SEAT Ibiza - rwd turbo
Discussion
Well, after a bit of a hiatus getting distracted with other projects, i thought i'd try and get my little 'bitza finished. It's beeen sat in the corner of the garage being ignored for about 14months, so it was off with the covers and out into the sun today:
There are a few little jobs to do, and it needs a bit of mapping with the new knock control ecu, but i can feel a track day beckoning!
There are a few little jobs to do, and it needs a bit of mapping with the new knock control ecu, but i can feel a track day beckoning!
At the moment i can't decide if i'm going to MOT it. It was originally going to be a tarmac rally car (before the MSA banned such things for being too much fun........) so can be made road legal pretty easily (just needs a mech handbrake adding to comply). But, it's a right PITA to drive at low speed, with an ultra low intertia engine, carbon/carbon triple plate clutch, sequential dog box and 1st good for 60mpg, getting into going, and driving at low speeds is really very tricky indeed!
Spec wise, it's a smidge over 940kg as it sits, with a fairly trick 2l turbo engine, mounted longitudinally upfront (well, mid front really) driving back through an engine speed carbon prop to a quaiffe 6spd seq dogbox mounted under the rear floor, and finally into a BMW M diff. Suspension is WRC uprights / proflex all round, brakes are 380mm front 6 pots, and 340mm rear 4 pots. All the body work is carbon or kelvar, with custom wide arches, perspex windows, and a pretty comprehensive multipoint cage.
;-)
Spec wise, it's a smidge over 940kg as it sits, with a fairly trick 2l turbo engine, mounted longitudinally upfront (well, mid front really) driving back through an engine speed carbon prop to a quaiffe 6spd seq dogbox mounted under the rear floor, and finally into a BMW M diff. Suspension is WRC uprights / proflex all round, brakes are 380mm front 6 pots, and 340mm rear 4 pots. All the body work is carbon or kelvar, with custom wide arches, perspex windows, and a pretty comprehensive multipoint cage.
;-)
5RedLights said:
Awesome.
I'm guessing the laptop isn't for periodical facebook checks?
correct, i'm more of a Twitter man tbh......... ;-)I'm guessing the laptop isn't for periodical facebook checks?
There are a lot of custom electronics controlling systems on the car, which take a bit of setting up! The main engine controller is a Motec unit, and it runs my own custom systems driving:
Electronically actuated port throttle system,
High pressure (6-9bar) returnless pressure controlled fuel delivery system,
Pneumatic gear shift system for the transmission (inc flatupshift/downshiftrevmatching)
Cylinder specific, adaptive knock sensing controller,
Multirunner Crank Angle PLL'd manifold pressure sensor system
Cooling FAN speed control module for rad / IC fans
Various CAN devices for intermodule coms and I/O driving
Manifold Water injection and I/C water spray controller
CAN controller for the EHPAS system, with steering angular rate / roadspeed dependent calibration
Edited by anonymous-user on Friday 27th September 11:16
chuntington101 said:
aka_kerrly said:
Fascinating build with an incredible specification.
Is the engine not a VAG 20vt unit?
Think its a Renault unit actually! Sure Max will be on to confirm. Is the engine not a VAG 20vt unit?
Edited by anonymous-user on Friday 27th September 20:28
I've also got to finish my custom trailer designed to carry the 'Bitza. Because the car is very wide across the wheel centres, it needs a wide trailer to get onto, but then that wide trailer is too wide to go into my garage (and leaving trailers outside in full view is asking for trouble) so i have designed a trailer that expands hydraulically width wise when being towed, but narrows itself to be stored!
I will also be using the car to develop my race ABS system (see thread in Engines & Drivetrains) so a bit of looming needs to go in for that too. If i am feeling really keen, i'd also like to swap to a hand clutch (only used to get moving, then fully clutchless) and a floor mounted pedal box to get some of the mass down lower.
I will also be using the car to develop my race ABS system (see thread in Engines & Drivetrains) so a bit of looming needs to go in for that too. If i am feeling really keen, i'd also like to swap to a hand clutch (only used to get moving, then fully clutchless) and a floor mounted pedal box to get some of the mass down lower.
