Do any of you have any hard evidence one way or the other as to whether or not siamesing the plenum to match the SLP siamesed runners is a good idea. It looks like it would be a great idea and seems to make sense, however when I called SLP with this specific question they reccomended against it. Now the guy I spoke with was certainly no rocket scientist so I would like to see if anyone here has dyno runs, 1/4 mile times, anything that would support or not support this operation.
I also considered epoxying up the runners so that they were no longer siamesed as I have heard repeatedly from some folks they are too big. Anybody ever tried this?
My motor has been upgraded front to back and should pull hard to 5500 and possibly beyond so I have got the breathing for it.
Info anyone?
Thanks,
Roy

 

Well, my dyno run is done. I made the same power wt and wtout the runners (247.8hp). The guy said I was running very rich and would probably gain a lot by trimming back the fuel. (Same as first test). Peak power went up almost 800RPM, though. FWIW, I also siamesed the runners all the way to the intake. The intake is my biggest limitation now.

------------------
Bob '89 Formula CC350
Last(lost)Member of the Elusive Great Lakes Crew
My car's homepage

 

I have the SLP runners and I did cut the spaces between the runners holes on the plenum, I even went as far as to port the runners. On the top side, the runners are already joined since the wall between them was remove by about 1" at the factory, well, I removed even more of that wall and also made the diameter larger. On the bottom side, the wall was there but I made it just like the top. After I was done, I polished all the runners. Wether it made a big differnce or not, I'm not really sure (I think so), but my car runs 13.50@104.27MPH.
You be the judge.

ps: if you think the car lost torque, think again. even though I have a huge cam in the engine with stock converter, I smoke the tires past the 60' at the track; on the street is a very long way, but somehow I still managed to get a 1.90sec 60' at Moroso Motorsports Park, FL

------------------
'88 GTA 350
Headers, catback, free mods, Xtreme energy cam, and intake pieces
13.51@104.27, but can run better as it is.

RAPTOR, the baddest bird on the planet
AIM HIGH!