New_scooby_04

iTrader: (4)

AFAIK Yes

Harvey has elaborated on this many times!

As I've said before, the only difference I've noticed is a stronger shove in the back when the boost kicks in!

I will try and get some footage of some runs as recorded by my AVCR and you'll see - an FMIC set up can be plenty responsive enough!

Ns04

Ns04

lunar tick

iTrader: (2)

Yes, you do stand to be corrected as they somewhat erroneous

Here's how the calculation should be done as explained by the master AndyF back in February.... (oh, and a third of a second can be an eternity when you're zipping up through the gears!):


ORGINAL POST BY ANDY F
"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."

New_scooby_04

iTrader: (4)

Without wanting to be argumentative, esp with Lunar who is a good egg!!

That does have to be set against the performance that can be gained by the FMIC upgrade. I got an extra 20 something bhp and 30ftlbs torque from upgrading to FMIC, I'm not sure what that translates to in qtr mile figures though! My maths aint that good!

The central point is that it must negate the loss in reponse to some extent.

Also, we're talking about road cars here, very different from a 12 second blast up the strip.....or 8 seconds in Andy's case! The delay may be a problem there, but on the road, you wouldn't notice it, and you can keep your foot planted for as long as you like and the temps will never be a problem! The law might have something to say on the issue though!

Ns04

leeroywrx

iTrader: (10)

wow i didnt realise this was such a hot topic!!!!anyway ive gone ahead and ordered a hybrid fmic this may stir people enough for another 40 posts but i think this maybe a safer option when my boost is raised.anyone any idea what bhp and torque i should see?thanks again for the replys

lunar tick

iTrader: (2)

Hi NS (another good egg ) Just lost a long reply about this so will keep this brief

You're right that there's a trade off; under hard sustained throttle and all other things being equal, a good FMIC will allow a somewhat cooler charge temperature and more power. For this reason, if my car were a trackday machine, I may well be tempted to go down that route. But actually, on the road, where gear changes are more frequent and full throttle duration is shorter, the need to get on boost after gear changing ASAP is even greater, and I found that's exactly where I noticed the benefits of crisper response. But as I have said, I'm a bit **** about throttle response - it may well be much less of a bother to others. BTW - If you're ever down this way, you're more than welcome to come and try my car for yourself to see what I mean

Maz

iTrader: (34)

An aside perhaps but I'm not keen on the idea of big scoops. Albeit scoops are synonymous with Imprezas, has anyone any idea of the drag they cause and subsequent loss of performance. I personally think after a certain speed they're just a big air brake although you obviously need them to get air to the intercooler.

Jeem

iTrader: (1)

Wouldnt know about drag and aerodynamics but do reverse mounted scoops work to let air out of the engine bay when a fmic is installed ?

ex-webby

In short.... codswallop!!!

No such thing as NO lag on a turbo charged engine. The only way you will ever get NO lag is by having a NA engine.

Driving an M3.... that is the definition of no lag or zero driveability problems at all.

Regards,
Shaun

typeRv4

Classic scoop looks great...

but after a certain speed the classic scoop doesn't work !!!

Tidgy

sorry should have said no additional lag , yep there is a delay in the rev range (low down) so just keep the revs up lol

i keep hearing figures of it takes x amount of time to pressurise etc etc, however it doesn't have to be at full pressure to let air flow through it, so all the time pressures building then theres airflow going through anyway