Back in 2000, i was looking for a new tarmac spec rally car to replace my Volvo: (which was destroyed in a multiple roll)
And pretty much just the engine was all that was left! I wanted something a bit more forgiving to drive than a mid engined car, and thought that front mid engine, rear transmission was a decent compromise. With a higher polar moment of inertia than a mid engined car for stability, but still enough mass on the back axle to get good accel from low vehicle speeds (critical in the tight twisty UK tarmac stage rallying). At the time, there were plenty of non-homologated classes for "homebuilt" specials, and several people had been doing very well up against the heavier GrpA 4x4 cars on tarmac.
As such, i wanted a compact car, that had short overhangs but a decently long wheelbase, and of course SEAT had some success with the FWD 2.0 Cupra in the 'Kitcar' class. So the search started for a suitable donor car.
I found a stolen recovered Ibiza 1.4 SXE 3 door, that had been a motability car, which the owner had unfortunately left the keys in the ignition at a petrol station, and some chancers had just driven it away! They had eventually run out of fuel, driven it into a field, broken a cigarette lighter over the rear seats, chucked in a match, slammed the door and done a runner. Unfortunately for them, and luckily for me, cars are pretty air tight these days, so after a few mins smouldering, the fire when out! The interior was heavily smoke damaged, hence the car was written off, but i knew all the interior was going in the bin, so for the princely sum of £1800 i had a 2 yo car, with less than 12k on the clock, and in perfect mechanical condition!
I immediately stripped the interior out, stuck in some bucket seats, and put on some big wheels to see how the car worked with more rubber on the road:
And the answer was of course, it was terrible! With std sized wheel houses and a narrow(ish) track, the car simply couldn't deal with any bumps at all, and had no wheel travel really. So i immediately knew that some serious surgery would be required. I actually drove the car for about a year like that, and weighing just 760kg even with 80hp it actually went reasonably well. During that time i formulated plans and started collecting parts for the grand design!
And pretty much just the engine was all that was left! I wanted something a bit more forgiving to drive than a mid engined car, and thought that front mid engine, rear transmission was a decent compromise. With a higher polar moment of inertia than a mid engined car for stability, but still enough mass on the back axle to get good accel from low vehicle speeds (critical in the tight twisty UK tarmac stage rallying). At the time, there were plenty of non-homologated classes for "homebuilt" specials, and several people had been doing very well up against the heavier GrpA 4x4 cars on tarmac.
As such, i wanted a compact car, that had short overhangs but a decently long wheelbase, and of course SEAT had some success with the FWD 2.0 Cupra in the 'Kitcar' class. So the search started for a suitable donor car.
I found a stolen recovered Ibiza 1.4 SXE 3 door, that had been a motability car, which the owner had unfortunately left the keys in the ignition at a petrol station, and some chancers had just driven it away! They had eventually run out of fuel, driven it into a field, broken a cigarette lighter over the rear seats, chucked in a match, slammed the door and done a runner. Unfortunately for them, and luckily for me, cars are pretty air tight these days, so after a few mins smouldering, the fire when out! The interior was heavily smoke damaged, hence the car was written off, but i knew all the interior was going in the bin, so for the princely sum of £1800 i had a 2 yo car, with less than 12k on the clock, and in perfect mechanical condition!
I immediately stripped the interior out, stuck in some bucket seats, and put on some big wheels to see how the car worked with more rubber on the road:
And the answer was of course, it was terrible! With std sized wheel houses and a narrow(ish) track, the car simply couldn't deal with any bumps at all, and had no wheel travel really. So i immediately knew that some serious surgery would be required. I actually drove the car for about a year like that, and weighing just 760kg even with 80hp it actually went reasonably well. During that time i formulated plans and started collecting parts for the grand design!
The main aim was to make one of these:
But with about twice the power!
