! STOCK 305 CHIP! The car has a surging idle like mine when it gets hot. His 91 RS will KILL mine, easily. He has also Spanked a new Hemi Dodge Ram easily (thats not saying too much) and he has beaten fox body 5.0 stangs.

I think me having non-lsd 2.73s, 305 injectors and "guessed" timing (I still am running a 305 balancer so we had to set the timing old school) is causing my car to run like crap.


No, i'm not into my own tuning thing because of cars like his. To me, chips are not miracle workers and I'm not ready to dump money into that area yet.

 

You think you have troubles now, wait till that 305 balancer take out your bottom end.

Steve

 

what? the 305 and 350 balancer are the same, or so many members on this site told me, just the timing mark was different on the 350 balancer?

take out my bottom end? I dont have a bottom end with my 2.73s lol!

 

well the 305 balancer and the 350 balancers are all the same except where the pointer is located at. his 'bottom end will do just fine. (talking rod and main bearings).

his 305 injectors are not hurting him in any way. i put my scanner on it. with the 'cop' injectors, the o2 wouldn't go below 890mV at any rpm. it had so much fuel it would blow lots o black smoke out. and nearly stalled out on me at an intersection. had it floored and wouldn't go. put the 305 injectors back in and fixed that problem.

better headers (flowtech are 1 1/2" primaries), 3" exhaust, getting rid of the 2.73 gears (i've swapped from 2.73 to 3.42 and picked up .5 from it alone), and better driving will get him closer to 13's.

 

yup. i think it's the 1 1/2" primary headers. the fact that the 305 injectors flow enough fuel prove it. he has a bigger engine now, which should flow air, therefore requiring more fuel. if the exhaust were more free flowing as well, the fuel requirements would greater yet. since they aren't, the only thing that makes sense is that the exhaust is choking the car down.

you're right on the gears, too. i went from 3.08 single traction to 3.42 posi and went from a best of 16.59 to a best of 15.95 with no other changes.

 

I know about the gears. Saving to get them installed. I have a 3.42 richmond R&P and Zexel-torsen diff. sitting in a box in my garage.

My car also does not downshift correctly sometimes...Much more tuning needed. Yes, my TV cable is adjusted correctly, even cut some of it off and using the Edelbrock Vortec throttle linkage bracket...It used to bog extremely bad before I did any of that.

 

Tune the car up. Get it running perfectly first before complaining its slow. no amount of performance mods, gears and miracles will substitute a healthy engine.

next your launch is terrible. 3-4 seconds of wheel spin is far worse than babying it off the line. All your torque is doing is spinning the right wheel instead of getting it to the ground.

Finally then get to the mods that get the car in balance with each other. That means gears that work with the power band of your engine. Too much gear and you can leave the powerband quickly before the finsh line. Too low and your never getting into the powerband. You want to finish the 1/4 mile at almost or at HP peak rpm of a 1:1 ratio on your tranny.

Its a constant thing tuning/testing, but you have to take the time and effort into this. Those of us running these cars on track spend a hell of a lot of time messing with it all. you don't get quick in 1 day unless your signing for debt into a brand new overpriced car.

 

what he said!


errrr .... except on the gear. that's how you calculate peak performance on a drag car. when you put enough gear in the car to finish the quarter mile at peak rpm, you're pretty much guaranteed gobs of wheelspin on street tires at the line.

in my opinion, a 3.42 gear is perfect for the street. you'll still be able to cruise comfortably at highway speeds and if your suspension is set up properly you can launch like a rocket with them.

as you add power to the engine, you simply need to remember that shorter gear and keep torque as tops on your priority list.

 

easier said than done on most of these cars. remeber we are talking about a 15 sec car, that is likely trapping at 85 mph or so. you are going to have to run some serious gear to get spinning to the 4300rpm HP peak.

with 3.42's 4300rpm is well over 100mph. great if you have an 11sec car. but not for a 15. and most people with 15sec cars don't want to run 4.56 rear gears. at least not if they drive their car to the track too.

 

It's not that hard for me. Although my latest dyno numbers say I'm not at my peak anymore crossing the line, I was before.

When I had a peak of 155 HP @ 4100 rpm I was pulling anywhere b/w 3950-4050 rpm depending on my run.

Result was a 89-91 mph trap speed.

Now that my peak is at 178 HP @ 4800 RPM I am crossing around 4300 rpm with about 92.5-93.5 mph trap speeds. From from the impossible I say even on these lowly 305 TBI cars of which mine is almost a complete stock engine. Check my post "New Dyno numbers..." to see the proof. It's not peak rpm at the line, but its not that far off considering I'm very much exhaust restricted by my stock cast TBI manifolds.

I have 3.23 gears that almost perfectly compliment the current powerband of my 305 TBI.