i own a 91 rs 305 tbi man., and have read a few things on gaining horsepower, but i dont have the big bucks to do much, so i was wondering what i can do to gain the hp i need. i have a super ship in, and am working on getting headers with a free flow dual exhaust, and a performance tune up, but as for the throttle body i havent the slightest on what i can do to that, beside get some overly expensive bigger one, so what can i do? go with the K&N xtreme air lid on my K&N?? any help is awesome, thanx

~~mr

 

My friend has a 91 with tbi, so far he did 3.73's with a posi, Borla cat back, and a underdrive pulley. WOW what a difference it made. In a weird way i like the thought of making 305's fast.

 

teh tech articles are teh place to start. ultimate tbi mods, open element, and diy afpr.

after that you can start looking at other stuff

later
tim

 

what size underdrive pulley will i need to get more power out of the engine?

~~mike

 

I've heard from just about everyone that has put on underdrive pulleys that the difference was not noticeable, I'd say spend your money elsewhere and don't bother with the pulley. You're going to want to do the Ultimate TBI mods in the tech article section first off, then go for full 3" exhaust and gears and posi, then see what you want to do after that, my .02.

 

what sort of gears should i put into the rear end(i assume those are the gears you are talking about) and where would be the best place to get them

~~mike

 

Yes I was speaking of rear end gears, and with that manual tranny I would go with 3.42's, at least that's what I did, but others will say 3.73's; either way your going to get a good gain. The posi unit you can get for $99 from SLP. I found my gears and posi on ebay though, you can find gears pretty cheap there.

 

My experiences.........

Underdrive pulleys are pretty much worthless, I have them, nothin too special I saw slim to no gains

Ultimate TBI mods yes

As far as the Xtream filter top, I have one and I like it. It is a tight fit though, really close to touching the hood.I did notice a small difference though.

Hope this helps a bit

 

Underdrive pulleys are useless. Yea wow .. they look cool , but make my lights dim at idle and waste 150 bucks.

I second the 3.42's on a manual ... its a very good combo that i have running.

I don't beleive the x-treem lid it worth it. The way that the Tb gets air is through the front and sides mainly. Theres a big injector pod on the top that is in the way of letting the air go through the top. A 14x3 open element is plenty

 

I have a 305 and 5 speed manual tranny also. I've been wanting to upgrade my rear end gear. How hard is it to convert my rear end to 3.42 with posi? What do I need to do first?



Thanks

 

First get the new rear built and just swap.
It's a weekend opperation.. took my an 2 friends about 30 hours but we did the brake's too... do a search