As the regs stood in 2001/2, the min class weight (2wd) was 1060kg, so that gave a target to aim for, ideally being under 1000kg, so i could use the position of the MSA ballast as a handling trim. The engine, being forced induction attracted a 1.4x capacity multiplier, so 2.0 litres was the largest i could run, and a 38mm inlet restrictor was mandatory pre-compressor. This relatively large restrictor mean't just about 400bhp was possible, giving the turbo engines the edge over the high rpm N/A engines (Millingtons, NA YB's, XE's etc), and the potential for a much wider torque band. The problem with my current Renault engine is that it was difficult to make good top end power, without the mid range torque becoming so enormous and "sudden" that a 2wd car struggled to put it down.
Often, my previous rally car would wheelspin early, needing a throttle lift right at the moment peak power arrived, where a more progressive delivery would have resulted in an earlier higher longitudinal accel, and hence the rear tyres could have transmitted the peak power number to the ground. As such, i knew major engine revisions would be required, with a focus on moving the torque peak up the rev range, and developing a "driveable" engine. Key to this would be turbo, intake and EMS systems chosen, taking into account advances in electronic control for things like AntiLag and reduced gearshift duration.
Transmission wise, there was really only 1 architecture that would work, a sequential dog box. The problem with that was simply the cost of such a gearbox!
The plan to use genuine SEAT Kitcar parts came to nothing when costs were investigated. As the F2 regs required panels to be made from "original materials" the Kitcars used pressed steel wide arches, and SEAT sport wanted £1200 per corner..... (they had massive press tooling costs to recover!). Whilst that was just affordable once, given that rally cars spend quite a bit of time getting dented, it would not be a sustainable expense. This lead to a cheap, but time consuming process of doing my own Kevlar arches and panels!
Likewise, the F2 roll cage simply didn't work with my car, due to the positioning of things like the transmission tunnel, suspension turrets and engine orientation. As such, the cage in my car uses the genuine Safety Devices main cage "hoops" from the F2 cage, but all other tubes are custom to suit
Suspension wise, i knew the car needed good quality damping, but that ultimate cornering loads would be relatively low (heavy car, high CofG, Often low friction of "tarmac" surface), and that it would need to be very robust to withstand the rigures of rallying (kerbs, potholes, jumps, ditch hooking etc). This meant a simple Strut and wishbone style system at each corner was a good compromise, giving decent control of wheel paths without excessive complexity. It did mean that a high dynamic roll stiffness would be required however, as with struts, bodyroll is very nearly 1:1 with tyre camber change. As such, tuning the initial camber setting and the front rear ARB stiffness would be critical. At the time, there were a lot of people chopping in GrpA cars for the first of the hand-me-down WRC cars, and hence using suspension from those was a sensible move, FORD Escort GrpA/WRC uprights and dampers effectively. Whilst i wanted a low car to reduce the lateral mass transfer and that critical bodyroll, i wanted long wheel travel to "swallow" potholes, and drop into the bottoms of ditches/cambers etc. The aim was maximum traction at all times, even at the slight expense to pure handling. Hence the original Ibiza's wheel houses and damper turrets would need extensive revision to accommodate those movements. The final piece in the puzzle was to make the car as wide across the track as possible. This is a compromise between roll stiffness / low lateral mass transfer and agility. The typical UK tarmac stage rally can be quite tight in places, especially the artificial "bale" chicanes the organisers loved to put in to try slow us down a bit! As a purely tarmac car however, there were less concerns of "fitting into the ruts left by others" as in gravel rallying, so i knew i could go to a wider track then the dual surface F2 kitcars. To restore some low speed agility, a high ratio steering system would be required, and the hunt was on for a steering rack and system to deliver this with sufficient lateral stiffness / robustness.
So in summary the plan became:
Under 1 tonne, all the mass low and between the wheels, low ride height, but with lots of travel, ultra wide track, quick steering, high power at high rpm, sequential transmission.
Sounds easy doesn't it............ ;-)
Next - Get that angle grinder out !
But with about twice the power!
As the regs stood in 2001/2, the min class weight (2wd) was 1060kg, so that gave a target to aim for, ideally being under 1000kg, so i could use the position of the MSA ballast as a handling trim. The engine, being forced induction attracted a 1.4x capacity multiplier, so 2.0 litres was the largest i could run, and a 38mm inlet restrictor was mandatory pre-compressor. This relatively large restrictor mean't just about 400bhp was possible, giving the turbo engines the edge over the high rpm N/A engines (Millingtons, NA YB's, XE's etc), and the potential for a much wider torque band. The problem with my current Renault engine is that it was difficult to make good top end power, without the mid range torque becoming so enormous and "sudden" that a 2wd car struggled to put it down.
