elmo505

does anyone know if there is much performance increase with a front mounted intercooler if so is it much better than an aftermaket tmic??

New_scooby_04

iTrader: (4)

I stand to be corrected on this by the more knowledgable but.....

Its won't increase performance by itself per se i.e. it won't make a 225ps car develop 280ps or anything like that. What it does is keep the charge temps down particularly on days with high ambeient temps. As temps increase the ECU has to retard ignition timing to prevent detonation, which means the car won't be delivering its full potential. The location of a FMIC means that its less susceptible to heatsoak from the engine and it's much more efficient than the TMIC when high speeds (100+) are involved as the air tends to miss the TMIC.

Using the above example, it lets a 225ps car develop 225ps more of the time and under conditions where a car with a TMIC would loose power.

The other advantage is that the lower charge temps allow engine maps to be adjusted to take advantage of the cooler air, which is what will give you the performance increase over std.

Whether you need one or not depends on the state of tune your car is in really and the model year. The TMIC will be fine for most peeps, I'd suspect.

NS04

pippyrips

i've been told they are not worth it until you start pushing in excess of 370bhp +, infact i think they can give you more lag???

On the + side they do look good!

New_scooby_04

iTrader: (4)

AFAIK, that very much depends on what MY you've got, the earlier TMICs were quite a bit less efficient that the latter ones I believe. I think 370 might be pushing it a bit on the std one though :-)

I'm also informed that with a good FMIC, lag increases are very marginal.

NS04

j900ase

I have a new age STI with APS Front Mount, before front mount max power was about 340bhp (WRC mapped), so fitted front mount.
No lag noticed driving but boost allways there due to lower inlet temps even when we had 32c day in summer.
Had another remap gained 10 bhp (sports cat and turbo limit now).
But be wary i have Defi,s fitted and before FMIC coolant never went above 105c, after FMIC even idleing temp allways around 100c takes 40mph+ to drop coolant temps. Oil went roughly 10c higher than before.
(My Defi temps wired independtly of car temp gauge which never moves from middle position 80c to 110c)
There is a fix for this, Zero Sports racing thermostat (coolant drops at least 10c) Zero Sports cool rad and Rad cap 1c - 2c drop above 40 mph.
Also leaving aircon on means stationary coolant never goes above 90c.

With these other cooling system mods no matter how hard i drive coolant 95c max and oil 100c max, also if you stop car afterdriving hard, turbo out pipe (boost side) so hot stainless blue and you cant touch (yes i did ouch)
after intercooler (throttle body side) stone cold.

Front mount a lot of money and looks ace, does job, but for 1200 pounds in retrospect would have spent money on AP Brakes. Yes i know have, not fitted yet hope this weekend. If your not going BIG power i would spend money on brakes and suspension you will go faster and have more control,
if you go front mount factor in cooling system mods and remap nearer 2000 pounds when id done for 10 bhp!!

Hope this helps feel free to ask me anything else.

Thanks Jase.

Mo

Elmo,

you really need begin by asking yourself a couple of questions:-

• What is your desired power level
• Under what conditions is the vehicle used

If it's predominently for road use with the car being run at moderate boost levels then a top mounted intercooler really should suffice and the best of the bunch are as found on the newage Imprezas. You should be able to source one of these for around £200.

If on the other hand you are looking to sustain very high boost levels and/or conduct a lot of your driving on track then you should be looking at the benefits of a front mount.

SPIKE LIKE MIKE

Hi matey,
asked this question myself before my last visit to WRC,unless u want to hit 400 or over i wouldnt bother,
with the aps tmic,ind kit,3.5 zorst u shoult hit the 360-370 comfortably and a bit more,
im currently running 352bhp with the above but 2.5" zorst,if I upped the to 3" 0r 3.5" zorst id hit the 360-370 with ease ,
If u are thinking of going down this line drop WRC a line,they are more tan happy to discuss and explain what can be done and at what costs,

goodluk

mike

j900ase

365bhp max with standered uk turbo ( i have APS front mount / blow off valve 3.5" exhaust Injen cold intake, WRC remap), dont mean to be pedantict but so many bull**** figures out there.

stablercarserv

The front mount has to be the way to go if you are going to drive your car hard and you have done a few mods to up the power. I have not seen a top mount yet that can compete with a good front mount.

