5s top mount IC?, reasonable? Options

[crankyelbow]

I've been pondering the turbo route, and I'm amazed how readily available and cheap the ct26 turbo is - along with the proper manifold and other bits.

One big way to cut the costs, and something I always wanted to try in my turbo yaris, would be a top mount intercooler. The response should be amazing with the minimal piping that would be used in such a setup.

Given the layout of the motor, it would seem to be EXTREMELY easy to route piping, mount the IC... in fact it seems the 3sgte uses a top mount IC stock (as did the turbo yaris in stock trim overseas)... BUT...

What would be the approx boost limits given this setup? Clearly the air wont be cooled anywhere near as effeciantly as with a FMIC, but given a hood scoop/heat shield, what are the approx limits? Has this been done on a 5s before?

[lagos]

A top mount air to air intercooler just sucks. Its like having a BBQ grill on top of your engine.
You can do a water to air side mount, but then it wont be any cheaper then a front mount.

With todays prices and ebay specials, a front mount is the cheapest way to go.

[PR3M4TUR3D3T0N4T...]

A top mount air to air intercooler just sucks. Its like having a BBQ grill on top of your engine.

Death says that's going in his sig for sure

[TRD_Ian]

what about a 3s w2a ic? with a vented hood?

what about a 3s w2a ic? with a vented hood?

[presure2]

what about a 3s w2a ic? with a vented hood?

what about a 3s w2a ic? with a vented hood?

well, with the 3s having a center feed intake manifold, you dont really have the room to route the piping.
with the amount of work it would take to do it right, you could just do a custom w2a setup that would be just as if not more effective.

art is 100% right BTW, the stock 185 interwarmer is just about worthless, especially on a 6gc that dont have a scoop to direct air over it.

[crankyelbow]

With a scoop it would seem a good idea though? Particularly in the case of someone that doesn't want to run alot of boost.

Routing a FMIC is significantly more piping and cost than a top mount.

Perhaps I'll just have to blaze the trail?

[Defgeph]

Waste of time and money. Stick with water/air, or a front mount.

[presure2]

With a scoop it would seem a good idea though? Particularly in the case of someone that doesn't want to run alot of boost.

Routing a FMIC is significantly more piping and cost than a top mount.

Perhaps I'll just have to blaze the trail?

no.
they dont call them "interwarmers" for nothing.
guys back in the day used the alltrac top mount, and the supra side mount ic's as generic front mounts, which see LOTS more air than a generic scoop will direct over them, and even then they sucked.
like jeff said, stick with a FMIC or a w2a setup.

[lagos]

With a scoop it would seem a good idea though? Particularly in the case of someone that doesn't want to run alot of boost.

Routing a FMIC is significantly more piping and cost than a top mount.

Perhaps I'll just have to blaze the trail?

Honestly, if you cant afford a front mount setup, at todays super cheap ebay prices, then you shouldn't be trying to boost your car.

[crankyelbow]

With a scoop it would seem a good idea though? Particularly in the case of someone that doesn't want to run alot of boost.

Routing a FMIC is significantly more piping and cost than a top mount.

Perhaps I'll just have to blaze the trail?

no.
they dont call them "interwarmers" for nothing.
guys back in the day used the alltrac top mount, and the supra side mount ic's as generic front mounts, which see LOTS more air than a generic scoop will direct over them, and even then they sucked.
like jeff said, stick with a FMIC or a w2a setup.

Defined "sucked"?

I can definitely see a benefit coming out of the large reduction in piping length, feet less of charge piping HAS to significantly increase responsiveness... and without high boost levels I just don't understand why a FMIC would be deemed necessary?

Alot of stock turbo cars run a top mount, there must be a reason for this.

A good debate on a subaru forum:
http://forums.nasioc.com/forums/archive/in...hp/t-39927.html

Really, on paper, what is the benefit to running a FMIC if the boost levels won't exceed 10psi on a 5sfe? Are we talking any REAL gains? It seems to me that if a top mount *works*... as in... it suffeciantly cools the air for safe operation... it would be a BETTER choice in all aspects.

Thats to say, if there were a top mount setup that made 200whp... and a front mount setup that made 200whp... the top mount would be faster in most situations. Worst case for top mount is along period of idling... but as long as there is a scoop of some sort the increase in response and less pressure drop from turbo to intake SHOULD make the top mount car a little quicker, kinda like comparing a turbo car to a n/a car... n/a with the same torque curve would be faster because the power is available immediately.... add extra cooling to a top mount in whatever form you choose and IMO thats best case scenario up to XX psi.

[presure2]

it suffeciantly cools the air for safe operation

IMO, no, an alltrac mount is not safe for a 5sfte, even at low boost levels. (just ask any alltrac owner how much they like theyre stock TMIC...lol)
throttle response is negligable.
the diffrence between modding a alltrac TMIC to work on a 5s, and just building a cheap FMIC setup is small.
its not really worth taking the chance on IMO.

[lagos]

Defined "sucked"?

You can put an egg on it and fully cook it.

This is not the same thing as the subaru top mount. Go look at those cars. Their topmounts are mounted at the back portion of the motor. On our cars they sit right on top of the hot engine, and just heat soak.

If you want all the benefits of throttle response, then setup a water to air system. Same benefits without the heat soaking and you dont have to cut up your hood.

[crankyelbow]

Egg cooking IC's are no good

I'll examine a water/air setup... and actually pop the hood and stare for a while.. see what crazy ideas come up... learn what numbers to run and run them, see the limits of all the above setups.

Sub $300 for water/air... not unreasonable at all! .1psi pressure drop sounds VERY nice also! Now THAT sounds best case to me... the piping would be even easier with water/air too... but there is a little more effort to be put into routing the lines and heaet exchanger... also weight too, but not very significant.

Much research to do indeed! Just trying to think outside the box with this build, try something new and preferably come out cheaper in the end

This post has been edited by crankyelbow: Mar 29, 2009 - 3:06 PM

[eggman40]

Defined "sucked"?

This is not the same thing as the subaru top mount. Go look at those cars. Their topmounts are mounted at the back portion of the motor. On our cars they sit right on top of the hot engine, and just heat soak.

x2

I kept a top mount on my 3s for a few weeks till I could afford a FMIC. IT SUCKED! It was always hot, you couldn't even touch it it was soo hot. subarus fire piston to the sides so the "header" pipes are far away from the ic and dont cause heat soak.

also IIRC the 5s throttle body comes out the side and not out the middle like the 3s.... so you would have to put in some really hard bends to get it to mate with the charge side of a top mount (either a2w or a2a)

why not get an intercooler that has both the charge pipe and the intake pipe on the right side??? that would shorten the length of pipe you need, especially if you clock the turbo.... and since you say your not going to boost very high, then you dont need to go through the hassle of making the a2w system work. AND it would be waaaaay cheaper....


I think the difference in performance bet. top or front mounts would be marginal at best with such low boost levels. not worth the thouble IMO

[crankyelbow]

why not get an intercooler that has both the charge pipe and the intake pipe on the right side??? that would shorten the length of pipe you need, especially if you clock the turbo.... and since you say your not going to boost very high, then you dont need to go through the hassle of making the a2w system work. AND it would be waaaaay cheaper....


I think the difference in performance bet. top or front mounts would be marginal at best with such low boost levels. not worth the thouble IMO

I was considering this today actually... there is plenty of room under the hood to run the IC to the side of the motor... with a proper scoop/vent or some other masterfully designed system, it would seem to be a great way to go.

11psi would be the very top end of my goals... and I'm guessing a side mount would still do well @ those boost levels.

Still a long way away... but the more thought put into something the higher the chance of success