Project STi Time Attack
Posted: Fri Aug 10, 2007 7:34 am
I thought I would do a copy and paste of a project thread I have had going over on BigPower - hopefully some of the issues that I have faced and solved may be of benefit to you here.
I apologise in advance for the length of it
I thought I would start a new project thread for my car to help me to prepare the car ready for Time Attack at the end of July up at Knockhill. If all goes to plan it should be almost ready for shakedown at Cadwell Park on the 16th July.
Issues:
1. Injector duty too high running at 95+% IDC at the moment even with 3.8 bar fuel pressure
2. Air restrictions caused by airbox
3. Oil throw issue on prolonged cornering causing catch can to fill within a few laps
4. Suspension needs to be lowered and reduction of body roll and allowing greater cornering speeds
5. Tyres ... I need some
6. Brakes
7. TA Specifics
Plan of Attack:
1. 800cc injectors are ready to be fitted along with adjustments to the mapping to suit and small increase of boost as we had to back it off to keep within 100% IDC. This should liberate the top end a little more where duty cycle issues really get highlighted. This will extend the available power range upwards slightly giving the option to hold a shorter gear through a section rather than short shifting prior to a corner.
Power-wise I would expect another 15-20 bhp from this in the peak region but more importantly give me IDC of 80% as a max.
2. APS 70mm inner-wing mounted induction kit arrives tomorrow and will get fitted before the injectors as it will be easier to adjust the MAF scaling first to suit this and then factor in higher flow injectors than the other way around. Aside from an increase in induction noise (which I personally dont like much) it will make the whole induction system flow better and should increase both torque and bhp figures a tad once mapped to suit
3. The Oil Throw issue needs solving as I do not want to be depositing oil onto the track for other competitors or for me to have a moment on. I have decided to go the whole hog this time and fit a 3 x inlet, 1 x breather and 1 drain 2.6 litre catch can from Roger Clark Motorsport. This will be aeroquipped to drain back any collected oil to the sump, thereby keeping the oil within the engine and not sprayed underneath my car Whereas 2.6 litres does seem excessively large, I am fed up with having to drain the catch can after half a dozen spirited laps.
The catch can does not catch hardly anything during normal road use even at high boost so can 100% be solved by this solution.
This is a photo of Bob Rawle's solution that I will be putting in place (although i will be using a banjo bolt rather than a straight feed):
4. Suspension - This is strangely a lower priority than the others but as my existing suspension seems to work ok enough as it stands, it would be great to make it better but not 100% essential if funds are limited. Shortlist at the moment is: EXE-TC and KW Variant 3.
5. Tyres - looking for a small supply of R rated, probably Yoko 048's 235/45/17 for my spare wheels (sponsors would be greatly appreciated on these )
6. Brakes - not really an issue now with the PF discs and pads but will be removing the backing plates and fitting cooling ducts to ensure that they stay as good as they can be.
7. TA specifics - I will need to go through the regs to ensure that the car will pass scrutineering.... be a bloody long way to go only to be turned away for a stupid thing
The end power result should be in the order of:
380 bhp
420 lb/ft
Not huge figures by the levels of some here, but with torque of over 350 lb/ft from 2800 to 5500rpm it should be pretty rapid around the track
I apologise in advance for the length of it
I thought I would start a new project thread for my car to help me to prepare the car ready for Time Attack at the end of July up at Knockhill. If all goes to plan it should be almost ready for shakedown at Cadwell Park on the 16th July.
Issues:
1. Injector duty too high running at 95+% IDC at the moment even with 3.8 bar fuel pressure
2. Air restrictions caused by airbox
3. Oil throw issue on prolonged cornering causing catch can to fill within a few laps
4. Suspension needs to be lowered and reduction of body roll and allowing greater cornering speeds
5. Tyres ... I need some
6. Brakes
7. TA Specifics
Plan of Attack:
1. 800cc injectors are ready to be fitted along with adjustments to the mapping to suit and small increase of boost as we had to back it off to keep within 100% IDC. This should liberate the top end a little more where duty cycle issues really get highlighted. This will extend the available power range upwards slightly giving the option to hold a shorter gear through a section rather than short shifting prior to a corner.
Power-wise I would expect another 15-20 bhp from this in the peak region but more importantly give me IDC of 80% as a max.
2. APS 70mm inner-wing mounted induction kit arrives tomorrow and will get fitted before the injectors as it will be easier to adjust the MAF scaling first to suit this and then factor in higher flow injectors than the other way around. Aside from an increase in induction noise (which I personally dont like much) it will make the whole induction system flow better and should increase both torque and bhp figures a tad once mapped to suit
3. The Oil Throw issue needs solving as I do not want to be depositing oil onto the track for other competitors or for me to have a moment on. I have decided to go the whole hog this time and fit a 3 x inlet, 1 x breather and 1 drain 2.6 litre catch can from Roger Clark Motorsport. This will be aeroquipped to drain back any collected oil to the sump, thereby keeping the oil within the engine and not sprayed underneath my car Whereas 2.6 litres does seem excessively large, I am fed up with having to drain the catch can after half a dozen spirited laps.
The catch can does not catch hardly anything during normal road use even at high boost so can 100% be solved by this solution.
This is a photo of Bob Rawle's solution that I will be putting in place (although i will be using a banjo bolt rather than a straight feed):
4. Suspension - This is strangely a lower priority than the others but as my existing suspension seems to work ok enough as it stands, it would be great to make it better but not 100% essential if funds are limited. Shortlist at the moment is: EXE-TC and KW Variant 3.
5. Tyres - looking for a small supply of R rated, probably Yoko 048's 235/45/17 for my spare wheels (sponsors would be greatly appreciated on these )
6. Brakes - not really an issue now with the PF discs and pads but will be removing the backing plates and fitting cooling ducts to ensure that they stay as good as they can be.
7. TA specifics - I will need to go through the regs to ensure that the car will pass scrutineering.... be a bloody long way to go only to be turned away for a stupid thing
The end power result should be in the order of:
380 bhp
420 lb/ft
Not huge figures by the levels of some here, but with torque of over 350 lb/ft from 2800 to 5500rpm it should be pretty rapid around the track