Impreza newbie
Discussion
Hi All,
Just bought myself a totally standard, UK supplied,1998 Impreza Turbo, 1 owner, 49,000 miles. I have bought the car with the sole intention of using it for trackdays.
I intend to make a few low cost mods. What are the normal mods that you make on these cars? I have had Porsches for the last 15 years and the turbo 4wd scene is all new to me.
My first thoughts are: air filter, decat, rear box, strut braces, brakes, brake pipes, brake fluid, etc
Are the standard brakes good enough with better pads, fluid, etc?
What is the best air filter to go for ? Does the bigger bore rear box make any real difference?
Any thoughts, advice would be very much appreciated
Kev
Just bought myself a totally standard, UK supplied,1998 Impreza Turbo, 1 owner, 49,000 miles. I have bought the car with the sole intention of using it for trackdays.
I intend to make a few low cost mods. What are the normal mods that you make on these cars? I have had Porsches for the last 15 years and the turbo 4wd scene is all new to me.
My first thoughts are: air filter, decat, rear box, strut braces, brakes, brake pipes, brake fluid, etc
Are the standard brakes good enough with better pads, fluid, etc?
What is the best air filter to go for ? Does the bigger bore rear box make any real difference?
Any thoughts, advice would be very much appreciated
Kev
Leave your engine absolutely bog standard until the ECU can be remapped (no solution right now apart from an expensive aftermarket ECU, but that will very soon be changing via ESL), and instead spend the money on proper handling and brake mods.
Big brake kit 330mm ront rear rotors with 8pots up front and 6pots rear with decent pads to match (K-Sport, D2 Racing, StopTech, Carbonetics, Performance Friction), and Bilstein or Eibach (adjustable) dampers and springs, front and rear strut top braces, lower front strut brace, front and rear uprated drop links, bigger rear anti-roll bar, anti-lift kit and a full set of front and rear uprated bushes then get a fast road geometry done and regardless of the standard power your car puts out with it handling that well no bugger will ever get anywhere near you, even much more powerful subaru's.
In my experience make your car handle and stop as well as it possibly can first of all so that it easily handles the current power output, and then get the engine mods and remapping done to suit.
Simples!!
Big brake kit 330mm ront rear rotors with 8pots up front and 6pots rear with decent pads to match (K-Sport, D2 Racing, StopTech, Carbonetics, Performance Friction), and Bilstein or Eibach (adjustable) dampers and springs, front and rear strut top braces, lower front strut brace, front and rear uprated drop links, bigger rear anti-roll bar, anti-lift kit and a full set of front and rear uprated bushes then get a fast road geometry done and regardless of the standard power your car puts out with it handling that well no bugger will ever get anywhere near you, even much more powerful subaru's.
In my experience make your car handle and stop as well as it possibly can first of all so that it easily handles the current power output, and then get the engine mods and remapping done to suit.
Simples!!
I mostly agree with ScoobieWRX.
I'd not bother with the anti lift kit myself - I always put it down as a "pro dive kit" when braking heavily. This could of course be because my car is a little bit non standard.
I have Godspeed 330mm 4 pot brakes on the front of mine, and I have never "run out of brakes" even when doing silly things. They use the subaru 4 pot calipers with spacers inserted so the bigger discs fit. These days, things have got cheaper so 8 pots are a bit more affordable so if you can, go for it. You certainly need some kind of brake upgrade, and certainly do the obvious things like braided hoses & good quality fluid.
I have AST coilovers on my car. They work pretty well - my car is certainly competitive in local autotests (but I am not yet!), but there are better things if you have a bigger budget. Again, suspension is worth upgrading for the track, but I would place it at a lower priority to the brakes - standard dampers with eibach springs are quite good and usable.
If you absolutely must do some engine mods, then avoid oily air filters since they risk clogging the airflow sensor (this causes lean running and can lead to nasty expensive things happening). Changing the backbox will just make more noise but no more power. Not good for tracks with low noise limits. Taking the main cat (in the downpipe) out will improve spool and give a decent power gain, but without a remap you risk detonation - specially given your desire for thrashing on a track! MOTs can be passed with just the centre cat in place. It's easier to leave it alone until either ESL make their remap device work or you can throw considerable cash at the problem. It is certainly worth it if the rest of the car is up to the job.
