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Old 08 February 2008, 04:44 PM
  #31  
Tidgy
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Originally Posted by GONZO01
the problem as i've had it explained to me, is an incompatability between the front mount and the maf sensor, which causes the ecu to delay for a split second before deciding what to do, if you remove the incompatability then you wont get the issue, simple as.


So Tidgy am I right in saying (as your quote above) if I get a Simtek remap to go with the FMIC hence the MAF being removed lag should be less

yeap, the simtek does away with the maf sensor, also so does autronics (whats on mine) motech and several others
Old 08 February 2008, 06:16 PM
  #32  
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Originally Posted by fireblade37
One thing i did really notice from changing to a frontmount was on hot sunny days it didn't no way near affect the performance of the car in comparison to the topmount. But i do a lot of sitting at traffic lights, holiday traffic etc in the summer months, so the frontmount suited me. I always thought fitting a front mount was for safety NOT performance.
Maybe you should tell that to Andy Forrest who in this thread: https://www.scoobynet.com/general-te...se-please.html

says:

"I still use an Sti TMIC on my 2.5 Sti RA with a 321T running over 450bhp. That includes track use, 20 laps of knockhill the other weekend and it was fine."

and also says:

"In my opinion, a front mount is a backward step on a newage car if it is already fitted with an Sti 8 TMIC and aiming for circa 350bhp. It may even make it slower despite possibly showing a few more bhp under steady load on the rollers."
Old 08 February 2008, 08:36 PM
  #33  
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Originally Posted by lunar tick
Maybe you should tell that to Andy Forrest who in this thread: https://www.scoobynet.com/general-te...se-please.html

says:

"I still use an Sti TMIC on my 2.5 Sti RA with a 321T running over 450bhp. That includes track use, 20 laps of knockhill the other weekend and it was fine."

and also says:

"In my opinion, a front mount is a backward step on a newage car if it is already fitted with an Sti 8 TMIC and aiming for circa 350bhp. It may even make it slower despite possibly showing a few more bhp under steady load on the rollers."
I don't track the car i commute to and from work and sit in heavy traffic on most days.
My00 classic not a newage with a sti topmount
Old 08 February 2008, 08:49 PM
  #34  
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Sorry Fireblade37 does this mean you have a classic with STI8 topmount if so how do you find it I.E throttle response spool time etc
Old 08 February 2008, 11:45 PM
  #35  
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Originally Posted by GONZO01
Sorry Fireblade37 does this mean you have a classic with STI8 topmount if so how do you find it I.E throttle response spool time etc

I think he means he has a classic with an FMIC and has come from a Hyperflow TMIC, not from an STi 8 top mount mate.

A good FMIC will be still be better than a TMIC when it comes to keeping charge temps down esp when stationary (although as pointed out, an STI 8 TMIC is MORE than adequate at this, once moving). Also the FMIC is the safest solution if you tend to do lots of high speed runs.

I definately think the move to an FMIC is a better/more economical step for classics than new ages though!

Ns04
Old 09 February 2008, 09:59 AM
  #36  
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Originally Posted by New_scooby_04
I think he means he has a classic with an FMIC and has come from a Hyperflow TMIC, not from an STi 8 top mount mate.

A good FMIC will be still be better than a TMIC when it comes to keeping charge temps down esp when stationary (although as pointed out, an STI 8 TMIC is MORE than adequate at this, once moving). Also the FMIC is the safest solution if you tend to do lots of high speed runs.

I definately think the move to an FMIC is a better/more economical step for classics than new ages though!

Ns04
Old 09 February 2008, 10:09 AM
  #37  
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Originally Posted by New_scooby_04
Also the FMIC is the safest solution if you tend to do lots of high speed runs.
Depends what you term high speed ? I have tested charge temps up to 150mph on a 450bhp Sti7 running with the std bonnet scoop, they were still well under control, certainly not enough rise to warrant any ignition retard being applied from the ECU.
What happens after 150mph on the new age cars I don't know.

