So your saying any VF series turbo has Lbs p/m volumetric flow to be used with a FMIC and be mapped lag free?

if you wanna work out the exact physicis of it then yes it does add lag, however, its so little that you wont notice as your driving if the car is setup well.

I disagree.

And there ends my input to this thread.

Put your theory to the man who mapped your car or any of the other top mappers in the country.
It's a topic that has been covered many times on here with the likes of JGM making comment.

Either your car wasn't setup that good or the original map it had was pants.

For what you are looking for either vf34, 35.
Probably want 550 injectors though
Stick with TMIC no need for a FMIC unless going with a bigger turbo for anywhere around 400bhp.

lot of debate here, defoo going with vf34/35 thought my 440s would be ok for 320-350??
weres best to get tmic from does it have to be sti newage?

300+ is the mark, aka the point where you ditch the standard td04.

not sure why folks keep going back to 400 as a point to do it, by that time its a major limit, not just a thing to be careful of

speak to the top tuners/mappers and you'll find out what the crack is, there have been various test about it, harvey's done alot of testing on lag, inlet temps etc etc

as soon as you ditch a TD04 you want to go front mount.

tidgy - - ok mate sent a couple of pms out see what they say.

:thumb:

440's will pretty much be at max at circa 350bhp. You could add a adjustable fpr to help.

yeah they are near as damit maxed, injectors are on the list as well as the inlet pipe to change (still on standard one of those as well lol)

:lol1: you literally spent the last two hours hunting the Internet for somewhere it said front mounts make a laggy car :lol1:

Fella, seriously, speak to Bob about how much lag a front mount will cause.
He will tell you that they will increase lag but a well setup car with good mapping will bring it to a level where it's not noticed.

I spent no time at all as it goes... this was on file. I copied and pasted the link.

With all due respect point your finger elsewhere mate... (I couldn't really give a sh1t about your rose tinted opinions...)

Simple fact is, there are many tuners and mappers who are setting peoples car up with LAG.... Do a poll... ask the masses, personally i dont care...

Lag does exist, people have it, I didn't invent lag, nor do i have lag... (not alot!) my car is set up fine i have no questions to ask of anyone.


The guy on here wanted simple facts.

Fact is front mount is the wrong thing for his set up.

:hjtwofing

You obviously have your own opinion on things and nothing I say will change that but if nothing else, speak to someone who tunes imprezas before getting on your high horse. People like Bob, Paul Blamir, Harvey etc etc etc.
We are not saying lag doesn't exist because we all know it does regardless of setup, turbo, mapper or anything else. We all have a certain amount of lag and the biggest factor is turbo size.
Maybe a front mount is the wrong setup for the OP but lag is not the reason for it being the wrong thing. You are being very narrow minded if you think this and are ignoring the countless posts from experienced tuners.
You didn't want a front mount, fair enough, many don't but don't blame added lag for changing to a top mount because a car with a good FMIC mapped properly you'd not of noticed any difference.

Good day to you sir :thumb:

Agree with Matty. In comparison to the overall volume of air a turbo pushes the extra induction length of a fmic shouldn't create a huge amount of lag. On a properly set up car with carefully chosen parts there is no lag issue with a fmic. You will gain power and have a margin of safety on intake temps.:thumb:

My personal input on this subject is the following.

My 2002 STi on the STi TMIC max out at 425bhp on the MD321T. Wasn't helped by the clutch going on the rollers at the time. Condiction of the TMIC wasn't that bad as it got regular cleaned out with a air line etc.

However I took advise from JGM and went FMIC.

With a few choice tweaks on the map from TMIC to FMIC you will notice very little if any lag at all (depending on your set up....remember this is my personal input) .

For me I wish I had gone FMIC sooner. But personally I'd stick with a TMIC until wanting over 350+ .


Steve

"On a properly set up car with carefully chosen parts there is no lag issue with a fmic" That's the entire point of this thread...

The guy wants advice on turbo's and FM's.... and lag.... it is not an opinion to say when i say a generic turbo and the wrong IC will result in lag... just simple fact.