Often, my previous rally car would wheelspin early, needing a throttle lift right at the moment peak power arrived, where a more progressive delivery would have resulted in an earlier higher longitudinal accel, and hence the rear tyres could have transmitted the peak power number to the ground. As such, i knew major engine revisions would be required, with a focus on moving the torque peak up the rev range, and developing a "driveable" engine. Key to this would be turbo, intake and EMS systems chosen, taking into account advances in electronic control for things like AntiLag and reduced gearshift duration.
Transmission wise, there was really only 1 architecture that would work, a sequential dog box. The problem with that was simply the cost of such a gearbox!
The plan to use genuine SEAT Kitcar parts came to nothing when costs were investigated. As the F2 regs required panels to be made from "original materials" the Kitcars used pressed steel wide arches, and SEAT sport wanted £1200 per corner..... (they had massive press tooling costs to recover!). Whilst that was just affordable once, given that rally cars spend quite a bit of time getting dented, it would not be a sustainable expense. This lead to a cheap, but time consuming process of doing my own Kevlar arches and panels!
Likewise, the F2 roll cage simply didn't work with my car, due to the positioning of things like the transmission tunnel, suspension turrets and engine orientation. As such, the cage in my car uses the genuine Safety Devices main cage "hoops" from the F2 cage, but all other tubes are custom to suit
Suspension wise, i knew the car needed good quality damping, but that ultimate cornering loads would be relatively low (heavy car, high CofG, Often low friction of "tarmac" surface), and that it would need to be very robust to withstand the rigures of rallying (kerbs, potholes, jumps, ditch hooking etc). This meant a simple Strut and wishbone style system at each corner was a good compromise, giving decent control of wheel paths without excessive complexity. It did mean that a high dynamic roll stiffness would be required however, as with struts, bodyroll is very nearly 1:1 with tyre camber change. As such, tuning the initial camber setting and the front rear ARB stiffness would be critical. At the time, there were a lot of people chopping in GrpA cars for the first of the hand-me-down WRC cars, and hence using suspension from those was a sensible move, FORD Escort GrpA/WRC uprights and dampers effectively. Whilst i wanted a low car to reduce the lateral mass transfer and that critical bodyroll, i wanted long wheel travel to "swallow" potholes, and drop into the bottoms of ditches/cambers etc. The aim was maximum traction at all times, even at the slight expense to pure handling. Hence the original Ibiza's wheel houses and damper turrets would need extensive revision to accommodate those movements. The final piece in the puzzle was to make the car as wide across the track as possible. This is a compromise between roll stiffness / low lateral mass transfer and agility. The typical UK tarmac stage rally can be quite tight in places, especially the artificial "bale" chicanes the organisers loved to put in to try slow us down a bit! As a purely tarmac car however, there were less concerns of "fitting into the ruts left by others" as in gravel rallying, so i knew i could go to a wider track then the dual surface F2 kitcars. To restore some low speed agility, a high ratio steering system would be required, and the hunt was on for a steering rack and system to deliver this with sufficient lateral stiffness / robustness.
So in summary the plan became:
Under 1 tonne, all the mass low and between the wheels, low ride height, but with lots of travel, ultra wide track, quick steering, high power at high rpm, sequential transmission.
Sounds easy doesn't it............ ;-)
Next - Get that angle grinder out !
Edited by anonymous-user on Sunday 29th September 13:20
Zmaster2k said:
Where did you get some of the parts?! Want for my f7r!
Unfortunately, most of it is custom to my car.....Head gasket and Wills rings are from a Megane Ice Racer, Intake & exhaust valves / springing from the PeugeotSport Pikes peak Mi16 turbo, Con rods are "off the shelf" Arrow, throttle bodies are from Jenvey, Cam vernier wheels from KentCams.
Everything else is custom to my engine!
So, with plans sorted (ish) the butchery started!