FWIW I still use a (rather large) TMIC on my classic race car but I fitted a 20mm taller scoop to cope with slightly higher speeds

Old 09 February 2008, 10:20 AM
  #38  
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thats just silly
Old 09 February 2008, 10:49 AM
  #39  
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FWIW I still use a (rather large) TMIC on my classic race car but I fitted a 20mm taller scoop to cope with slightly higher speeds


Andy, do you use the classic for a weekly shop to asda, getting to work, sitting around in traffic etc?
This was the reason why i fitted a front mount. And in my humble opinion, i should have done it years ago, it works for me. And without LAG.

cheers
Old 09 February 2008, 11:01 AM
  #40  
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Originally Posted by Andy.F
Depends what you term high speed ? I have tested charge temps up to 150mph on a 450bhp Sti7 running with the std bonnet scoop, they were still well under control, certainly not enough rise to warrant any ignition retard being applied from the ECU.
What happens after 150mph on the new age cars I don't know.

FWIW I still use a (rather large) TMIC on my classic race car but I fitted a 20mm taller scoop to cope with slightly higher speeds

LOL Andy, if you go any taller than an STi scoop, technically it becomes a tunnel!!

I prefer the more understated "bling" of an FMIC.

If it ruins my car's drivability, I owe you a drink.....only a coke mind, as although I live in London, in terms of my wallet, I'm a Scotsman!
Old 09 February 2008, 11:05 AM
  #41  
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Originally Posted by fireblade37
Andy, do you use the classic for a weekly shop to asda, getting to work, sitting around in traffic etc?
I don't use the classic but I do use the 450bhp one for that sort of town driving.

Do you use full power whilst at Asda or sitting at the traffic lights

Under-bonnet heat management can virtually eradicate heat soak when stationary. I normally find my car is moving prior to being able to use full power anyway.

You do have more lag, whether or not you find it an issue is a personal thing.
You also have throttle response issues, regardless of ecu. You effectively have a pressure buffer between the turbo and the engine, this takes time to fill and empty, giving a sort of 'elastic band' feel to the throttle input.

As I say, some live with it quite happily, others it bugs the hell out of.

Last edited by Andy.F; 09 February 2008 at 11:07 AM.
Old 09 February 2008, 01:05 PM
  #42  
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Originally Posted by Andy.F
Depends what you term high speed ? I have tested charge temps up to 150mph on a 450bhp Sti7 running with the std bonnet scoop, they were still well under control, certainly not enough rise to warrant any ignition retard being applied from the ECU.
What happens after 150mph on the new age cars I don't know.

FWIW I still use a (rather large) TMIC on my classic race car but I fitted a 20mm taller scoop to cope with slightly higher speeds

What TMIC is that Andy its huge
Old 09 February 2008, 07:23 PM
  #43  
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Originally Posted by Andy.F
You also have throttle response issues, regardless of ecu. You effectively have a pressure buffer between the turbo and the engine, this takes time to fill and empty, giving a sort of 'elastic band' feel to the throttle input.

As I say, some live with it quite happily, others it bugs the hell out of.
Like me which I why I went back to a TMIC. Maybe my punishment for having driven a car running throttle bodies for 3 years - hard to forget that 'instant response' feeling

(sorry edited - should have read: I went back to a TMIC! )

Last edited by lunar tick; 09 February 2008 at 08:57 PM.
Old 10 February 2008, 08:15 PM
  #44  
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I have very little experience of driving New Age cars before and after fitting an FMIC, certainly after the FMIC has been mapped but I do have considerable experience of FMICs and TMICs on Classics. (I am looking for a New Age WRX etc 01-05)
Firstly, if the volume of air in the system is increased then it stands to reason there must be an increase in lag or delay in throttle response with an FMIC replacing a TMIC. However, if you calculate the air consumption of a 2 litre engine per second, at say 3,500 rpm (or 2.5 litre) and compare that to the volume of air difference between the original TMIC system and the replacement FMIC and system pipework you will see it is only a small difference as a percentage of air consumption per second so the difference in response should also be small, all other things being equal.

I read a very interesting article in Autospeed and here is a quote:

Some people believe that if they fit a very big intercooler with large ducts, the volume of charge air within it will unduly slow throttle response. Their concern is unjustified however - throttle response problems (for example, turbo lag) are largely the result of other factors within the forced induction system, not the volume of air within it.
I subscribe to that view and it is bourne out by my experience on Classics.

I also read the Jap Performance article on top mount -v- front mount, very carefully, more than once and while I accept and understand that Scooby Clinic wanted to promote their own FMICs, I do think their conclusions were reasonable and in line with my own.

Andrew : When you changed from FMIC (which I was responsible for fitting along with turbo and probably injectors???) what else was changed at the same time?
How do you know that the mapping of the TMIC or some other factor is not responsible for the reduction in lag.
I know you were one of the few people monitoring charge temperatures but some people do enter the debate without having that facility.

