Hi,
Would a remap make the throttle response more instant?
My previous car was a 205 gti and you could play with the throttle mid bend whereas the turbo is more like on-off which I am not very happy with.
The car is a 2.5 WRX.
Also what modifications (e.g. sports cat and what brand) would I need to get more torque at lower rpm? I don't really want to invest in a 3" exhaust as my 2.5" Genome backbox would then be redundant (unless I find a buyer for it).
What does the prodrive kit consist of? The car being a German spec one the warranty will be void even if I fit the PPP so I am looking at other (safe) options.
I am not interested in power figures only, I need something with more grunt at lower end but most of all reliable.
Cheers

 

Derestricting the exhaust would give faster turbo spool up which can be helped by a map. However, maps usually give much greater slugs of torque and the precision can be lost, careful work on the part throttle boost can help this. However, you have a long exhaust manifold even though your turbo is small and your engine relatively large, so it will always have disappointing throttle response compared to NA.

Most people whose first fast car has been a Scooby won't understand what you mean about a really good NA engine's throttle response, so you may get some neanderthals just telling you how to make it go faster

I would say that the 4G63 has a much better throttle response for a given turbo:engine size, but it has a much shorter exhaust manifold and a twin scroll turbo.

E46 M3 was too sensitive even in the less sensitive non-sport mode, the bumps meaning you couldn't hold a steady throttle mid-bend!

 

Excuse my ignorance but what is a 4G63?
The 205 was similar in the sense that you describe to the M3!
Do you drive a subaru now and how does it compare with the M3?
My mate has a E46 M3 which is great to drive.
Lol at the neaderthals, I couldn't agree more!

 

Toyota engine, prob a celica gt4

 

Would a JDM twin scroll turbo fit (and would the difference be worth it)?

 

The twin scroll is allot more responsive thats for sure!! As you have a 2.5 i dont think the twin scroll is suited to that engine... for the hastle involved just buy a JDM twin scroll. A better option that the UK cars anyway (see recient thread.. LOL )

 

The throttle will feel quite different to your older car experience what with your 2.5 scoob being 'drive by wire' throttle. Some people have had issues with less than responsive throttles which have been resolved for some by remaping. One important thing to remember I am told, is to not touch the throttle on start up i.e rev or prime the throttle, as the ECU calibrates the DBW on start up.

 

Be careful not confuse throttle response with 'lag'. You can still have a car with minimal lag (ie the turbo comes on boost very early and is nearly always spooled up and ready for action) yet poor throttle response where the input through the accelerator is not mirrored by an instant response in the car. Shortest possible inlet tracts and a TMIC will help to keep a sharp throttle response, but you'll never have quite the crispness of a good NA car

 

fpan,

Do you mean throttle response in this respect:
https://www.scoobynet.com/general-te...-my06-sti.html

Nige.

 

4G63 is the engine used up to the Evo IX.

E46 M3 is also drive by wire and has no such issues. Properly mapped DBW should give no issues, the response time is much quicker than the time to change the speed of the turbine wheel.

Driving a turbocharged car is like controlling the throttle with elastic bands. I still love them.

 

No, not at all.

Couldn't have been put better

Lunar tick you are right, even when the turbo is spooling and at 6k rpm, playing with the throttle has not much effect. I guess I have yet to find the optimum rev range to drive the car on bends. Below 3k not much is happening and after 5.5k it feels as if running out of breath.
As lunar tick said "the input through the accelerator is not mirrored by an instant response in the car" a characteristic of most (if not all?) turbocharged cars I guess? I haven't driven any other turbocharged cars but instant throttle response makes you more connected with the car. The only 'drawback' of the subaru is that the chassis is so good that it forgives mistakes other cars wouldn't forgive. This doesn't make you a better driver though!
I like the subaru but miss my 205 still

 

My own experience is with my 2.5 STi Spec D (yes Spec D not Spec C) but I am sure the same principles apply.

There is an electronic 'tweak' available for the fly-by-wire throttle which improves the throttle response, I have had it done as part of the overall package of mods to my car and would definitely recommend it.

Yes a JDM twin scroll turbo will fit, I have one on my UK STi it does require changes to the exhaust as you need a different downpipe and centre section as they are different lengths etc to accommodate the different turbo. It obviously also requires a remap and in the case of my car I added a few other bits and pieces. I wasn't chasing figures, my requirement was for an exceptionally drive-able road car and I believe that has been achieved. I think this was part demonstrated by how close my car came to the Gobstopper in the handling competition at Scooby Shoot Out a few months ago! (Though of course the person driving it also played a very significant role in this).

I am not going to spoil it by saying too much beforehand but there is an upcoming magazine feature on my car which you may find interesting as it does feature two of the mods you are asking about.

Kind regards,

Robin

 

Hi RobinSherwood,
Who did the 'tweak' you mentioned and which magazine are you refering to?
When is the magazine going to be published?
Also where did you source the twin scroll turbo from?
Have you got any cats at all and does it pass MOTs?
Thanks a lot
Fivos

 

+1

 

The work was carried out by API API Engines and they also supplied the twin scroll, they got Bob Rawle in to do the final mapping. David O'Brien at API and Bob Rawle both advised on the spec to go for.

I'll have to check it is ok to answer the second question and don't know when it will be published as we only did the photo shoot a week ago. Will post the answers as soon as I know.

As far as MOT is concerned I will cross that bridge when the time comes next October but I have had decat cars before and have not had any problems.

Robin