I would suggest a knock monitor as a prudent precaution even for a standardish car if it is just used on the track. Something like the old fashioned "knocklink" would do, but there are better products around now (although names escape me)
I'm currently building a 1994 WRX wagon for the PPC £999 challenge, so we may well be in a position to compare notes about the current state of the market. And my profile details most of what's been done to my STI RA - it may give you some ideas.
I'd not bother with the anti lift kit myself - I always put it down as a "pro dive kit" when braking heavily. This could of course be because my car is a little bit non standard.
I have Godspeed 330mm 4 pot brakes on the front of mine, and I have never "run out of brakes" even when doing silly things. They use the subaru 4 pot calipers with spacers inserted so the bigger discs fit. These days, things have got cheaper so 8 pots are a bit more affordable so if you can, go for it. You certainly need some kind of brake upgrade, and certainly do the obvious things like braided hoses & good quality fluid.
I have AST coilovers on my car. They work pretty well - my car is certainly competitive in local autotests (but I am not yet!), but there are better things if you have a bigger budget. Again, suspension is worth upgrading for the track, but I would place it at a lower priority to the brakes - standard dampers with eibach springs are quite good and usable.
If you absolutely must do some engine mods, then avoid oily air filters since they risk clogging the airflow sensor (this causes lean running and can lead to nasty expensive things happening). Changing the backbox will just make more noise but no more power. Not good for tracks with low noise limits. Taking the main cat (in the downpipe) out will improve spool and give a decent power gain, but without a remap you risk detonation - specially given your desire for thrashing on a track! MOTs can be passed with just the centre cat in place. It's easier to leave it alone until either ESL make their remap device work or you can throw considerable cash at the problem. It is certainly worth it if the rest of the car is up to the job.
I would suggest a knock monitor as a prudent precaution even for a standardish car if it is just used on the track. Something like the old fashioned "knocklink" would do, but there are better products around now (although names escape me)
I'm currently building a 1994 WRX wagon for the PPC £999 challenge, so we may well be in a position to compare notes about the current state of the market. And my profile details most of what's been done to my STI RA - it may give you some ideas.
The standard ECU has excellent knock control and will retard timing, add fuelling, lower boost etc.. to save your engine if it detects knock. An ESL remap could utilise the check engine light to act as a knock light which might be an aid to getting you to back right off when you see the light which is always a help but if you do get a bad bout of knock, specially at either peak engine load or high revs and you have no knock control you cannot react more quickly than the ECU, so likely your engine will go pop.
There are very simple and effective knocklights around for about £100 that will gradually indicate through several LEDS just how much knock you're getting. They are a good idea because you can tell at a glance without having to read an LCD screen (like on a KS3/4), if you're pushing just a bit too hard.
Get the car dancing first, then teach it how to sing!!
There are very simple and effective knocklights around for about £100 that will gradually indicate through several LEDS just how much knock you're getting. They are a good idea because you can tell at a glance without having to read an LCD screen (like on a KS3/4), if you're pushing just a bit too hard.
Get the car dancing first, then teach it how to sing!!
V1 and V2 Jecs ECU's run a closed loop knock control so they all pull timing, add fuel and modify boost upon detecting knock and have the ability to lower the IAM (initial avanced multiplier) so low that the car runs in effect, in limp mode. All later Subaru ECU's do exactly the same.
Subaru didn't spend billions in R&D to design an ECU, manufactured by someone else, but to Subaru specs, that was also used in WRC, and that didn't have all out safety in mind.
Subaru equipped all their cars with what are the best ECU's on the planet. You will have to go a bloody long way and spend a fortune to get an afteramrket ECU as sophisticated as these. The only problem with the V1/V2 ECU and the 97/98 ECU's, is that you can't flash them, however, ESL cracked the V1/V2 ECU and came out with their own solution which is a daughterboard fitted to the ECU's expansion port, that allows a tuner to manipulate all the numbers on the std ECU. They are currently doing exactly the sme for 97/98 V3/V4 ECU's. That solution should be out sometime soon, i hope
Subaru didn't spend billions in R&D to design an ECU, manufactured by someone else, but to Subaru specs, that was also used in WRC, and that didn't have all out safety in mind.
