3.1 Ideas

[3.1cutlass]

So i wanna get a little more power out of my 3.1 cutlass. I have a CAI and thats it. I am gonna do an exaust soon. What are some other low cost things i can do for some power here and there. I know there is the throttle body option but i need some explanation.

[a1990cavalierz24]

There aren't really any cheap mods that aren't going to get you any major HP gains. The only thing IMO that would make a noticeable difference on your motor that doesn't cost too much would probably be an UDP (underdrive pulley).

[alainman15]

hey is there a cooling line (for antifreeze) that run to the tb. i thought i saw 1 run to it the other day. if there is 1 u might want to remove that.

[3.1cutlass]

ya i know of that i have had to replace it. Should I just run the hose long somwhere or short to bypass? More explanation on the underdrive pulley please. What about a bigger TB? What would work? I amnot looking for major hp but just alittle here and there.

[bracketracer]

As for the TB heater bypass, I just took the "l-Bend hose," bent it a little more and put it from inlet to outlet. This hose isn't under much pressure at all, and it has held up for about 4 years now for me. I am actually debating removal of the entire metal coolant line and adding block-off plates if possible, for my new race motor.
The Underdrive Pulley is smaller than stock (and lighter). I believe that the idea is too minimize power loss drawn by the accessories. It doesn't actually "make any power," but it reduces power loss by the accessories, which should put more HP to the wheels.
A bigger TB is an option, but not cheap or very useful on a bone-stock engine. There is the initial cost of the TB, plus you have to get your upper intake ported to match. If you do the install and porting yourself (not too tough if you have tools and basic mechanical aptitude), it will still cost you over $400 in parts (TB, gaskets, etc). I added an FDP 62mm TB to my Sunbird 4 years ago. Other than being able to hear the slight whistle (almost sounds like Supercharger whine) from air crossing over openings in the TB, I didn't notice a huge gain. It will help more on my new motor that will have ported heads & intakes and headers.
I still think the most "bang-for-the-buck" is in a custom chip. Talk to Ben, I'm sure he has one. Even my HyperTech ThermoMaster (which most people think sucks) gave me a gain of between .4 and .5 in ET, and a couple of MPH. I plan to have Ben burn me a custom chip which I am confident will be better.

[torq455]

i have the UD pulley and noticed more go from 4Krpm to 5300rpm. as for my 62mm TB? well in order to port properly, you have to go as far in as possible. in which case, you get the neck very thin. i can't believe i didn't go through! you can see my mods below, and i tell you, that TB was a VERY nice gain! yeah, that whistling is cool too. that TB heater bypass you won't notice any seat of the pants gain. but it will help to keep the air entering the engine a tad cooler. no one knows how much this helps, but i figure it can't hurt.

[3.1cutlass]

How big of an underdrive pulley would be best?

[3.1cutlass]

i have access to a 2.8 and a 2.5? Who is ben?

[bracketracer]

Ben owns and runs 60degreev6.com Store. Click on the sign at the top of this page.

When I ported my UIM for the 62mm TB, there were two areas where I literally only have 1mm of material left. You couldn't put any bigger TB on the stock intake without adding material to it.

[torq455]

i've heard of a few people that put a 65mm TB on. not sure how they got the gasket to seal since there virtually is no mating surface left!

UD pulley for our cars are not pleantful. fwdperformance.com has them and has been out of stock for some time. their UD's are 18%. another company, aspperformance.com had them too. theirs is 15%. either way, i would recommend raising the idle up by 100rpm to compensate for the loss in accessory drive to maintain the alt charge and coolant flow. maybe since the older 3.1's idle at 650, it would be even better to go up 150rpm to get a little ahead of stock idle.

[3.1cutlass]

k so what about a 62 mm tb?

[torq455]

that's fine, after all, it's what i have.

[3.1cutlass]

so if i get another manifold and have it bored to 62mm and a 62 mm tb. Where could i get a 62mm tb? Junkyard?

[torq455]

never. those were custom made like the 62 and 65mm TB here a long time ago. i don't know anyone who makes or is willing to sell theirs that still wants to keep the genII top end. i only got mine due to a guy doing the 3400 top swap. lucky me!