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top mount intercooler

4503 Views 35 Replies 14 Participants Last post by  DKJones96
well, i did the whole search thing, and i might have missed it, but i didnt really see any one mention a top mount.

i was doing some looking around under the engine bay, and at my friends spare intercoolers that he had laying around.
i took off the plastic pipe that goes over the engine, and i tried a couple old beat up intercoolers until i thought i had one that fit, and i set it in place, then closed the hood.

no foul noises... no bent hood... no dented intercooler.

he isnt sure what it came off of, but hes going to take a good hard look and try to find out, but the intercooler was about 12"x6"x2.5" with 2.75" inch inlet and outlet.

i think when i turbo the car, unless someone warns me away, im going top mount.
ill use my spare hood to mount some kinda subaru hoodscoop for air intake.

going to sleep now, but im kinda buzzed about this.... :)
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I don't want to scare you away from trying it, but didn't the all-trac celica turbos have problems cooking the internals on thier top mount systems?

Plus, I think you would get better airflow in the font.


83 p-type
79 5mgte 4x4
My cousing has an All-trac turbo (its the Celica Body that kinda mirrors the Mk IV body.. wanna say its a 92 or so but not sure) with a topmount and he has alot of problems with it. Hot weather, after sitting in traffic for any length of time, the intercooler gets heatsoaked BADLY... sometimes in extreme cases to the point of causing detonation even with the ECU pulling as much timing as it can... Now the Scooby WRX/STI guys all have top mounts and I haven't heard of them having this problem, tho I do see more than a few of them switching to front mounts.. Maybe thats a route you could go for info too.. the scooby guys.
Go to an autox. Everyone with a topmount (especially the scoobies) is out there with a garden sprayer before and after each run.

Dont do it man... You wont be able to retard timing enough to handle it imo.

unless its a air-water i/c, not really worth it. i have an air-water i/c from an alltrac i was thinking of usinging for a future 5/6mgte project. dont know yet.
thanks for the warnings and advice folks, but i did some thinking last night/today at work, and well, i was thinking about the heatsoak issue most of the day...
i kind of feared that, and my friend wondered if it would be possible to make a box, kinda like the shaker hood scoops on the old 429 boss cobras, and i think the hemi superbees.

im kinda considering getting the power bulge section of the hood raised up and inch or two anyways, so now ive gotta figure if i can build a cowl vent/heat shield that will work well enough to keep it nice and cool.

ill probably end up doing a conventional front mount until i get it running reliably, then trying the top mount.
i figure since ill have access to a mig welder, and my dads got like 20 years of welding experience, it should be good practice, doing the pipes a few times :)

now to find a good source of ceramic insulation.... :?
Also I thought it interesting that the kit that was for sale on ebay just a little while ago had an intercooler mounted over or in place of the air filter. Very small intercooler though.
Very small intercoolers arent going to cut it. Keep in mind the size of engine these intercoolers you are looking at came from. Show me another car with top-mount more than 2.5L... MR2, Alltrac, Turbo2, WRX. Imo, a better "cool" previously un-documented project would be a water to air intercooler. They aren't too expensive if you keep your eyes open on ebay. Also, there is a space in front of the power steering pump where a 5" diameter air-water intercooler would go nicely.

I used to rally a WRX (I was nav) so we spent a LOT of time with the scooby guys. Top mounts work ok on those cars, but anyone pulling searious boost and power upgraded theirs, the ones that stayed with top mount has sprayers but most went front mount.
SCC just upgraded their top mount on their WRX in its last tech article. They went to a bigger top mount and they lost power! Heat soak got worse, I don't think they figured out why exactly. But yeah, it would be great to shorten all that plumbing to keep turbo response up
I saw that article and showed it to my friend with the all-trac, who just bought a larger Top-mount.... 10 minutes later he was returning it to the vender..LOL.

As for shortening the piping... go with a water to air setup... thats the shortest setup you can get with an I/C...aside from no I/C at all that is.
maybe a top mount water-to-air thats insulated as well?

im still liking this project, and if its feasable, id like to do it.
i was talking to a "turbo guy" at a shop the other day, and hes putting a vee mount IC and rad on an 87 supra with a 3sgte (i know... goofy engine/car combo).
hes got that IC insulated up nicely, and a vent cut in the front portion of the hood, with ducting to take the air right in and through the IC...

im thinking ill do a front mount until i see this guys car up and running, then ill decide on a top mount for myself.
Top-mount IC

I would think that if you could insulate from the hot air from the rad, and heat off exhaust, engine, it should work. I am doing a 5mgte this winter, and was considering tall hood scoop with flow-through for IC.

Anyone sketched out any ideas on this?

Barry... most water to air's are top mounts... or at least, the exchanger that is in the intake track is... and then the coolant cooler is like a front mount...

Ken... Celica All-tracs are set up like that from the factory... and while its ok on short trips, the IC gets a stupid amount of heat soak on any trip longer than 30 minutes...especially in the summer months. All in all the only real way I would consider a top mount was if it was the choice between that, and no IC at all... and even then it would be a toss up...
i keep thinking about this...
id love to have more money for the turbo project, at the moment im concentrating on doing it safely.

in canada our average temps are also a lot cooler than most of the states, i think in fall/winter/spring, a top mount with some fresh air flow would be the devils trip... but in summer itd be tougher to make happen.
top mount IC

Why not have a small electric fan to keep air moving over the IC?

i think that you would still get heat soak, because if you have a fan, its probably going to be pulling air from the engine bay to flow over the i/c.

the only way i can see this working is if you make up some kind of ceramic insulation for your i/c, and seal it VERY well to the hood.

ive been going over this with a few friends, and they say its doable, but far from perfect, unless your willing to spend a ton of cash on the project, which isnt really one of my goals.
And there you've hit the nail on the head... top mounts are do-able.. and able to keep pace with FMIC's in terms of efficency of operation.... however the cost amount to do so it ridiculous compared to a FM.... Why spend 3K getting a top mount setup when you can spend less than 1K and have something that works just as well?
If you plan on a 3" cowl hood with a ghetto scoop hacked into it, with an overly complex and overpriced IC setup that will be less efficient than a Spearco, go for it. That IC is too small. What is your objective in doing this? To be 'unique'?
well, i originally thought itd be a really good way to get considerably quicker throttle response, and to eliminate a lot of boost lag.
i was also thinking more along the lines of highway driving, when the air flowing over the i/c would actually have some benefit, but i figure it wouldnt help much in the city.

mostly it was an idea and i wanted to pursue it until I was convinced of why it couldnt be made to work, and all the fine folks on here told me it wouldnt, but some engineers told me itll work great, but i better be prepared to toss $3000+ at the problem, which is convincing enough for me.

and not that i dont trust the people on this board, but hey, research is free :)
and let us remember that no one was using the mkIII trannies simply because Reg Reimer told us it wouldnt work...
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