Because of flagrant claims about the ability of the New Age TMIC on the Classics I embarked on this exercise purely to broaden my knowledge. The STi 3 Wagon (335 bhp) with both ambient and air charge monitoring could exceed 70C ACT from normal running temp, in a full power acceleration run from 0-100 mph on the O/E TMIC. I then tried an STi7 scoop. Thanks David Reid, DRMotorsport. This was a small improvement. I then tried an STi 8 scoop and this showed a much more noticable improvement with 70C exceeded, passing 120 mph. I then fitted an STi 8 TMIC, a job I will not be repeating because it is time consuming, expensive and not worth the effort compared to an FMIC. When fitting the STi 8 TMIC it is important to fit the under tray and STi 8 scoop.
With the O/E STi3 scoop results were not acceptable, there was an improvement with the STi 7 scoop but it was only after the STi 8 scoop was fitted that the results were acceptable although not as good as from the FMIC on a much more powerful WRX Wagon (422 bhp) with Hybrid FMIC.

I don't doubt that the recent New Age Subarus can run a TMIC satisfactorily up to 400 bhp but after that I would want the comfort of an air charge temperature guage because at some point the TMIC will not cope.

What is acceptable on a 1/4 mile car or short sprint competition car has limitted bearing on a road car used as a daily driver. You cannot get out and pack ice on the TMIC every so often or give the core a blast of freezing gas.

Last edited by harvey; 10 February 2008 at 08:18 PM.
Old 10 February 2008, 08:39 PM
  #45  
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Hi Harvey. If you remember we kept the same turbo and injectors when you fitted my FMIC. When I swapped back to TMIC, the injectors were uprated and the bigger turbo installed. Headers were left the same. Paul Blamire mapped the car at this point, but I'm not sure previous bad mapping explained the in-gear lag I was getting with FMIC because both AndyF and Bob Rawle were unable to map this out and of course, they're both excellent mappers. Of course I'm sure the bigger 321 turbo helps reduce lag, but then I did compare my car with FMIC and VF35 back to back with a similar spec remapped car running VF35 and TMIC and found the latter much crisper on the throttle response.

As I said elsewhere on here, I'm probably quite sensitive to this because I've spent quite a bit of time driving a car with throttle bodies (read instant response!) - others may not find it a problem. Cheers, Andrew.

PS - I'll be calling you soon for big order of NF
Old 10 February 2008, 10:29 PM
  #46  
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So harvey and Lunar tick which in your opions would you recommend TMIC or FMIC, and if TMIC would you suggest a STI8 on my classic or if FMIC which one to cope with up to 400 bhp. Also Harvey as you are on line what would you recommend Header/Manifold wise you can do for me to achive 400bhp and that can cope with that power Port and wrap my original headers or buy new ones?
Old 10 February 2008, 10:43 PM
  #47  
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Regards the FMIC lag issue, lets put some numbers on it.

From a quick calculation (sizes from memory so just approx) I calculate that a 2000 cc engine running at say 3500rpm consumes 52 ltrs of free air per second, assuming a VE of 90%.

A typical TMIC consists of
Pipework 200mm @ 50mm bore = 0.4 ltrs
Cooler core 400x170x60 (x40% assumed occupied by charge air) = 1.6 ltrs
End tanks 400x60x30x2 = 1.4 ltrs
TMIC total volume 3.4 ltrs

FMIC
Pipework, 3 mtrs? @70mm (some at 50mm, some at 75mm, average 70mm)
3000 @ 70mmbore = 11.5 ltrs
Core 600x300x75 (x40% occupancy) = 5.4 ltrs
End tanks 300 x 75 x 75 x2 = 3.4 ltrs
FMIC total volume = 20.3 ltrs

Additional volume within FMIC v TMIC system 20.3 - 3.4 = 16.9 ltrs

If our engine consumes at 52 ltrs/sec then 16.9 ltrs will take an additional 0.32 secs to pressurise.

0.32 secs doesn't sound like much but on a car that does 0-60 in say 4.6 secs, 2nd gear may last 2 seconds, 0.32seconds is a 16% time delay.

Add all those 0.32 secs together on each gearshift and you start to understand how the quickest 1/4 mile 2.0 std internals cars (classics) all run TMIC's.

