ok everyone i got to get some opinions.
i wanna race a 92 305 5speed tpi z28 all stock. and i got a 1983 Recaro Trans Am with a fresh 305 13k on the motor and a 210 to 213 degree cam, accel cap and rotor, accel super coil, moroso blue max wires bosche plat4 plugs,3 inch flowmaster exhaust, removed cat, a/c belt and a/c unit, smog pump belt removed, k and N and a 700 r4 with 3.23 in the rear. if anyone can also guess a 1/4 mile time for me that would be awesome too! thanxs to all the 3rd gen people out their! recaor xfire
p.s. my recaro is for sale and im gonna miss her when shes gone!!!

 

Tell me more about the Fresh 305 13k on the motor? Any cylinder head work or headers? What about the intake? The Crossfire intake doesn't work, no offensive. Switch to a Edelbrock Performer intake and 650 cfm carb. Good Luck!

 

its hard to switch from a computer controlled tbi to a carb or i would hella do it in a sec. no cylinder head work
9.6:1 compression
58cc heads i believe
fresh crank, cam, heads, etc.
brand new long block
my cfi intake works alright tho
u might be surprised!

 

I would have to go with the '92.

 

The CrapFire has got to go. Until it's gone, your not going to beat much of anything. Have you ever seen how tiny the ports are in the intake? It's 3/4 the size of the port in the head.

The 92 Z28 has you by 10 car lenghts+. Sorry.



------------------
89 IROC-Z 5.7L 2.77 GEARS
130,000 MILES
ALL FREE MODS
K&Ns FILTERS
FLOWMASTER MUFFLER
PERFORMANCE RESOURCE CHIP
AFPR & PORTED PLENUM
Best 1/4 E.T. 14.09 @ 97.2 MPH
Best 1/8 E.T. 9.09 @ 77.4 MPH
Best 60ft. 2.03

 

i was hopeing for more support than that but o well im gonna race him as soon as i see him and get a chance to do it.
come on guys a cross fire vette with 200 hp will run a 15.1 @95 mph. u gotta have some faith in the cross-fire right?
with my mods in utah i would hope to run a 15.0 flat but never got tha chance to time it.
recaro xfire

 

I wouldn't say crossfire is that bad... it isn't as powerful as tpi, but it's a unique setup... I would still have to go with the z28, but not by 10 lengths... maybe 2 if you both know how to drive.

You haven't really done much more than exhaust, taking the smog belt off and gutting the cat can get you about 10 Hp total with a high flow exhaust... might do more if you still had stock exhaust, but of course then you lose Hp because of the more restrictive design. I would say that you would do just as well with a high flow cat. Running the smog pump will result in a loss of about 4 Hp, so I would say put it back on. Put some headers on that puppy and you might stand a chance.


[This message has been edited by ChillPhatCat (edited September 30, 2001).]

 

i gotta say as well that you will lose, cfi just isnt any good, and you are racing one of the best 305 tpi's there are.

 

One other thing... I think part of it is sluggish throttle response, If you switched to 600-650 CFM carb, you would see a big improvement in response, you'd probably gain a few Hp and the car would be much friendlier to mods. Go with a performer intake and any carb you want, just get a vacuum advance distributer and a non computer carb and you can ditch most of the computer... it's not more complicated than removing the motor for a rebuild... Just pull the engine light out when you do it and it's all good. Of course theres a couple more things, so if you do it just get a good set of detailed instructions.

 

Isn't the cross fire vette a 350??? Anyway, if you really want to keep the cross fire, there are a few people who modify them with decent success. I think one is Texas Turbo. I believe I read an article in a auto mag where you send them the intake and throttle bodies, they modify them and send them back to you. Probably not cheap but you retain the cross fire.