Many people on this forum have lag, just because you say "set up properly it wont be laggy" doesn't mean that people don't actually have it... do a search... common problem

This isnt my problem, i didn't map anyone car, nor did i fit parts to anyone car.... I dont have a lag issue.. and my set up has nothing to do with this guy who wants advice. But telling him "just get a FM... it'll be OK" is bad advice, end of story.

Not to mention the dozen or so reasons other than a FM why you might get lag....

Offer a broad fact based set advice or none at all..

You've lost me, where are you actually going with your posts ?
Nobody has told the OP to "get a front mount, it'll be ok"

mapper says go with fmic so think im gonna go that way.
cheers for the info chaps, still a bit of debate which way to go i see lol

the truth is actually this -
almost every single engine will vary in some way in comparison to another. from poorly cut head to manifold gaskets, or indeed just head to manifold positioning, worn turbos, an imblance in cylinder combustion pressures, to driving technique, poorly mapped ecu, or poorly matched modifications, spark plugs not providing optimum performance, worn clutch/gearbox, or indeed the choice of RR figures used to interperate your power/spool characteristics - the list of variables is endless.
without even considering the end users interpretation of actual lag!
some say a fmic, some say newage sti - what can you draw from that? each has had different experiences - so as said above make your choice and pay your money and see what happens.

there is no replacement for actual physical testing, and on your engine! personally id say a good top mount would be ok, but then again i dont know how or where you drive, conditions ect so its just a guess.
good luck :)

420 bhp - 383 lb/ft type r with a md321h and sti 8 tmic

You are talking crap i am afraid. I've spent thousands of miles on tracks at speeds over 150MPH with a TMIC with the charge temps monitored, I've helped run front running Time Attack cars with TMIC's, the first two cars in this years 22B.COM sprint series class 2 for modified and track cars (you know, where you have to queue 10 minutes heat soaking before nailing the car) ran TMIC's, My own with aprox 460BHP/490lbft.

But John you are not running OEM TMIC atthis power;),if you will tell OP how much cost yours Chevron TMIC,he will have for this STi TMIC or Hybrid FMIC plus VF turbo and still he will have spare money on other bits




Jura

how is heat soak a problem? when does this happen?

i keep reading about guys hitting the continent at a blast then traffic where temps rise, but in traffic you wont be using boost, so why would an in-effienciency in producing boost pressure affect engine response, when your in an off-boost driving scenario?

I dont recall Subaru making a FMIC equipped Impreza, so the fact my TMIC isnt stock doesn't mater.

Sure mine is expensive, but i didnt have to go chopping the car up to fit it or pay anyone hours of labour to fit it, which saves some cost there. There is also a cheaper version available with a lower cost core material that works extremely well. Even the stock newage STi TMIC is pretty good, certainly up to the job the OP needs.

The car that won the S2 class at the 22B sprint series ran a stock TMIC until the last round, he fitted a Chevron TMIC when he installed the Twin Scroll Turbo i did the development work with all year.

People are fitting FMIC's when it's not needed, and in many cases compromising the cars peformance, not just in terms of lag, but you are sticking weight up front, which is the last thing an Impreza needs to handle well.

What reasons are there to not go front mount other than the weight issue detailed above ?
We already know that lag isn't an issue as already covered in this thread.

Cost of installing, you have to cut up the shell for the pipe runs, remove the bumper crash protection beam, cut up your bumper, heat soak issues into the pipework, reduced eficiency of your water radiator, it looks a mess under the bonnet, common to blow hoses off, it looks naff with IC cores that dont fill the apatures properly, more suseptable to stone and crash damage.

And lag is an issue. A rolling road plot will not show this up as a full throttle pull from low rpm is quite a different proposition to thrashing through the gears and demanding throttle response. Rotated throttle body plenums with short pipe run FMIC have less of an issue in this repect, but most people dont have that.

Well I would rather all the above than pay £1800 for a chevron tmic and im sure that goes for the majority on here!