I'm referring above to 2.0 classic Impreza's on std internals in the 340-390bhp range, running mid 11's on the 1/4 mile at 114-119mph, I know of 4 of them all on TMIC's. Its not the power thats making these cars so fast, its the instant response

Andrew (lunar tick) how are your charge temperatures on the TMIC now with over 400bhp ? I assume Paul was happy that they were safe during mapping ?

Last edited by Andy.F; 10 February 2008 at 10:48 PM.
Old 10 February 2008, 11:03 PM
  #48  
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Evening Andy so you would recommend the STI8 TMIC intercooler on a classic aiming for 400bhp and are they that much hassle to fit also am I right in assuming I would need a STI8 Bonnet scoop aswell? or do I fit the one you have on yours what is that it is massive.
Old 10 February 2008, 11:05 PM
  #49  
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Ihad a large engine failure recently which was blamed entirely on the running of a TMIC! STI8 ic with built 2.0 MD321t
Old 10 February 2008, 11:09 PM
  #50  
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Strange all these Type 20 and 25's manage fine with a similar spec ?
Old 10 February 2008, 11:10 PM
  #51  
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Your maths are a bit out. Even if I accept your .32 sec delay per gear change the on a 0-60 mph sprint in 4.6 secs. the increase in time is nearer 7% and where two gear changes are required, 14%.

However a .32 sec delay on a 2 litre road Subaru is not really something to get excited about. For drag race, fair enough but drag cars are not ideal every day road cars.

Gonzoo1 : 2 litre M/Y 2000. What turbo and relevant mods including turbo, injectors and what do you want to do with it?
Old 10 February 2008, 11:12 PM
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Originally Posted by Andy.F
Strange all these Type 20 and 25's manage fine with a similar spec ?

indeed
Old 10 February 2008, 11:16 PM
  #53  
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The 11 second cars I referred to are road cars, they just go racing at weekends with them.
Old 10 February 2008, 11:18 PM
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Am having a Hybrid FMIC fitted to my car tomorrow, funnily enough bought it from a guy on this very thread who had gone the other way
Old 10 February 2008, 11:22 PM
  #55  
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One mans meat as they say
Old 10 February 2008, 11:22 PM
  #56  
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Originally Posted by cookstar
Ihad a large engine failure recently which was blamed entirely on the running of a TMIC! STI8 ic with built 2.0 MD321t

how could they narrow it down to a TMIC ???
Old 10 February 2008, 11:40 PM
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beats me, i forget the technicall reasons that were told to me at the time, after much debate it was blamed on the tmic
Old 10 February 2008, 11:59 PM
  #58  
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Good to see some figures on this (thanks Andy). On cuising, charge intake temp is within 1-5C of ambient. Under hard sustained throttle, temperature rises up to 20C above ambient (which I admit is more than with a FMIC where increases were within 10C of ambient). However, Paul seemed more than happy when mapping.

Funnily enough, in previous posts on this topic, I have stated that when I had the FMIC fitted, I felt as though it took between a quarter and a half a second between depressing the throttle (while on boost) and the car responding. 0.3 seconds per gear change doesn't sound much, but say going from 2nd-5th, that's nearly a second of 'dead' non-accelerating time. I concur that on the open road through the gears, the car seems quicker with a TMIC despite the fact it may have lost a few bhp at peak power that I would have had with a FMIC.
Old 11 February 2008, 12:00 AM
  #59  
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.

Gonzoo1 : 2 litre M/Y 2000. What turbo and relevant mods including turbo, injectors and what do you want to do with it?[/QUOTE]

Evening Harvey currently running around 310 bhp want to get to around 400bhp if possible but really just want a quick road car from point to point.
Old 11 February 2008, 09:58 AM
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[quote=lunar tick;7643481], I felt as though it took between a quarter and a half a second between depressing the throttle (while on boost) and the car responding. 0.3 seconds per gear change doesn't sound much, but say going from 2nd-5th, that's nearly a second of 'dead' non-accelerating time.

A blink of an eyelid It might matter to some, but as a daily driver, who cares about 0.3 seconds between gear changes. Lets face it, probably 95% of subaru drivers on this forum will never/haven't track/drag there cars. My concern was ambient/charge temps and fitting the frontmout was the way forward for ME As for throttle response yes a little spongy. I presume that's where your getting the 0.3secs from. Like Andy said, some can live with it, some dont.

Last edited by fireblade37; 11 February 2008 at 02:00 PM.


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