All i've done to my car is a 14x3 open element and a hooker catback. I'm just wondering if its safe for me to say that i have 180 HP (at the flywheel) or not. I mean i get kinda embarassed because people think my car is really fast, and then i tell them its only got 170 HP and they bug out. 180 does definately sound better though

 

whats an rs with exhaust run in the quarter? and to answer your question, i got hooker headers and borla wide ope 3inch cat back and gained 30 horse, so i would have to say at the flywheel you have more than 180 but thats not fact just opinion

 

30hp with shorty headers , no cats and borla exhaust?

 

I wouldn't doubt it. I've seen estimates and quotes of 30-40 HP gains with a full exhaust. Now from what i understand he might not see the full gains until he does tuning, but full exhausts on our cars do ALOT.

As for me, i estimated that the catback might have given me 5 HP, same with the open element. So i'm hoping to be at a pathetic 180 HP.

 

I think 180 is the MAX. No more. I'm not sure though.

 

If they're non-car people just tell em it's got 300 hp and they'll never know the difference, it'll feel like 300 hp to some one who drives a camry. I had some of my friends from high school conviced that I had "Nawwws" because of the way the power would come on when the secondaries opened up on the quadrajet I was runnng.

I also had people thinking I was doing 1/2 mile burnouts leaving school...when saddly it was just oil smoke

 

I like that, lol

I would think that an open element and a good catback might give you 10 HP. Or you can throw on some spinning rims, a VTEC badge, and a honda noise box muffler...that will give you at least 50 HP. Don't forget the thumping boom boxes in the back.

 

no way in hell anyone will get 30-40 hp with full exhaust on a 305 tbi, its not gonna happen. to make an illustration, i had a 4.6 mustang gt with dual exhaust, after i put in flowmaster's, ive got a 2 h.p. gain. then i threw on some shorty headers and got a 6 h.p., then i replaced the stock h-pipe with its 6 cats with a bbk h-pipe with dual high flow cats and got a 12 h.p , along with a k.n air filter , 6 hp were talking about 26 h.p. max throughout the rpm's, now this is the much more advance modular v-8 4.6, which is known to be corked down in h.p. from the factory.

 

He's not driving a Mustang so that doesn't really apply.


I too have seen some LO3s that respond very well to a full exhaust conversion. I think in the neighborhood of 30hp. I've done some exhaust and intake work and I figure it's worth about 10hp. And you're right, people are surprised when they hear 170.

 

Probelm is the mustang has duels from the factory, the Camaro dont so it aint even in the same ballpark.

 

sorry guys i seem to be the only one in here talking that has the tpi 350 and dyno results claim 30hp, so think what you want and have a nice day. if your gonna hook up your camaro start with a 350. thanks bye

 

If your going to buy a life let me know where you get it from. I like my 305 and there are some Tbi guys that will beat your 350 on here im sure. Why come and be a ****, and if your not then it sounds like it at least.

 

That's idiotic.


Dude dyno your car and get REAL numbers. Ya know, real RWHP numbers...

Why is it that 99% of LS1 guys get RWHP numbers and 99% of yall speculate about your FWHP??? Take it to a dyno...

 

I could care less, who the hell is going to waste a trillion dollars to dyno a LO3 with two mods? From what I understand people have done exhaust and dyno'd them and got these good results. How can you argue when you have 8 cylinders breathing through like 1 cm crimped pipe?

 

a mack... your car and mine are about identitical. With a good tune and the mods you have you can say 180 HP. It's in the ballpark.

Where you squish your import-lovin' class mates is in the low-to-medium range torque section with around 260 being made. Plus, you'll get around 25 MPG on the road. What's not to like?

Gawd love a truck motor.

 

im just using an illustration, theres no chance in hell you'll squeeze 30-40 h.p.
out of an lo3 with full exhaust, and for the price of headers, catback you might as well buy a bunk 350 from the junk yard, buy a rebuild kit and have a shop built it up for a few hundred more...

 

But won't you still need to buy the headers and exhaust?

 

Ummm yeah so how much power will that 350 make with the smallest V8 exhaust gm ever put on a performance car and a cat thats going on 20 years? The exhaust is where you start with any build up.

 

But they're two completely different engines, with two completely different exhausts. There was a post on here not too long ago about a guy that got his 305 to about 320hp. The first thing he did was the exhaust and the dyno numbers jumped up by about 30hp.


*edit: here it is.

http://www.mainstreamtopics.com/foru...showtopic=3266

 

well i'll be damned... im in a state of disbelief. but the author doesnt mention anything about tuning and that is an 1982 lg4 motor , im still skeptical...

