BIG FUD

iTrader: (84)

I was running top mount on my spec c standard engine with a sc42 charge temps went through the roof as i drive very hard This is surely must be taken into consideration.

I went for a £180 front mount as i could not buy a chevron top mount even though i know these are the daddies out there.

For many people doing very rare track day's i would stick with the sti top mount as felly say's they do work,But if you are a driver and want to take it serious enough and have the fund's chevron top mount is the way forward.

Or buy a cheap front mount like me you cant loose money like i did i flipped the mannifold and lost virtually 0 boost low down.

johnfelstead

So i had to do a 50 mile run this morning, so thought i may as well log it for some info in here. The run consisted of cross country Dual Carriageways, A roads and B roads, including time through town centres with stop start traffic. The run included full throttle through the gears runs from stationary, plus full throttle 4th 5th and 6th gear accelerations from cruise.

Ambient at the start of the run was 3 degrees C, at the end of the run it had climbed to 8 degrees C. Peak boost was 1.95BAR, peak engine speed 6830rpm, peak oil temperature 86 degrees C, peak water temperature 86 degrees C (Chevron combined water radiator and oil cooler assembly). Engine is producing circa 450/470 on a 10% Meth mix road map.

Minimum Charge temperature shown was 2 degrees C, on cruise it basically would sit 1 degrees C below ambient or ambient. Max Charge temperature was 14 degrees C which was attained post sitting in traffic stop start driving followed by full throttle acceleration through the gears into 6th.

Each log image is a log for the full length of time the heated rear screen is on, which is about 15 minutes. There is an 8 degree offset in the charge temp sensor, which is why the run starts at ambient of 3 degrees yet the charge temp shows -5 degrees, it is a linear offset through it's working range, so when showing 6 degrees it is in reality 14 degrees C charge temp.

johnfelstead

Same logs with plots against Speed.

Davey96wrx

iTrader: (1)

I actually think it depends upon what model car we are talking about, all you lot are banging on about your newage things which have much better packaging to provide a good size TMIC.

But for classic owners esp pre96 owners a front mount is the only viable option and even though the newage sti tmic can be fitted to post96 cars the packaging is not as good aswell as airflow which is possibly why it's so popular on this site to go front mount rather than tmic, and £2k on an intercooler is frankly ridiculous imo.

An EQUALLY well designed core in a front mounted position with a reversed manifold and short length pipe work WILL be better, end of.

johnfelstead

You will have to spend money on rotating the inlet plenum, piping that up, buy a custom radiator to allow for short pipe runs and then you still have to buy the core material, which is where the real cost is.

Shaun

In the "real world" people will buy the most cost effective option, regardless of how technically superior a n other option is.

I sure for **** wouldn't bother rotating the manifold..... the benefits are minimal, but then I personally wouldn't spend £1800 on an intercooler for a Subaru! lol However, I would rather spend £1800 on a neat and functional TMIC for my current set-up, over a FMIC and rotating my manifold.

I'm confused now.

johnfelstead

Like i said earlier, you dont have to spend £1800 on a TMIC for most peoples use.

MattyB1983

iTrader: (51)

I'd be interested to see the results a good front mount would produce. I think Jura is able to log so will send him a PM.

jura11

iTrader: (7)

Hi Matty

I would be very happy to log,but at moment car is at the bits(2.35L build in progress) and its not possible to log




Jura

trevsjwood

iTrader: (2)

but it would still only be part of the story, both turbo's would have to be logged if an efficiency comparison on the intercoolers was being run.
Trev

johnfelstead

Went to the nurburgring this last weekend with Big Fud.

The circuits were wet so i couldn't nail it as usual on the nordsliefe, so peak speed was only 140MPH on there. Peak charge temperature was 10 degrees C.

I did two, 20 minute sessions on the GP circuit also, again the circuit was wet but not raining, just a bit foggy, but it was flat out for the whole session passing full race spec Porsche GT3's and M3 CSL's, i even lapped some of them. Peak speed on there was 121MPH, Peak charge temp was 18 degrees C.

Big Fud was running at the same time, similar engine spec and power to mine with his FMIC, his was peaking at 25 degrees C during the same sessions, but his runs were not as long due to his oil/water temps going high giving an ECU triggered end of run.

My peak oil temperature was 102 degrees C, Peak water temperature was 82 degrees C after the 20 minute flat out runs on the GP circuit. Oil ran at 88 degrees C on the nordsliefe.

