I'm wondering if anyone has tried siamesing the stock lower intake with a set of siamesed runners and plenum. I'm thinking it may be a somewhat easier solution to the top-end restriction of the tpi system. Tecnically that's what gives the TPI it's flow restriction correct? I'm thinking siamesing it until just before the port split to the heads. That is unless I could bolt the intake up siamesed all the way from the runner inlet to the heads. Has anyone tried this?? It's either this or shell out the cash for a HSR. I'm kinda strapped and have another TPI base laying around, so maybe I'll try it, unless I hear otherwise.

Chris

 

I siamesed mine about 1 1/2" down, along with smothing the transition with the stock runners, and really opening up the upper plenum. I did this at the same time I installed my cam. So Its kinda hard for me to judge the siamesing job by itself, but now my car has lost its low in grunt, but once I get around 3000 rpms, holy-****, does it wake up. I now can shift, with full power, at 5500 rpms, when before, of course, it was dead after 4000.

 

P.S.

I also installed the 3.42 gears the next week, and that help'd recover my lost torque at low end, for the most part.

 

So it does infact help. I wonder if it would help to go even closer to the port for the heads. I would like to think it would work as it for all effectivness eliminates the TUNED in Tuned Port Injection. Anyother opinions??

Chris

 

i siamesed my stock intake all the way to the head. left the divider at the head side. used stoc krunners. picked up mid range real good. but because of the stock runners, it still peaked at 4800. the i switched to the slp runners and edelbrock base. i siamesed the runners. picked up 35 hp above 4500. also i changed from the lt1 to the zz4 cam.

 

I've got an extra base laying around so once I get the computer close I'll slap it on the dyno and do a compro for everyone, just to see it it makes a difference.

Chris

 

Did you see the recently revived?

https://www.thirdgen.org/techbb2/sho...hlight=siamese

I've been too busy with work to do any further experimenting.

 

WOW!!! Madmax I feel kinda stupid now seeing you did that over a year and a half ago. I only thought of it seeing as I'm broke and have a huge cam in an essentially stock motor. I figured it would help out the top end if I got rid of most of the runner length. So combine the ported intake, plenum, some siamesed runners, and a set of severly hogged out L98 heads with 2.02/1.60's and I figure I'll save tons over a Stealth Ram setup, or even an LT1 intake/MiniRam. I'm gonna get started on it tomorrow to see how long it's gonna take and how far I can get the runners down to.

Chris

BTW you can check cam specs in the sig.