 

jayszee thanxs for the info on the modding the tbis and intake!
to everyone else thanxs for the opinions!
recaro xfire

 

crossfire has potential...you just have to tap into it. I remember seeing a vette board and there was a post by an '84 vette crossfire and he was running mid 12s... who remembers the '69 Camaro Z28? remember the cross ram intake? factory claimed 50 horsepower increase. That car ran high 13s stock. What about the max wedge hemi chryslers with cross ram? those were fast drag cars. I say port the intake to the max and throw some bigger TBI units on it or maybe better yet, get the turbocity dual twin TBI setup. That would haul *** .

------------------
1989 IROC-Z Convertible
305 TBI / 5-speed
Few mods
No times yet

My Thirdgen homepage:
members.v3space.com/thirdgen/index.htm

 

iroc22 got's the plan!!!!
he's one of the few who knows the cfi's
full potential. i dont know if ill have the money to ever switch over to the turbo cities setup but i got plans to get my car hella faster. just takes time.

 

I thought you said you were selling the car?

------------------
I WOULD RATHER PUSH A CAMARO THAN DRIVE AN IMPORT

1983Z28 350w/ edelbrock performer RPM power package , dynomax shorty headers, 700R-4 with shift kit, 750cfm carb, edelbrock 3" exhaust system, 16" IROC rims and ASCD SS hood.

future mods:
completely done over suspension, black paint with flames,
T-56 almost ready to go in, TPI swap coming up

Wifes new car:

95Z28, AT, leather, T-tops bone stock for now.

future mods:
header to tailpipe replacement and a cold air intake. Then I am just going to leave it alone

 

For a cost effective way of getting rid of crossfire you may want to think about is quadrajet. Many people switch to an aftermarket carb/intake so they are around. RB83L69 has shown me some very good results he has had with the stock quadrajet system with better drivability and mileage than crossfire. As you stand I think you will loose. I have a stock 305tpi with AUTO and I run 15.0, so with the 5 speed expect to get spanked. Carb may be the way to go, or if you got the $$ slap on a tpi setup and port it out a little bit.
peace

 

I hate to do this to you guy but... The Vettes had a huge advantage over the 305s being that it was powered by a 350 & had much larger intake ports designed for the 350. Unfortunately the intake runners on 305s were very, very small -less than 3/4 the port size of the 350. Being that the port is so small you will notice that the mods you do to it won't make much difference.

One thing you could do is find a CFI intake that came on the Vettes. You won't have to pay much for them because of how undesireable the CFI is over the TPI. The swap should be good for 30+ HP with your current mods. Yup, that much of a difference. Sorry to be so negative about the CFI but -I once (once) had a CFI car. Never again.


------------------
89 IROC-Z 5.7L 2.77 GEARS
130,000 MILES
ALL FREE MODS
K&Ns FILTERS
FLOWMASTER MUFFLER
PERFORMANCE RESOURCE CHIP
AFPR & PORTED PLENUM
Best 1/4 E.T. 14.09 @ 97.2 MPH
Best 1/8 E.T. 9.09 @ 77.4 MPH
Best 60ft. 2.03

 

Man, have you ever had the intake off of a CFI 305 before? Read my previous post. You would be shocked at how small they really were.

10 car lengths is roughly a 1 second difference in the 1/4. The 92 305 TPI 5speed cars were good for 15.0s stock. All stock???I'm sure that guy has done a few simple mods he's not talking about. Surely good for a 14.9 or better. The 305CFI with the stock intake is at best a 16.0+ car. Yes, even with the mods you have done. That's why I said " by 10 car lengths." Sorry ChillPhatCat it will be by way more than 2 cars.

Not Negative - Realistic

-Dave

 

as soon as the first snowflake hits the ground im not gonan sell my car, im gonna put it in the garage to get beefed up!
im worried that if i take my manifold off
and port it out that im gonna screw it up majorly!the shorty stlye hooker headers i got are a bitch to get to and install!
hopefully someone can give me some fedback on how much it costs to port out a manifold!

