My bone stock 92 RS 305 TBI deserves some mods. What would you guys recommend?
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350 or 383 swap
Kevin91Z
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- Join DateJul 1999
- LocationOrange, SoCal
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- Car1990 Pontiac Trans Am
- Engine355 TPI siamesed runners
- TransmissionTremec T56
- Axle/Gears12-Bolt 3.73
- Likes:115
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This forum is for talking about Superchargers, Nitrous, and Turbochargers. Please post in the TBI forum, after you read the two tech articles about the Ultimate TBI mods.
Supreme Member
But but but, it says "Power Adder" I want to "Add Power." 
/sarcasm

/sarcasm
Im with you vwdave.lol
Anyways, I cant decide supercharger (less maintnance) or turbo? But I am gonna get aluminum heads and a cam. Thats the sure thing.
Anyways, I cant decide supercharger (less maintnance) or turbo? But I am gonna get aluminum heads and a cam. Thats the sure thing.
Junior Member
a turbo is not necessarily more maintainence than a blower. The real question is what you'll be replacing the TBI with, regardless of the route you take. What is your power goal? What budget are you dealing with?
Thats another decision I have to make. Either a TPI or carb. My goal is at least 450 hp. Budget wise it'll take a couple years but I just want to plan ahead. Im leaning more on the carb though.
Junior Member
My TA had a 305TBI engine. I swapped it out for a carbed 350 and could NOT be happier with the power gains I experienced. My next power adding project will be to go with the ATI Procharger setup. My eventual goal will be 500hp. I think you could get to 300+ with the engine swap, then use that as a solid base to add the SC.
If you were to bolt a SC on the TBI assuming it is in its stock configuration of 170hp you would need to run somewhere around 25lbs of boost to get close to 450hp. That is really unreasonable unless you REALLY build the engine to handle it. If you go with a crate 350 rated at 330hp (for example you could run 6-8lbs of boost with almost no other mods and the engine could handle it easily to reach your 450hp.
Figure roughly 7lbs of boost for 50% of your power boost.
PDG
If you were to bolt a SC on the TBI assuming it is in its stock configuration of 170hp you would need to run somewhere around 25lbs of boost to get close to 450hp. That is really unreasonable unless you REALLY build the engine to handle it. If you go with a crate 350 rated at 330hp (for example you could run 6-8lbs of boost with almost no other mods and the engine could handle it easily to reach your 450hp.
Figure roughly 7lbs of boost for 50% of your power boost.
PDG
Supreme Member
A well built 383 will have as much power as a mildy supercharged 305.
Cost would be close depending on routes taken, 383 would be less hassles.
I swapped to a carb on my old 305 and ran 15psi to it. The low end still sucked. My N/A 383 was much more fun and had about the same power up top.
Cost would be close depending on routes taken, 383 would be less hassles.
I swapped to a carb on my old 305 and ran 15psi to it. The low end still sucked. My N/A 383 was much more fun and had about the same power up top.
Well mine used to have 170hp but since we added the 2.5 in. flowmasters it now has an even 200hp. Anyways I think Im gonna go to the 383. I found a nice one in Jegs magazine that comes supercharged with a comp cam and alluminum heads for 9k. Not bad at all.
Supreme Member
What trans and rear are you going to go with?
Supreme Member
Quote:
Umm....sorry. No.Originally Posted by panzer
Well mine used to have 170hp but since we added the 2.5 in. flowmasters it now has an even 200hp. Quote:
Originally Posted by vwdave
Umm....sorry. No. umm yes? u dont believe me? Take it out with Big Dave at the dino. The other owner put over $1,200 bucks in the car. I dont have time to argue with you.
Quote:
Originally Posted by Batass
What trans and rear are you going to go with? Well Im leaning towards a 6 speed manual trans. and drop the gears to a 4:10. Have any other suggestions?
Senior Member
Quote:
Why didn't you get a dual 3" instead? That must be worth at least an extra 50 hp over 2.5".Originally Posted by panzer
Well mine used to have 170hp but since we added the 2.5 in. flowmasters it now has an even 200hp. Anyways I think Im gonna go to the 383. I found a nice one in Jegs magazine that comes supercharged with a comp cam and alluminum heads for 9k. Not bad at all. Member
I had a 305 crapper in my Camaro and did away with it immediately. I went with a GM Goodwrench 350 and topped it off with a quadrajet, 5 speed tranny, 2 1/2 inch Flowmaster exhaust and 3.73 gears. I am very happy with it. I am saving money for some more upgrades but it goes. So that would be my suggestion.
Trey
Trey
Quote:
Didnt have the cash. But thats another goal.Originally Posted by JoBy
Why didn't you get a dual 3" instead? That must be worth at least an extra 50 hp over 2.5". Supreme Member
If your going with a strong engine, I wouldnt go with 4.10 gears. They make the rear weak. If your going to keep the stock rear, I would go with 3.42. It has to do with tooth contact area.
Especially if your going with a stick, they are rougher on rear ends.
Especially if your going with a stick, they are rougher on rear ends.