The car was stripped back to a bare shell, and all the original mechanicals / suspension etc disposed of, then the roof panel was removed to help with the cage install (had to come off anyway as unfortunately the original had a sunroof hole in it).
(apologies for the poor photo quality, the early pics are scanned in from film!)
Checking clearance between steering column/pedal box and engine, especially the intake system. Due to the unavailability of high ratio RHD steering racks (WRC cars are LHD!), it was obvious the car would have to be LHD, not a problem as my daily at the time was an Integrale Evo ;-)
Left over volvo strut used temporarily to place a front wheel in place, allowing estimation of track width and wheel clearance to shell hard points. Also, the rollcage hoops have been trial fitted:
Originally i experimented with a Cosworth cast ally front subframe, seen in the this pic, but it proved to be unworkable and resultant suspension geo would have been poor at low ride heights. Also shown are the "banded" front turrets, used to lift the suspension top mounts up further into the shell to supply some much needed extra travel. Luckily, the front wheel houses are quite generous and little modification was required to the inner steelwork.
The ex volvo spec engine was dropped into the hole to see how far back and down it could be mounted. Unfortunately the F7 engines are long stroke and hence quite tall, so it was immediately obvious that a very low profile dry sump system would be required to get the engine low enough:
It became clear that a low mounted engine, tilted to the right (passenger side) would allow for the lighter intake system (later very light as it was re-made from carbon fibre!) to be lifted up above the pedal box and steering column, and the heavy turbo and exhaust manifold to be dropped downwards, allowing for a decent length exhaust primaries, and a nice straight exit run for a big bore exhaust system down the transtunnel.
Accurate measurements where taken from shell hard points for subframe mountings, and lots of measurements and head scratching occurred for things like bulkhead cutting and rear floor mods to accept the differential / gearbox etc.
The car was stripped back to a bare shell, and all the original mechanicals / suspension etc disposed of, then the roof panel was removed to help with the cage install (had to come off anyway as unfortunately the original had a sunroof hole in it).
(apologies for the poor photo quality, the early pics are scanned in from film!)
Checking clearance between steering column/pedal box and engine, especially the intake system. Due to the unavailability of high ratio RHD steering racks (WRC cars are LHD!), it was obvious the car would have to be LHD, not a problem as my daily at the time was an Integrale Evo ;-)
Left over volvo strut used temporarily to place a front wheel in place, allowing estimation of track width and wheel clearance to shell hard points. Also, the rollcage hoops have been trial fitted:
Originally i experimented with a Cosworth cast ally front subframe, seen in the this pic, but it proved to be unworkable and resultant suspension geo would have been poor at low ride heights. Also shown are the "banded" front turrets, used to lift the suspension top mounts up further into the shell to supply some much needed extra travel. Luckily, the front wheel houses are quite generous and little modification was required to the inner steelwork.
The ex volvo spec engine was dropped into the hole to see how far back and down it could be mounted. Unfortunately the F7 engines are long stroke and hence quite tall, so it was immediately obvious that a very low profile dry sump system would be required to get the engine low enough:
It became clear that a low mounted engine, tilted to the right (passenger side) would allow for the lighter intake system (later very light as it was re-made from carbon fibre!) to be lifted up above the pedal box and steering column, and the heavy turbo and exhaust manifold to be dropped downwards, allowing for a decent length exhaust primaries, and a nice straight exit run for a big bore exhaust system down the transtunnel.
Accurate measurements where taken from shell hard points for subframe mountings, and lots of measurements and head scratching occurred for things like bulkhead cutting and rear floor mods to accept the differential / gearbox etc.
Next steps was lots of CAD work, unfortunately in only 2d, as back then, 3d packages were the preserve of richer people than I.......
Initial schemes soon showed that anything using road based uprights was simply not going to work at low ride heights, and was unlikely to provide enough strength and stiffness in a competition environment:
That pretty much forced an (expensive) move to pukka rally parts, in this case, FORD escort WRC uprights:
FRONT:
REAR:
With Proflex supplying their low friction 4way adjustable remote resevoir struts, the geometry of the subframes and support components could now be optimised:
By this time i had already lost count as to the number of custom CNC'd parts required to optimise this design, and i was really only just starting!
