SEAT Ibiza - rwd turbo
Discussion
t I've seen in a while!
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
Max_Torque said:
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)
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
Max, can you explain the advantages in using split radiator and intercooling as opposed to running a full hight rad with the intercooler mounted low down. Especially when it restricts evac of the rad cooling air as you mentioned above.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
chuntington101 said:
Max_Torque said:
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)
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
Max, can you explain the advantages in using split radiator and intercooling as opposed to running a full hight rad with the intercooler mounted low down. Especially when it restricts evac of the rad cooling air as you mentioned above.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
Added to which, the main water radiator is heavy (it's full of water!) so mounting it low and the much lighter I/C rad high is sensible. By steeply angling the main water rad, the overall package height is also reduced and you can get some benefits from non forced convection cooling at low vehicle speeds (typical of UK stage rallying). As a radiator only requires something like 50-60% of it's core area as intake area (because the core itself reduces the flow area, and it uses highly turbulent flow to get good heat transfer) by tilting the main rad, and packaging the IC rad above it both rads get a nice cool air flow close to ambient temp (rather than have them sandwiched and the rear rad gets hot(ter) air)
The exit area is more than sufficient for both radiators, it's just a question of subjugation to avoid upheat at low speeds!
It's really noticeable with this cooling layout, that with the vehicle not moving, the cooling rad fans hardly even cut in at idle. In effect, there is enough convection driven cooling to remove the engines idle heat flux without cooling fans.
Transmission!
Probably the Achilles heal of more high power cars than any other part! Expensive and tricky to make durable and often neglected compared to the engine. Power is cheap these days, leveraging that power into useful tractive effort isn't!
So, a quaife 6spd sequential dog box, mounted at the rear of the car, receiving drive via a CTG carbon engine speed prop housed in a carbon/alluminum torque tube, and passing drive out to a BMW E46 M3 "M" differential, with the GKN speed sensitive cross axle clutch/locking system.
Required significant floor pan mods to fit (as you might immagine) but moves something like 100kg of drivetrain backwards in the car a long way to aid traction, and provide a higher polar moment of inertia for stability.
Torque tube and bell hounsings, with trial ally "propshaft" for dimensional conformation:
The real deal, CTG prop:
Assembled with ex Volvo (suprisingly nice die cast and lightweight!) bellhousing:
Concentric clutch actuation:
Transmission rear installation, squeezed between fuel tank bay and exhaust line:
Gearbox with mounts and adaptor housings:
As installed:
Driving out via a cush coupling to allow for any misalignment and provide a degree of torsional damping, into the nose of the M diff (large disc is "mech handbrake" for MOT!):
All my Gears in a line:
Manual (backup) shifter lever (strain gauged for "flatshifting" torque cut) sits on carbon centre tunnel assembly (also holds power distribution and some driver interface switch stuff). Carbon shift rod obviously heads rearwards into a modified shift mech sat on top of the gearbox:
Designed my own pneumatic paddleshift system and controller. Uses a 10bar airpump and small carbon resevoir as a pressure store, via 12v 3 port solenoids to activate a pneumatic cylinder that pushes / pulls for the appopriate gear:
Gear requests via a single carbon paddle mounted on the steering column, pull for up, push away for down. Better than steering wheel paddles for a car in which a lot of wheel twirling may occur (as the driver always knows where it is):
Uses hall effect switches and magnetic triggering for reliability:
Air pressure pump mounted low behind passenger seat:
Probably the Achilles heal of more high power cars than any other part! Expensive and tricky to make durable and often neglected compared to the engine. Power is cheap these days, leveraging that power into useful tractive effort isn't!
So, a quaife 6spd sequential dog box, mounted at the rear of the car, receiving drive via a CTG carbon engine speed prop housed in a carbon/alluminum torque tube, and passing drive out to a BMW E46 M3 "M" differential, with the GKN speed sensitive cross axle clutch/locking system.
Required significant floor pan mods to fit (as you might immagine) but moves something like 100kg of drivetrain backwards in the car a long way to aid traction, and provide a higher polar moment of inertia for stability.
Torque tube and bell hounsings, with trial ally "propshaft" for dimensional conformation:
The real deal, CTG prop:
Assembled with ex Volvo (suprisingly nice die cast and lightweight!) bellhousing:
Concentric clutch actuation:
Transmission rear installation, squeezed between fuel tank bay and exhaust line:
Gearbox with mounts and adaptor housings:
As installed:
Driving out via a cush coupling to allow for any misalignment and provide a degree of torsional damping, into the nose of the M diff (large disc is "mech handbrake" for MOT!):
All my Gears in a line:
Manual (backup) shifter lever (strain gauged for "flatshifting" torque cut) sits on carbon centre tunnel assembly (also holds power distribution and some driver interface switch stuff). Carbon shift rod obviously heads rearwards into a modified shift mech sat on top of the gearbox:
Designed my own pneumatic paddleshift system and controller. Uses a 10bar airpump and small carbon resevoir as a pressure store, via 12v 3 port solenoids to activate a pneumatic cylinder that pushes / pulls for the appopriate gear:
Gear requests via a single carbon paddle mounted on the steering column, pull for up, push away for down. Better than steering wheel paddles for a car in which a lot of wheel twirling may occur (as the driver always knows where it is):
Uses hall effect switches and magnetic triggering for reliability:
Air pressure pump mounted low behind passenger seat:
200bhp said:
Any estimates for power and torque?
TBH, i have deliberately steered clear of talking about power, because there is so much bull and general rubbish talked around the subject. However, the engine design work and component specification (Pmax, BMEP, Turbo sizing, IC efficency, DCR, Cam specification and timing) have been done with a target boost pressure of 3.6bar(abs) @ 7200rpm. If you apply a typical BSAC figure, you would expect to get a flywheel power output in the high 5's / low 6's.Peak torque will be capped for driveability reasons, but again the engine mechanics should be good for 35bar BMEP, which is around 650Nm.
Enough to be getting on with i think....... ;-)
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