 

I'll agree that a full 3" exaust will add close to 30 hp, with tuning. The stock exaust is crap, complete crap. It's 2 1/2" piping that for the most part is much smaller from where the pipe was crimped to make the bends, and the exaust manifolds seem to be almost as restrictive as the piping. When I switched to headers and 3" exaust there was a night and day differance.

 

I made 300 RWHP with open cutouts from a 305, well 312, TBI. Through the mufflers it made 278 RWHP on its best pull. It pulled a 5,300 lbs FULLSIZE VAN to 9.89 @ 69.08 with a 2.18 second 60' through the exhaust. It went even faster through the cut-outs, but I don't have that timeslip in front of me to quote.

I have tuned a Cadillac L03 in a Chevy Truck with a full exhaust including JBA shorty headers. It made 181 RWHP @ 4,200 and 268 ft/lbs @ 2,200 on a Mustang dyno.

It is VERY possible to get 180 RWHP out of a L03 with a full exhaust and some tuning.

 

I think the stock is 2 1/4...since my Dynomax cat-bak is 2 1/2" pipe, which is an upgrade from stock...but I'm sure a mandrel bend 2 1/2 inch catback is much better than the stock setup.

 

Stock exhaust on a L03 car is 2 1/4 from the Y-pipe back. I think it is either 1 7/8 or 2" before the Y-pipe. I don't even think you got the monolith style cat either?

Truck/Van L03s came with 2 1/4 exit manifolds and pipes before the Y then up to 3" then into dual 2 1/4" or single 3" exhaust after the muffler, from GM! And were rated at 175 @ 4,400 and 265 @ 2,800. That is with a hydraulic flat tappet cam as well as 9.0:1 compression vs. 9.3:1. Trucks also run a mechanical belt driven engine fan and pellet style catalytic converters. Not to mention that the Computer tune was even worse in trucks than F-bodies. Lots of fuel and not much timing was the name of the game.

PE air/fuel ratios of 11:1 and 22-25* of timing are not what I call power makers!

No wonder installing a small cam and bumping the timing up to 6* advance woke my old L05 up so well.

Here is the chart for the G-Series line.

The 1993 ratings for the 305 are wrong!!! Those are the ratings of the 4.3 HO TBI. I have never seen a TBI 305 rated below 250 ft/lbs.



BTW, the exhaust manifolds on the L03 trucks are also substantially better than the ones on a L03 car.



PS, the plug wires running to the front of the engine was a Joke from a Ford loyal friend.
He was like where the heck is the distributor?

Here is the final lineup Truck/Van vs. F-Body

Truck/Van
A.)Better exhaust system
B.)Better exhaust manifold
C.)Weaker PROM calibration (for extended periods of loaded WOT)
D.)Lower RPM shift points (3,800-4,200)
E.)Mechanical belt driven fan
F.)Less restrictive air cleaner (less stringent on noise standards)

F-Body
A.)Hydraulic roller camshaft
B.) Electric engine cooling fan
C.)Better PROM calibration (light passenger car)
D.)Higher RPM shift points (4,500+)
E.)Higher compression ratio

Combine the best of both and you could easily make 180+ RWHP.

 

Nice reply, Fast355.

Thanks!

 

still after thinking about, that article leaves more questions than awnsers, it stated 270 hp was made with full dual exhaust, edlebrock intake and camshaft, how many here have that set up on their 3rd genners and barely touch 220 hp?

 

The article in question is Car Craft's 325 HP 305 build-up. It was based on a 1982 LG4 305 complete at 8.6:1 compression. The cam was a hot comp xtreme energy 262 (alot more than most put in TBI engines), it had a performer RPM intake and later a Victor Jr. The performer RPM spreadbore with a Q-Jet made the same HP as the Victor Jr. with a 750 holley, when it had the stock cam. Why they chose to retain the Victor Jr. after the cam swap is crazy IMO. The performer RPM and Q-Jet was likely to have performed even better than the 270 FWHP they produced. The 416 heads flow a little better on the intake side than the 187s do. But the 187s have better exhaust flow and fast burn. I think one should run a single pattern cam on a TBI engine for this reason. The intake/exhaust flow ratio is closer togather on the swirl ports, negating the need for a dual pattern cam.

The reason that most can barely push 220 FWHP after TBI engine mods is FUELING. They NEED chip tuning BADLY, just don't do it and wonder why it runs like crap.

 

Quick question: about how much hp can I get from a Z28 or GTA exhuast? I'd like to open up my car a little bit, but I can't afford a full aftermarket exhuast. So would it be worth it to pull a 3" Z28 exhaust from the junkyard?