Top mount intercooler.

[panel]

Vee Dub Nut.....two questions.....I always thought the BOV should be as close to the TB as possible ? And what was the reason and/or engineering behind running a 'Y' intake as opposed to a 'T' style intake manifold.

[nbuscemi]

Having the BOV close to the TB is "supposed" to improve boost response between gears. From my research it ultimately doesn't matter. If you look at modern turbocharged cars, most of them have the BOV or bypass valve integrated with the compressor housing like the VW 2.0T does.

-Nick-

[Vee Dub Nut]

Vee Dub Nut.....two questions.....I always thought the BOV should be as close to the TB as possible ? And what was the reason and/or engineering behind running a 'Y' intake as opposed to a 'T' style intake manifold.

Hey Panel

RE: BOV location:

I picked pre-intercooler primarily because I intend to still add some provision for water/meth injection downstream of the intercooler (if/when i really lean on the car), and I simply wanted to the BOV to be sufficiently away from that point as to not vent any water/meth out of the intake during shifts/blow off events.

I did a bunch of reading about ideal BOV location, and it seems to be pretty split into two camps: 1) as close to the throttle body as possible, and 2) as close to the turbo as possible. Both have their arguments as to why. In practicality, even OEM's have them in a wide range of locations/configurations, and I just don't think it matters as much as we tend to think it does, so long as you have one in there.

RE: Y vs T

In general a fabricated Y should have a lot better flow coefficient than a hard 90/tee. Since I'm injecting fuel at the plenums out at the heads, I opted for the Y to make that transition behind the throttle body to be a smooth as possible for the air flow. I've read that for draw through setups (or other setups that inject fuel before that part of the intake), that the T is preferred to introduce more turbulence to help with fuel mixing. No first hand experience with that though. I've used a hard tee on my old port injected EFI turbo setup in the past, and just opted to fab up a nice smooth Y this go around. Another one of those things that I think matters less in actuality than we tend to think, but technically the Y should flow better.

[Vee Dub Nut]

Having the BOV close to the TB is "supposed" to improve boost response between gears. From my research it ultimately doesn't matter. If you look at modern turbocharged cars, most of them have the BOV or bypass valve integrated with the compressor housing like the VW 2.0T does.

-Nick-

Yea, that is the same justification I saw for BOV close to the TB when I researched it.

[nbuscemi]

I just noticed your signature... are you located in Texas?

[Vee Dub Nut]

I just noticed your signature... are you located in Texas?

Was.. Born and raised there, went to A&M, and the wife and I lived in San Antonio after school up until 2018. Now in the greater Atlanta GA area (where the wifey is from).

[Wally]

RE: Y vs T

In general a fabricated Y should have a lot better flow coefficient than a hard 90/tee. Since I'm injecting fuel at the plenums out at the heads, I opted for the Y to make that transition behind the throttle body to be a smooth as possible for the air flow. I've read that for draw through setups (or other setups that inject fuel before that part of the intake), that the T is preferred to introduce more turbulence to help with fuel mixing. No first hand experience with that though. I've used a hard tee on my old port injected EFI turbo setup in the past, and just opted to fab up a nice smooth Y this go around. Another one of those things that I think matters less in actuality than we tend to think, but technically the Y should flow better.

I think the reason a T works so well in reality might just be that flow in the manifold (and headers) is not one-way all of the time.

[Bruce.m]

Only recently fully understood the impact of turbo exhaust manifold back pressure vs intake pressure and how it affects camshaft selection. Definitely an “ah!” moment.

Although maybe that’s not relevant to your point

[Vee Dub Nut]

Well, I figured I'd update this thread again with another re-configuration of my top mount intercooler setup. This is actually the third intercooler and mount setup I've made for this car using this same Summit Racing core. For those that remember me from way back in the heydays here, you're probably not surprised that I've continued to build/rebuild my car and setup (and sell off my old parts) since the last update I posted in this thread

Just figured I'd show that with some creatively (and a bit of plumbing), this top mount intercooler can also be used with a dual ITB setup.

These are 42mm IDF throttles from the VWSpeedShopUK. A little difficult to see back there, but I fabricated the plenums on top of the throttles from 3" tubing. Of course all the rest of the plumbing was fabricated by me to suit.

The setup also got a cylinder head change and (another) cam swap. So far I'm very happy with the end result, and maybe just maybe, I'll leave it alone now (except for some more changes to the downpipe I want to make, and I've also been thinking about... )

[Wally]

Nice! I did something simulator and thinking about the benefits of a dual core intercooler with central ‘intake’ as used on some V-blocks with twin turbo’s.

[Vee Dub Nut]

Thanks!

I also looked at those dual core twin turbo coolers when I was considering the path with ITBs, but I didn't find anything that had dimensions that would work without some major customization. In all, I'm very happy with how this relatively cheap off the shelf cooler has worked out, and was stoked that I managed to still be able to plumb it to the ITBs when I made the induction change.

Major props to Nick who shared his original build and results... This is a solid intercooling option for these cars IMO

[GARRICK.CLARK1]

Just looked at the pic in the 1st page. I had an intercooler like yours on my bug. All the pipe work and the big cooler created a huge flat spot, as the turbo couldn't fill the pipeing and the cooler fast enough. So the balance between boost/fuel/rpm was off. Was undriveable and got taken off. So. No intercooler. Just water injection and less boost.
Good luck with it.
Ymmv

[Vee Dub Nut]

I've used this Summit Racing intercooler for ~year with my single throttle body intake as posted back in page 2 of this thread before changing to the ITB setup I just recently posted. I've had zero issues with the volume of the cooler/piping causing any noticeable impact on transient performance.

Certainly with the more intake system volume to fill, there is some potential impact to transient pressure rise in the intake. But I'd argue there are a ton of other factors in the engine combo and tune that are much more impactful than the presence of an intercooler.

[Wally]

I am in the proces of redoing the intercooler set-up.
The idea is to have the weight better distributed and keep the flow paths smoother, needing less bends.

Since I have the parcel tray reversed, there is extra room inboard. Rear side windows have air scoops that come Into the engine bay. Also have WMI. Hope its enough..
What you all think? Still hopeless since its not outboard?

Hope the picture link works.

[Vee Dub Nut]

It will be interesting to see how it works!

If your scoop on the rear quarter windows can effectively capture and route some air to it, I don't see why it shouldn't.

I also feel like none of the rear mounted intercoolers are ideal in terms of there air flow, and part of their benefit just comes from their thermal mass that absorbs the heat when on boost, and then (slowly) sheds it with the air flow it does get over the remaining time.

Keep us posted!