[Bob_Myers]

Originally posted by Lon Danley:
So I would think at this point in the intake system you'd be safe to go back to 2.5" piping and suffer no losses.

You are basically right that no matter what you make a cross section change at the intercooler ... What I want to do is minimize losses as i'm sure they are there.

Originally posted by Ted B:
I hope that helps.

A lot Ted! It more or less convinced me I was thinking right with staying 2 1/2"

As I said, not that power level for sure, but when I went up to 3" it had no affect as well. It was actually done as a step on the path to blow through MAF, but I put the tubing and TB in with no changes and went to the track.

What has had me thinking is "the world is your plenum at WOT" kind of things. The other thing is length of pipe factors, but I'm propbably looking too much now ...

Originally posted by don33:
it just seemed like the right thing to do. did it add any HP ? :dunno: I am pretty sure it did'nt loose any.

And that's the other argument for sure

It was also interesting that Bo has posted several dyno combos in the proven combo thread north of 400 rwhp that he shows with a stock TB ... Again, I have the 65mm but would like ot get back to what I reember for the response of a stocker (more input for cruise).

[Bob_Myers]

Btw - no worries on cutting. I have multiple resources either way

[bw_krupp]

My thoughts, based on no technical background at all, just opinion, are as follows: Just run whatever fits best. If the turbo outlet is 2" and the intercooler is 3" (do what I did) and run 2 1/2" piping in between so you can run 2-2.5 and 2.5-3 couplers. Then run a 3-2.5 coupler on the other side to the throttle body. (or do what I did and run 3" all the way with a bigger throttle body just for ease)

[grasshopper]

I just switched from 2.5" to 3" on the hot side, and stayed with the 3" on the cold side, switched from a 65mm a 75mm throttle body. I also went from 3" inlet to the turbo from the head light bucket to a 3.5" pipe.

My findings is My car liked it, Stalling the car is faster, and with just the above mods done I had to add 16% more fuel across the whole fuel curve.

:dunno:

[Gary M.]

I've always been a fan of keeping diameter transitions as smooth and long as possible, within the practicality of fitting it all in the space available. It helps if stuff is lined up nicely, cause if it isn't, it gets complicated.

I built a 15" long tapered tube to go from a 2" compressor outlet to a 2.5" IC inlet, I cut a long wedge from a length of 2.5" Stainless tubing, hose-clamped the gap back together, fusion TIG'd the seam, then TIG'd in an elbow for a bypass valve.
http://i301.photobucket.com/albums/nn78/...1292872503

The transition from the 2.5" IC outlet to 3" throttle body was done with a 2.5" to 2.75" 45º Silicone el, a short length of 2.75" Al tubing, and a 2.75" to 3" 45º el.
http://i301.photobucket.com/albums/nn78/...1292872542

I have no idea how all this is going to work, it looks nice I guess, and I'm just trying to make the plumbing as efficient as possible.

[TurboRay]

Originally posted by Gary M.:


I built a 15" long tapered tube to go from a 2" compressor outlet to a 2.5" IC inlet, I cut a long wedge from a length of 2.5" Stainless tubing, hose-clamped the gap back together, fusion TIG'd the seam......

WOW......Your engine compartment is gorgeous, Gary! I also admire your fab skills and innovation to make that long tapered tube. But, I've just gotta ask - after all that work - why did you use "hump connectors" on either end, that arguably diminish the "smoothness" of the transition? :dunno:

C'ya - RAY

[nagelandy55]

Originally posted by TurboRay:

Originally posted by Gary M.:
[b]

I built a 15" long tapered tube to go from a 2" compressor outlet to a 2.5" IC inlet, I cut a long wedge from a length of 2.5" Stainless tubing, hose-clamped the gap back together, fusion TIG'd the seam......

WOW......Your engine compartment is gorgeous, Gary! I also admire your fab skills and innovation to make that long tapered tube. But, I've just gotta ask - after all that work - why did you use "hump connectors" on either end, that arguably diminish the "smoothness" of the transition? :dunno:

C'ya - RAY [/b]

Ya, awsome engine bay but those hump hoses seem counter productive to what you're trying to achieve.

[Lon Danley]

x2 on Gary's idea for the long transitions. We've used the flowmaster collectors on the exhaust that are the same idea with noticeable ET gain.

[stott]

with all the air that is flowing through the IC piping, i highly doubt that hump hoses/2.5"-3"transitions or 3" piping over 2.5" makes any measurable difference.

[23reasons]

hump connectors are good for vibration and allow some play/tolerance with moving parts....