First trial run fabricated parts were made to check fit and establish there suitability, and as usual lead to immediate changes and modifications. Originally i planned to use a Ford based rear differential, and the first rear subframe was designed to incorporate that:
As parts arrived, they were fitted and checked, here the front struts and uprights:
It became clear very quickly that a wider bodykit was going to be needed!
NEXT - Transmission and Torque tube forces major floorpan mods!
Initial schemes soon showed that anything using road based uprights was simply not going to work at low ride heights, and was unlikely to provide enough strength and stiffness in a competition environment:
That pretty much forced an (expensive) move to pukka rally parts, in this case, FORD escort WRC uprights:
FRONT:
REAR:
With Proflex supplying their low friction 4way adjustable remote resevoir struts, the geometry of the subframes and support components could now be optimised:
By this time i had already lost count as to the number of custom CNC'd parts required to optimise this design, and i was really only just starting!
First trial run fabricated parts were made to check fit and establish there suitability, and as usual lead to immediate changes and modifications. Originally i planned to use a Ford based rear differential, and the first rear subframe was designed to incorporate that:
As parts arrived, they were fitted and checked, here the front struts and uprights:
It became clear very quickly that a wider bodykit was going to be needed!
NEXT - Transmission and Torque tube forces major floorpan mods!
Trtj said:
The process of making the kevlar panels, how complex was this? Did you have to make your own moulds and tooling? Very impressive!
Unfortunately i haven't got many pics of this bit, as sticky, smelly, resins and cameras doesn't really go together! But basically, i reworked the metal work by welding in sections, and then used fibreglass cloth, body filler, expanding foam, and even chicken wire to form plugs of the shape of the wings, in place on the car. Then i took from this a female fibreglass mold. From those molds i made the actual parts from kevlar cloth. It's not difficult, but it is time consuming, and getting a good finish and good surfacing takes time. If i did it again now i'd go straight to 3d CAD and foam milling to make the plugs! (quicker, and much more repeatable)Trtj said:
With the cage, surely a butchered/hybrid cage will no longer be MSA/FIA approved? How do you get around this?
The cage was approved by SD after inspection. As the main hoops are original, and only the "straight" bars changed the MSA had no issues with the mods. if you were to modify the bent components it would be much more difficult to claim the original homologation still stood.Trtj said:
Finally with the suspension... How do you control the camber change with a single strut and wishbone pivot type? Is the camber just described by the radius of the wishbone travel about the pivot and you are stuck with that? Do current WRC cars still use single strut and wishbones front and rear?
Pretty much, you don't! Some tricks are availible, like using lots of castor to help with camber gain at high steering angles, but generally speaking you can't do a lot about it. For a circuit car, that experiences high lateral G, it would not be optimium, but for a much lower loaded rally car, the other virtues (strength, simplicity etc) win through. Pretty much all the WRC cars use struts at both ends for those reasons.Little video taster:
Start-Rev-ALS
Sorry, not much, will get some proper footage soon!
(CAUTION: contains gratuitous Antilag Action........ ;-)
Start-Rev-ALS
Sorry, not much, will get some proper footage soon!
(CAUTION: contains gratuitous Antilag Action........ ;-)
IanUAE said:
A question if I may. Are you going to duct the air that has past through the radiator into the bonnet vents?
We recently moved the engine back and down in our 120d race car and fitted similar bonnet vents and ducted the air into the vents to help manage the airflow.
That is the plan. In fact, with the main engine cooling rad being at the bottom, there is very much a danger of convection from the hotter rad resulting in unwanted upheat into the intercooler. With the water cooling rad running at around 90degC, and the IC at under 50, this can cause significant heat soak at low speeds (where convection is dominant)We recently moved the engine back and down in our 120d race car and fitted similar bonnet vents and ducted the air into the vents to help manage the airflow.
The flip side is maintaining a suitable level of ambient cooling airflow around the rest of the engine bay (a trade off between drag and cooling). I plan to use maskable ducts in the front bumper corners to duct air to specific locations as necessary
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