BIG FUD

iTrader: (84)

This is correct also you have to have same engines ie 2.0 2.1.Also very important the sensors must be in the same position.

My sensor sits under my throttle body so is very closed to the block now if you have a top mount with the sensor at the rear above the box housing this may give a slight less reading.

Without doubt the top mount felly is running is the real deal, its exspensive but hey lads if you are racing and in competitions and want the best its never cheap.Also you get better spool as shown in his graphs, In my eyes no pipe work no cutting of ya bumper.

I run a e bay £180 front mount my syvecs unless the act goes mad high while racing will not, does not reduce timming.

In a nutshell. If you have the money and want the best this is it.Its proven to work and work it does,To me its like a 6 speed box or a md turbo or syvecs ecu,they are exspensive for a reason they are the best at what they were made for.

Tidgy

john, i think your totaly missing the point dude. your top mount is way beyond the cost of any front mount most folks will ever see let alone buy, so unless you compare directly an sti top mount with a front mount what your saying is totaly irrelevant.

Unless you try a front mount saying your top mount is better is totaly baseless.

How many race cars do you see running top mounts unless there is regulation restriction?

Pretty sure gobstopper, bannana, danny p's, vaugh's etc etc are all running front mounts (which i bet are cheaper than 2k).

johnfelstead

I am not missing any points dude.

You were telling people TMIC's get no airflow at speed so cant work. I've just proven that to be complete crap, something i proved 10 years ago on my 300BHP STi5 RA at the nurburgring, but even at 450BHP on a Blobeye the TMIC doesn't have any airflow issues.

Even a stock TMIC will work at speed because it does get good airflow, so long as it's sized to suit your power levels you dont have to go FMIC, which is all i was looking to show.

The fact mine outperforms most FMIC wasnt the main point i wanted to make, thats just aditional info.

You get the point re airflow being OK and accept that yet?

And there you go again siting a 2K intercooler. If the Gobstopper etc ran with my core materials, their FMIC's would cost more than 2K. TMIC have been used on front running TA cars.

People in Europe may find this TMIC the only option to run big power, as they have much tighter controls over how they modify their cars, with them not being allowed to use a FMIC.

Tidgy

I dont think i said no airflow, i said reduced airflow. no mater what the size of the cooler, the airflow limit is the size of scoop. where as the whole front end of the is open for a front mount.

MattyB1983

iTrader: (51)

Your top mount is obviously a fantastic bit of kit John and I'm impressed with your results above, I've also seen the threads over on 22B about it. If it was more affordable I'm certain far more cars would use it over FMIC.
However, its just too expensive for 99% of owners.

A better test would be to match a standard STI top mount against a budget front mount or better still, your top mount against a decent front mount. I'm not knocking Fuds FM but by his own admission it's just a £180 eBay cheapy. I'm sure a Hyperflow, cosworth, APS would get far better results and are priced more closely to your TM

johnfelstead

I've already explained to you that the frontal area is not the key thing to how a cooler works, look at any serious race car and they have very small inlets. What matters most is the exit path for the air, and with a FMIC you have the water radiator, air con radiator, oil cooler and then engine in the airflow exit path, which is not very efficient. This is why on the WRC cars they spent a huge amount of effort designing out those issues with exits for the top mounted FMIC. The TMIC also has restrictive exit airflow due to the gearbox, but FMIC are not better in this respect.

You will find on a lot of race cars the cooling packaging has the water radiator almost horizontal, with airflow forced through 90 degrees to pass through the core. You dont find upright coolers on any modern serious race car because it's too draggy. The cooling entry duct design on the Group C Jaguar XJR9for example is almost identical to the subaru TMIC entry, only it's mounted on the side of the car, which is an even worse place than the front in terms of airflow, due to turbulence from the wheels.

To make a cooler core work properly, you have to seal the airflow fed to it, and if you have cores behind, you have to seal the area between both cores to force air through all the cores with minimal turbulance, this is something that is easy to do on a TMIC, not easy at all on a FMIC as installed on Subaru's.

johnfelstead

I dont disagree about the costs Matty, which is why i am not trying to emphasize the performance of mine. I'm just debunking some of the nonsense with regards to the airflow through the cores, for most people a stock STi8 TMIC will more than do the job.

