89Formula350WS6

What kind of {horsepower - torque - E.T. (especially 1/8th mile) & MPH} gains can I expect from porting the plenum behind my throttle body, smoothing the steps just inside the exits/entrances of the stock runners, and any other minor smoothing and cleaning up of casting irregularities? I've heard that there was a lot that could be cleaned up on the stock parts.

Anyone using SLP runners on an otherwise stock TPI unit? Do they hurt lower RPM TQ? If so, is the top end HP on a stock L98 worth the trade off??
I saw on here that it helps to siamese the plenum (and maybe the base) to match, but I think I'll wait til I have a spare of each before trying that.

How/should I relocate my Intake Air Temp Sensor? I heard about moving this to my air cleaner ducting, but I'm not sure where the sensor is, or if this is a good mod or not.

I'd love to hear some times for mildly modded L98's. Is a 9.50 in the 1/8 good for my car? (stock 89 Formula 350 with 3.70 Nine bolt & all the 1LE stuff except for the big front brakes & it has A/C.) How does it compare with the quarter mile?? My 60' times are 2.22 seconds on 245/50-16 cheap radials spinning through alot of first gear.


Another LONG POST, but I'm new here. I'll get the hang of the search soon I hope. Plus I'm covering most of my ??? in just a couple posts. Please excuse.
Thanks in advance for the help,
Jason
P.S. Just imagine all the stuff I'll be asking if ya'll talk me into buying on of those chip burners!!!!!! Looks awefully interesting.

egmonster

Seems like your time is pretty high... Get some rubber and you should be quite a lot faster... Completely stock runners + completely stock plenum + siamesed base 3" = 40hp gain dyno proven with a little loss in low end grunt (negligable...). You can also siamese your plenum which is a little easier to do. Do a search on this board in the article section and also through the forums and you will uncover a lot of useful info. I am just about finished siamesing my baseplate and I am getting excited to put it on... it's taken me a while since I have not that much time to do it but it should be worth it. I only did about 2 1/2"... I want to get some AS&M siamesed runners but they cost well over 400 dollars and at that price I could just as easily buy myself a new stealthram... of course it would look *much* less stock then (and I really like the stock look of this engine and intake and I like torque too what can I say I'm no speed demon ).

jd13

I ran a 9.0 with my setup in my sig. Just that. I have headers and a different exhaust system now, but no times on it.

5SIZ

I have fully ported my plenum & yes there is a bit of work that has to be done to it BUT don't expect to see any Huge HP increase. The main reason why I did mine is to get a little more top end "breaths better" seeing as how our cars run out of breath @ 4,500-5K rpm range stock, we need all the top end we can get lol.


The IAT is screwed in under the plenum & Yes, it is a wise decision to move the IAT to a cooler spot, seeing as how all that you get is hot *** readings since the IAT is basically sitting in an oven. It's good to "cheat" and fool the ecm to think its sucking in cooler air. if you have gutted you intake but left a good inch or 2 left on the filter housing you can put the IAT right under the filter.

P.S. I would invest in buying a new IAT and leaving the existing one in it's place.

89Formula350WS6

jd13,

That 9.06 @ 76.39 looks like it is mostly through the first 60'. That's a full two tenths better than my 60 ft times. I'm sure the underdrive pulleys & stat helped too, but how did you pull off those 60' times stock? Any rear suspension work or drag radials?

89Formula350WS6

5SIZ,

Thanks for the info on the IAT sensor relocation. I don't know why I hadn't thought of just getting a new one & leaving the old one in but unhooked. Sometimes we just want to complicate things huh?