Subaru equipped all their cars with what are the best ECU's on the planet. You will have to go a bloody long way and spend a fortune to get an afteramrket ECU as sophisticated as these. The only problem with the V1/V2 ECU and the 97/98 ECU's, is that you can't flash them, however, ESL cracked the V1/V2 ECU and came out with their own solution which is a daughterboard fitted to the ECU's expansion port, that allows a tuner to manipulate all the numbers on the std ECU. They are currently doing exactly the sme for 97/98 V3/V4 ECU's. That solution should be out sometime soon, i hope
I disassembled the code in the V1 ECU. It only pulls timing for knocking.
Unless you are refering to the "sulk mode" where it limits boost to 0.7 bar under certain fault conditions (not all knock related) or the overboost fuel cut?
BTW, I managed to get MAFless operation without a CEL too - but table resolution was too poor for daily use.
Unless you are refering to the "sulk mode" where it limits boost to 0.7 bar under certain fault conditions (not all knock related) or the overboost fuel cut?
BTW, I managed to get MAFless operation without a CEL too - but table resolution was too poor for daily use.
Edited by dnb on Saturday 15th May 12:58
dnb said:
I disassembled the code in the V1 ECU. It only pulls timing for knocking.
Unless you are refering to the "sulk mode" where it limits boost to 0.7 bar under certain fault conditions (not all knock related) or the overboost fuel cut?
BTW, I managed to get MAFless operation without a CEL too - but table resolution was too poor for daily use.
You should be tuning Subaru's then because disassembling code and identifying all the maps is not the easiest thing to do. You need a deep understanding of software and strong appreciation of automotive engineering/theory. Mind you i've just seen your occupation and it states...Sytems Engineer. No wonder!! Unless you are refering to the "sulk mode" where it limits boost to 0.7 bar under certain fault conditions (not all knock related) or the overboost fuel cut?
BTW, I managed to get MAFless operation without a CEL too - but table resolution was too poor for daily use.
Edited by dnb on Saturday 15th May 12:58
Have you identified every single map??
Answering Kev's questions first:
UK cars had a cat in the downpipe and another in the centre section of the exhaust. Some grey imports only had the downpipe cat, and I think the Prodrive performance pack deleted the centre cat too.
I have front and rear upper braces, so can't quantify improvements from lower braces. It's something that would get done if I happened to find one at the right price.
As for mapping Subarus - I've been mapping the odd car for several years now, but strictly as a hobby. (Radar systems engineering tends to provide a more regular income ) I have found all the tables I need to do everything I need for the tuning I have done, but there are probably some sigle value variables (ie a single byte or word) I haven't identified or have forgotten about... I haven't looked at this much in the last year or two.
Some tables I don't fully understand the units, but most of these don't seem to need changing too often so I haven't exactly applied myself to completely understanding them. The v1 Subau ECU is very advanced considering it was designed in the late 80s and early 1990s!
UK cars had a cat in the downpipe and another in the centre section of the exhaust. Some grey imports only had the downpipe cat, and I think the Prodrive performance pack deleted the centre cat too.
I have front and rear upper braces, so can't quantify improvements from lower braces. It's something that would get done if I happened to find one at the right price.
As for mapping Subarus - I've been mapping the odd car for several years now, but strictly as a hobby. (Radar systems engineering tends to provide a more regular income
) I have found all the tables I need to do everything I need for the tuning I have done, but there are probably some sigle value variables (ie a single byte or word) I haven't identified or have forgotten about... I haven't looked at this much in the last year or two.Some tables I don't fully understand the units, but most of these don't seem to need changing too often so I haven't exactly applied myself to completely understanding them. The v1 Subau ECU is very advanced considering it was designed in the late 80s and early 1990s!
dnb said:
Answering Kev's questions first:
UK cars had a cat in the downpipe and another in the centre section of the exhaust. Some grey imports only had the downpipe cat, and I think the Prodrive performance pack deleted the centre cat too.
I have front and rear upper braces, so can't quantify improvements from lower braces. It's something that would get done if I happened to find one at the right price.