jasonius

iTrader: (1)

Care to expand..?

flat4_ire

ehh Andy F's preeeettty quick type r has tmic man

Swen6

It's pretty pricey but Pace now produce a new top mount intercooler and charge cooler in one, it is stated to be better than the front mount, as mentioned it reduces lag, and also there is a claim that with the FM the air is cooled as it travels over the engine making it slightly less effective. with the TM it is more direct, less chance of the air cooling.
If not to be correct then sorry.

http://paceproducts.co.uk/php/produc.../subaruimpreza

mrjud

very true

banny sti

iTrader: (68)

Andy F now runs a fmic

elmo505

cheers peeps
im kinda new to the scooby scene ive only owned my scooby for a month (so still standard for now) think ill stay away from the fmic for a while at least till ive hiked the power up a bit just thought they looked pretty smart and if it had seriose benefits then i was gonna invest in one but so many of you say get brakes and suspension so i think ill be going down that rout b4. need a nice exhaust first for the first mod, i crave the sound of that flat 4 burble

mrjud

i'm sure i have seen this before.

then someone said that at speeds of over 110mph (which i never do) the tmic becomes less efficiant as the aeroedynamics of the front of the car actually start to force air over the scoop rather than into it.
If and its a big if this is true then surely the fmic is better as thats getting pounded with air all the time.
also if tmic were better wouldn't companys like rover (with all there overheating problems) start mounting radiators to the top of the engine to keep it cooler

New_scooby_04

iTrader: (4)

It seems that the TMIC is efficient for the lower speed stuff and the kind of acceleration that we tend to do on the road: i.e. short bursts and the FMIC is more suited to high speed work i.e. above 100mph, or conditions where the engine is pretty much constantly under heavy load: the track, high speed runs etc... Apparently the FMIC needs about 40mph before it starts to cool efficiently.

NS04

Mo

I'd like to see these theories of reduced airflow substantiated. I see it brought up on this bbs time and time again and I assume it always comes from what someone else has read somewhere else iyswim

I know Simon Lines at some point watched inlet temps soar but this was at speeds well over 150mph. Now I've completed thousands of miles on the continent over the years and I regularly sit at 120-130mph and see nothing to make me worry other than the petrol gauge ofcourse all this in a UK MY94 with crappy TMIC.

SPIKE LIKE MIKE

i hear what your saying ,
was at a rr last week at WRC one of our guys got 361bhp and 350 something torque with the 3" zorst and the above mods ,

cheers

mike

danwrx1980

i reckon that the techs at subaru would put FMICs in cars if they were really as good as anyone says, and i've also heard that prodrive have gone back to TMICs, but if you look on the newage cars they are slightly more angled and a fair whack bigger.
i think instead of a FMIC i would spend my money on getting the one i've got to work better, ie put a STI big scoop on and maybe use an air splitter to make sure the whole intercooler is receiving air.
after all the guys at subaru put it on the top for a reason IMO, and they know a lot more about cars and performance than i do!!!

Moley

iTrader: (9)

j900ase - do you have a link or number where i could get one of those Zero Sports racing thermostats from

Cheers

Gary

harvey

iTrader: (48)

Elmo : I will try to answer your original question.
The O/E top mount is a compromise and has become a design feature of the marque.
The purpose of the intercooler is to reduce the charge temperature from the compressed air from the turbocharger/compressor. In view of its purpose, locating it above a hot engine with a scoop in a low pressure area must be viewed as a compromise. Tape some bits of wool on your bonnet and scoop and find out for yourself what happens with the air flow.
If you fit a temperature guage and sender in the air flow at the throttlebody, even on a standard car, you will be shocked at the charge temperatures when the engine is working hard. Once the power ouput is increased and boost probably increased there are further increases in charge temperatures. This is a bad thing.
You MAY get away with a steady 120-130 mph in Germany for prolonged periods, on a standard car but it is foolhardy and to see why all you need do is fit a guage from Nomad Racing or elsewhere.
With tuning, at some point, unless restraint is used (IMHO it is well below 350bhp although every car varies) you need to reduce charge temperatures and add safety. (hot charge temps result in DET)
The FMIC per se does not create power but the lower charge temp result in more power produced, just as that would happen if the top mount was producing that cold air. With a reliable cold air supply you can also map closer to the edge, hence more power with safety.
Anything you can do to reduce charge temperatures, even on a top mount, has to be a good thing. There are a number of things you can do but just as with putting on an "uprated" top mount, you are making the best of a compromise situation.
My experience of various aftermarket top mounts has been disappointing and in my opinion it is not a cost effective solution and it is only a partial solution, even in the best case senario.
From my experience with FMICs I also know there is a big difference between those that perform well and those at the bottom end of the market.
Manner of installation can also influence results.