Andy Stevens

Interesting discussion. I like that it is backed up with some real data. Here is a quick log from today off the ESL Demo wagon, 550hp, 2.0 litre, stock location GT30 turbo, hyperflow FMIC. Ambient temp was 12 degrees C. The car had been warmed up beforehand. The sensor is located in the last pipe before the throttle plate.



There are two factors opposing ech other here. the compressor adds heat, the intercooler attempts to reduce it.

With reference to the logs you can see that the cooler on the ESL car is winning because as vehicle speed increases, airflow to the intercooler increases and charge temperature decreases.

This increases the density of the air entering the combustion chamber and in turn increases power.

Andy Stevens

In respect of having to reverse the inlet, lets do a *** packet calculation:

The runs on the FMIC of the ESL car (not reversed) are about 2m either side of the cooler.
The hardpipes are 2.5in diameter (6.35cm), so CSA is pi*r^2 = 0.0032m^2
Total volume of hardpipe is length*CSA=0.013m^3

If we look at the spool up condition, I'm going to say 4000rpm, 1 bar, 100% VE, a 2 litre engine is going to shift around 0.133m^3/s (IRO 280CFM in old money). Which is 0.066m^3 when compressed in the pipework.

Lets say that the TMIC has a zero length pipe run for simplicity. That means the extra time getting the air through the added FMIC pipework volume is 0.2 seconds.

I personally think that isn't much gain for the effort required.

Feel free to check my maths, it isn't my strong suit.

johnfelstead

0.2s is a massive amount of time when you are looking for limit handling throttle input response, makes no difference if chasing dyno figures though.

Since doing my trip to the nurburgring, the car has been remapped and fitted with a Forge Recirculating dump valve. The OEM dump valve was leaking, passing hot air back into the turbo inlet, which wouldnt have helped charge temps.

The engine has picked up a tonne of torque and power as a result, charge temps are even better now.

Andy Stevens

You probably have very much better reactions than me, but I think that 0.2s is almost lost in the noise when compared to the myriad of other factors present such as turbo and throttle dynamics.

It would be interesting to see a log of your new set up, it was a bit hard to see from your other graphs but it looked like your charge temps were increasing with vehicle speed.

andy97

iTrader: (1)

When I had a front mount IC fitted my mapper said that he was able to advance the timing an extra 3 degrees without doing anything else to the map. He equated an extra 10 bhp for each degree of advance. So fitting a front mount IC is worth a fair bit. If you then fully map to use the front mount to the max then significant power cable be achieved provided your other performance parts are decent

johnfelstead

When you have charge temps 1 degree below ambient at cruise, you would expect to see the charge temps go up a bit on a pull.

You can completely change the car dynamics by timing your throttle inputs acurately, i was getting a bit rusty so had another day with Don Palmer last year, we changed my throttle input points by 0.5s and completely changed the way the car responded.

Probably not relevent to the high street, but very relevent to limit handling.

Shaun

Andy,
Very interesting results and saves me faffing around doing it! lol

Is this on the GT2 core?

trevsjwood

iTrader: (2)

It would have been good to know if the compressor wheel outlet temps have dropped by much but at a guess and based on my experience, could be as much as 40c?
Trev

johnfelstead

I dont have any logging on that Trev, but the turbo picked up 0.25BAR just by changing the dump valve, so that tells a fair tale there! Peak torque pre the change was 490ftlb driving the turbo hard, it now has 540ftlb with the duties reduced significantly.

trevsjwood

iTrader: (2)

Thats a good result JohnI had a similar experience after replacing my dump valve, hitting just under 2bar on the first run out.I've got a thermocouple probe in the turbo-intercooler connecting pipe and it was this that flagged up things were not right, on a hard run, flat out at 1.6 bar, turbo outlet temps were soaring as much as 200c.

Trev

johnfelstead

Mine was pulling 2.2BAR LOL

Andy Stevens

I don't know that much about the Hyperflow kits Shaun, it has been on the car since StanS fitted it, probably the best part of a decade, so if GT2 is the modern stuff then I think it will be an earlier variant.

Interestingly enough running the calcs and looking at the hyperflow spec got us thinking, look at the power graph and bear in mind the boost was a constant 1.9bar on the dyno without dropping off at higher engine speeds;



Peak power, impressive though it is on that turbo, is reached very early, suggesting a flow restriction, as anecdotal evidence suggests sti3/4 heads would do better than that. Hyperflow do seem to rate their FMIC at 400kW, which we are now in excess of. But I am just guessing at this point!