As for mapping Subarus - I've been mapping the odd car for several years now, but strictly as a hobby. (Radar systems engineering tends to provide a more regular income ) I have found all the tables I need to do everything I need for the tuning I have done, but there are probably some sigle value variables (ie a single byte or word) I haven't identified or have forgotten about... I haven't looked at this much in the last year or two.
Some tables I don't fully understand the units, but most of these don't seem to need changing too often so I haven't exactly applied myself to completely understanding them. The v1 Subau ECU is very advanced considering it was designed in the late 80s and early 1990s!
You should maybe think about the ESL solution which just plugs a daughterboard into the expansion port on the board and hooks up via the comms connector under the dash. It's live mapping and would give you a lot of pleasure mapping your own seeing as you have some experience.UK cars had a cat in the downpipe and another in the centre section of the exhaust. Some grey imports only had the downpipe cat, and I think the Prodrive performance pack deleted the centre cat too.
I have front and rear upper braces, so can't quantify improvements from lower braces. It's something that would get done if I happened to find one at the right price.
As for mapping Subarus - I've been mapping the odd car for several years now, but strictly as a hobby. (Radar systems engineering tends to provide a more regular income
) I have found all the tables I need to do everything I need for the tuning I have done, but there are probably some sigle value variables (ie a single byte or word) I haven't identified or have forgotten about... I haven't looked at this much in the last year or two.Some tables I don't fully understand the units, but most of these don't seem to need changing too often so I haven't exactly applied myself to completely understanding them. The v1 Subau ECU is very advanced considering it was designed in the late 80s and early 1990s!
BTW...small world...I was in electronics recruitment for over 20 years and dealt with the likes of Plessey Radar (as they were way back when), Milmega, and Pascall. I know of Vectawave too so it wouldn't surprise me if you're somewhere in that mire.
You've got me pegged - a Plessey Radar derived company
I would have used the ESL solution, but I happened to have a spare VEMS ECU kicking around so it's going in my V1 track car. Live mapping is the way forward
The v5 doesn't need anything doing other than some handling tweaks now I have changed the wheel size.
I would have used the ESL solution, but I happened to have a spare VEMS ECU kicking around so it's going in my V1 track car. Live mapping is the way forward
The v5 doesn't need anything doing other than some handling tweaks now I have changed the wheel size. 
ked the budget part lolYes well ESL should have something out shortly for the 97/98 cars. I know it's been going on for ages but i think they are genuinely not too far away now from the finished fully tested article, and that should be priced around the same as 92-96 version prices.
Again it's very good solution for the money and will come with all the same facilities as earlier version daughterboards. MAFLESS option, Launch Control, switchable mapping and Flat Foot Shifting (ALS).
Your product though Charlie is in a different league/level whatever you want to call it to ESL and likely better than most if not all aftermarket ECU's for Subaru's.
I have to say though, when i can do no more with my std newage Denso ECU i don't have to think too hard about where to go for an aftermarket option. Duncan loves your ECU and has done very well with it, and Zen did very well with it too so it's an easy decision for me.
You'll definately get my business when i'm ready to rock and roll.
Again it's very good solution for the money and will come with all the same facilities as earlier version daughterboards. MAFLESS option, Launch Control, switchable mapping and Flat Foot Shifting (ALS).
Your product though Charlie is in a different league/level whatever you want to call it to ESL and likely better than most if not all aftermarket ECU's for Subaru's.
I have to say though, when i can do no more with my std newage Denso ECU i don't have to think too hard about where to go for an aftermarket option. Duncan loves your ECU and has done very well with it, and Zen did very well with it too so it's an easy decision for me.
You'll definately get my business when i'm ready to rock and roll.
Vixpy1 said:
One of these days we are going to get you to junk that Vems Davud! And not for a sodding ESL board either!
Unless a Syvecs comes for "free", the £999 challenge simply has to be done with parts from my scrap bin... The TVR is another story once certain other things have happened.
Rob knows some of the plan.Edited by dnb on Sunday 16th May 10:31
dnb said:
Vixpy1 said:
One of these days we are going to get you to junk that Vems Davud! And not for a sodding ESL board either!
Unless a Syvecs comes for "free", the £999 challenge simply has to be done with parts from my scrap bin... The TVR is another story once certain other things have happened.
Rob knows some of the plan.Edited by dnb on Sunday 16th May 10:31
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