Member
I have the 3.73's and they work just fine.
Ill probly go with either 3.73 or 3.42. As long as it puts fear in the hearts of Civic drivers. Then Im fine.
Quote:
Just bought and installed 3.5 stainless flowmasters. It has a lot more haul now. I drove up next to a riced out Civic hatchback and he reved a little so i put it in neutral and blew his eardrums. He got lower all redfaced and turned the corner.Originally Posted by JoBy
Why didn't you get a dual 3" instead? That must be worth at least an extra 50 hp over 2.5". Member
Quote:
SWEEEETTTTT!!! My 3.73's with my set up dusted a riced up jetta just friday. That was from about 30 mph. He came up and paced me and then tried to go. LMAO That was funny. I dropped it into 3rd and bounced. Pegged out in no time. So yes 3.73's are the way of the world my friend!!Originally Posted by panzer
Just bought and installed 3.5 stainless flowmasters. It has a lot more haul now. I drove up next to a riced out Civic hatchback and he reved a little so i put it in neutral and blew his eardrums. He got lower all redfaced and turned the corner. Supreme Member
Quote:
Your car is either weak, you're running the stock 225 tires, or you dont beat it. Everyone knows the strength of T-5s.Originally Posted by DCOWBOYS1975
I have the 3.73's and they work just fine. 3.73 isnt a bad gear, but 3.42 is a stronger gearset. If you're lookin to make more than 500 crank hp, you should be looking for a new rear for sure.
Member
Quote:
3.73 isnt a bad gear, but 3.42 is a stronger gearset. If you're lookin to make more than 500 crank hp, you should be looking for a new rear for sure.
Im not pushing 500 horse but why is my car weak???Originally Posted by Batass
Your car is either weak, you're running the stock 225 tires, or you dont beat it. Everyone knows the strength of T-5s.3.73 isnt a bad gear, but 3.42 is a stronger gearset. If you're lookin to make more than 500 crank hp, you should be looking for a new rear for sure.
Supreme Member
The best T-5s can't handle 300hp if they are driven hard.
Just because you have 3.73s and you havent busted your rear doesnt mean anything. Facts are facts. Im just saying you definitely arent making much hp.
This guy wants at least 450hp. Well past the reasonable limit of the stock rear. So, a conservative gearset is in order. It hardly has anything to do with gears in general, just the weak point in the 10-bolt rear.
Just a warning. No one likes to spend good money, and have your car break, or worse strand you, and not have the cash to repair it.
Just because you have 3.73s and you havent busted your rear doesnt mean anything. Facts are facts. Im just saying you definitely arent making much hp.
This guy wants at least 450hp. Well past the reasonable limit of the stock rear. So, a conservative gearset is in order. It hardly has anything to do with gears in general, just the weak point in the 10-bolt rear.
Just a warning. No one likes to spend good money, and have your car break, or worse strand you, and not have the cash to repair it.
Member
Quote:
Originally Posted by JoBy
Why didn't you get a dual 3" instead? That must be worth at least an extra 50 hp over 2.5". ....or you can get the 5inch duel system and add 90hp...
and some stickers are good for 5hp each
and a ***** spoiler is good for about 60hp

Member
Quote:
Just because you have 3.73s and you havent busted your rear doesnt mean anything. Facts are facts. Im just saying you definitely arent making much hp.
This guy wants at least 450hp. Well past the reasonable limit of the stock rear. So, a conservative gearset is in order. It hardly has anything to do with gears in general, just the weak point in the 10-bolt rear.
Just a warning. No one likes to spend good money, and have your car break, or worse strand you, and not have the cash to repair it.
Gotcha. Well the guy I got this from must have done something to the T-5 either that or it's gonna blow anytime, because I rod the $%^& out of it and it handles it fine. Like I said it ain't got 500 hp but I know that it is on the upper part of 350 hp. I want to get to 450 as well what would you suggest for a manual tranny?Originally Posted by Batass
The best T-5s can't handle 300hp if they are driven hard.Just because you have 3.73s and you havent busted your rear doesnt mean anything. Facts are facts. Im just saying you definitely arent making much hp.
This guy wants at least 450hp. Well past the reasonable limit of the stock rear. So, a conservative gearset is in order. It hardly has anything to do with gears in general, just the weak point in the 10-bolt rear.
Just a warning. No one likes to spend good money, and have your car break, or worse strand you, and not have the cash to repair it.
Supreme Member
T-56 will run you around 1500 said and done, a tko will be around 2200. Roughly.
Thre isnt much you can do to a T-5 strengthwise.
Thre isnt much you can do to a T-5 strengthwise.
Junior Member
Quote:
and some stickers are good for 5hp each
and a ***** spoiler is good for about 60hp
I know I'm a little late on this, but I was thinking just that as I read through this.Originally Posted by billybird
....or you can get the 5inch duel system and add 90hp...and some stickers are good for 5hp each
and a ***** spoiler is good for about 60hp
Or run no exhaust for 300HP!!! XD I had no exhaust on my 305 DOG and it just made the passenger seat warm, and got me sound violations.



