GimmeMore

Hi,

Whats the concensus (or your experience) on best combination of up-pipe, down-pipe & headers for an STIV engine with stock turbo? I currently have a large bore straight thru exhaust from the downpipe back. I am after a good midrange torque characteristic ... but a bit of extra top end won't get wasted

Cheers
Paul

wrrjones

if you are loo0king at headers you would be better off going for a 4-2-1 as this is better for low range and midrange.. a decat down pipe would be a good edition before the headers ....chris

Gidney&Knowlesy

Hayward & Scott do a great downpipe, upipe & manifold combination contact Ian on 01268 727256. Plenty of mid range & top end performance improvements & would also benefit further from an Ecutek remap

David_Wallis

I would go for a set of gruppe-s Headers, H&S 3" downpipe, and HKS Hiper centre and rear..

By far the best combination (and remap)

911

Dave, what(bhp/torque) if you can't remap?
I have an Sti v3 on stock ecu, just have a 3'' Magnex decat and Blitz boost controller(@ 1.31). Looking to fit Grouppe S manifold, H&S slipper up pipe (stock Scooby inside dia).
Hope for Xmas I will be given a GEMS to go with the AndyF turbo....and the 550cc inj etc etc etc.

Will the stock ecu cope with the manifold characteristics, hopefully faster spool-up etc.?
911

Adam M

would be a bit concerned on boost if the ecu is having to cope with that much more air going through the system.

Older ecus are not as good at compensating for breathing mods. On boost they run open loop so cannot self correct for the extra air flowing. This means their previous buffer of excess fuel will be eaten into to some degree and decrease your safety net before det and high egts set in.

I would certainly think about getting a mappable ecu at that stage.

GimmeMore

Without a remap (a remap requires a boat trip to the UK) is it possible to uprate the fuel reg/pump/injectors to compensate for extra airflow? Basically, will the uprated fuelling components put more fuel in on the same ECU map/timing?

I don't mind running a bit rich till the boost is brought up to match

911

That's straight at the heart of the question!
Answers please....
911

David_Wallis

Adam,

Can you expain this Ok... Erm.. so what is the MAF doing when in open loop mode?

GimmeMore

I believe that the 'open loop' bit refers to the ECU utilising a pre-programmed map rather than adjusting stuff based on sensors (which would be a closed loop) .... hence re-mapping being the normal route for coping with airflow and other mods.

I would really like to know if uprating fuelling components will provide fuelling adjustments to match airflow mods .... for example, if the fuel pressure is increased will more fuel be delivered by ECU control with a standard ECU controlled map? It should as the timing has NOT changed thus the higher pressure should deliver more fuel ... this is my ASSUMPTION and I would like those in the know to comment .............

Cheers
Paul

Andy.F

Paul, you are correct

It is quite possible to get the top end fueling good without a remap using the methods you list although it normally means you run rich midrange which reduces torque a bit.
The difficulty comes ensuring that the ignition advance is appropriate at the higher airflow, especially on an import originally designed for higher octane fuel.
The way around the timing is to increase the octane you are running but there comes a point that you are cheaper remapping than continually tipping in octane additives.
FWIW, a few years ago I had my RA in to the 11 sec 1/4's and 360+bhp on the std ECU using these methods prior to fitting an aftermarket ECU

Andy

GimmeMore

Ta Andy.F. That's what I thought - my problem is that a remap requires a visit to the UK hence adding about 500 quid to any remap exercise with no opportunity to tweak if there is a problem, so I would like to uprate in a way that does not require a remap at every step ... eventually when I am done with adding stuff I may well go for a remap to max out the performance whilst utilising uprated fuelling components .... and for the mileage I do (the scoob is my toy ) octane booster to 100 RON works out at about 150 quid or so a year. For now though as long as I can 'control' det to a certain extent in this manner then I will be happy.

Andy, can you suggest appropriate components for what I is after? I have knocklink, boost gauge & A/F meter and a dawes. So far so good ... boost is 18psi & all readings are safe.

A new gearbox is also on my list and that'll come before the 'full monty' remap methinks ....