Now if anybody wants to argue about this, intelligently, please do me the courteosy of investing in a TB temp guage, ambient outside temp guage, a ball of wool, sticky tape and your own detailed observations.

Andy F had a top mount on his car 15 mths ago and it was nothing like any top mount you could buy from the after market supply companies and it presented some fitting problems. I know as I was involved in fitting it. Its purpose at the time was to make the car safe over a quarter mile. ie 10 seconds. Charge temps were rising at an alarming rate at the end of the quarter. At no time was the car used for top speed running which obviously takes much longer and it would have been foolish to do so.
This year a FMIC was fitted to cater for top speed running which the top mount could not handle.

The "experts" will tell you that FMICs add lag. Maybe they have been unlucky in specifying duff kit. There may be marginally more lag with a well designed FMIC but it is not signifigant in my experience. The turbo, mapping and other factors can have a greater effect.

I hope this helps to dispell some Scooby Myths.

marklemac

I've got the Zerosports thermostat (David Hendy supplied) fitted to my STI and according to the SECS display, the car now runs between 76degrees>around 86.

When stuck in traffic it does goes up slowly and maxes out at 97 degrees, never higher, as the fan is triggered at 97 degrees.

Drive off, and the temps then come back down.

Mo

Harvey,

I'm really not dismissing a FMIC for many applications they are worth there weight in gold however I don't see it as a neccesity as some people here believe it is. I stand by what I said earlier and that is that if someone is after a mildy tuned Impreza for the road then they may not need the expense of a FMIC.

I covered many high speed miles in my old UK car and yes I monitored TB temps and EGTs and never saw anything that made me back off....other than traffic. At 90k, when I purchased the car, I raised the boost with fueling to suit and ran the car with the standard TMIC for the next 50k (and a MY00 TMIC for a further 30k) with no problems on the road, track use however it couldn't cope and would only last a couple of laps before I had to backoff as temps were soaring.

Anyone know what intercooler Andy runs on his WRX?

harvey

iTrader: (48)

Hi Mo: I am not arguing with you. Very much down to what you feel you need and personal choice. I put off my fist FMIC for ages but as soon as I checked the actual temperatures the decision was made.
As you have measured the temperatures, I think you will agree that a top mount is a bit of a compromise. I get about 2 deg C over ambient up to 4,500 rpm in the cruise from a FMIC, something no top mount has been able to get near, by a large margin, so far.

Moley

iTrader: (9)

I have got a Hybrid FMIC on my car and it is superb!!!!

Don't believe everything you hear about lag, it really isn't that bad at all, actually makes the car more driveable around town!!!

(ps....my car is only 270bhp at the most)

GC8

Harvey; have you experimented with a 'charge-cooler' similar to that used in the early Legacys?


Simon

harvey

iTrader: (48)

Yes. The results were contrary to expectations and very disappointing.

GC8

Bummer..........

Mo

Harvey I realise you are not arguing and I believe we all agree, Subaru and Prodrive included, that the TMIC is a compromise. It' s only there as OE placement for convenience and minimal pipework something road going turbocharged vehicles require for minimal lag.

Threads like these when someone asks if a product or service with a relatively large financial outlay is worth it mostly get everyman and his dog coming on and singing it's praises even if they weren't that satisfied with it. Let's face it how many people have purchased a product after reading how great it was only to be left disapointed and come on here and let everyone know? Not many I bet. I'm not saying this is the case with front mounts but it's only fair for the thread starter to get the full picture so they can go onto make their own mind up.

If it were my money................

..................I'd go for the front mount because you know it won't be long before that built engine and a garrett calls out