 

It would be way cheaper to buy the bigger 350 intake than paying someone to port the 305 piece. Go to a salvage yard and see if they have a 305 & a 350 intake to compare the port sizes. You will definitely see what I'm talking about. The stock 305CFI motor only made 165 HP. The 350 had 35 more HP but with way more torque. I believe the 350s throttle body is larger than the 305s as well.

Good luck on beefing up the 305.

 

im thinking i might just have to do that!
the more i drive my car the more i dont wanna sell it! i think tommaro or the next day im gonan race the z28. everyone in my auto class is trying to set the race up between me and him. i hate it because everyone looks down on my car and looks up to his! hopefully ill make a statement. i also wanna time my car 0 to 60 to see how close i am to his specs.
thanxs white iroc!
recaro xfire

 

Doesn't the 83' CFI have 190 horsepower? I think the 350 might have had more torque and horsepower because its a 350. We all know that the 305 TPI makes less power than the 350 TPI.



------------------
1989 IROC-Z Convertible
305 TBI / 5-speed
Few mods
No times yet

My Thirdgen homepage:
members.v3space.com/thirdgen/index.htm

 

Both of us are wrong. The 165HP CFI305 was in the "82" Trans Am & Z28. These are the correct stats on his car.
83 Trans Am & Z28 CFI A4 LU5
V8 9.5:1 5.0 (305) 175HP @4200 250TQ @2800

... OK, so I was 10HP off.

 

Hey recaro xfire, Check this out.


Cross Fire Injection (the 350cid L83 and the 305cid LU5 options) and it's primitive TBI fed cross ram would last only three short years in the F-body, and only two (or three depending on if you count '83 or not) in the Corvette. Cross Fire Injection was a stop-gap measure for GM and Chevrolet, to move the corporate giant from carburetor to fuel injection as smoothly as possible. Cross Fire Injection, while having a place in F-body history, is not a good performance system. The manifold <font color="red">is inadequate, and has very small runner outlets which makes for strong barriers to high performance usage.</font> The entire design will just simply <font color="red">not flow enough to feed a healthy (hotrodded) engine,</font> and the manifold or runners can't be modified for high performance use without extensive (and expensive) welding and reshaping of the runner outlets. It's just not worth it to try to extensively modify the CFI unit. Cross Fire Injection is interesting as a restoration relic and has limited use as a high performance intake system, but only if you know what you are doing. The CFI motors respond in their own way almost as well as the TBI motors do to very basic mods. Heads, cam, exhaust, pulleys, and you'll wake up your CFI motor to the point where it's running like you've never seen it run before!

The Cross Fire Injection system, a early, primitive form of TBI, found on early 3rdGen cars and even the mighty Corvette, is not a viable high performance TBI based option (the original factory setup of CFI, that is). If you really want to modify a LU5 5.0 liter or a L83 5.7 liter engine, then check out WWW.TURBOCITY.COM. They have a new CFI unit which will flow enough to feed a 500 horsepower engine, and they will burn a chip just for you when you buy the system! CFI can be made to perform, but it's a difficult and frustrating system to work with, as it exists in factory form, and knowing your limitations before hand will greatly ease your problems and costs during your buildup of this particular motor.



[This message has been edited by whiteroc (edited October 03, 2001).]

 

Yeah its true the runners are small on the Crossfire intake but I always thought that the huge plenum where the air/fuel mixure goes made up for that...just like adding a spaced on a TBI or carb, it adds a larger resevoir of air/fuel for the cylinders to draw from. Is there some truth to this?

 

thanxs for the address to turbo city
they got a tight *** fuel injection system to upgrade my cfi, but we all know it costs an arm and a leg. o well i guess i can dream about it.
thanxs guys for all ur tips and suggestions!!!
recaro xfire

 

Think of it this way -The huge plenum is the size of a trash can and the port is the size of a dime. According to your logic this set up should make 5000HP.

Now both of us know this isnt so. The intake ports need to be at a large enough volume to feed the cylinders as well.