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Alpine R8 GT Turbo Too?

The good news. I had the exhaust manifold resurfaced and fitted a new gasket. No more ticking and smoking. I did some road testing and got max boost of almost 9 psi with a 10 psi wastegate actuator. The AFR didn't drop below 11 under ful boost. So the carb jet changes worked.

The bad news: The clutch slips sometimes in 3-5 gears when I go full throttle. In one occurance I was driving about 40 mph in 3rd gear and floored the throttle. The engine revved imediately bu the car didn't accelerate. This had happened before but I wasn't sure what was going on. I'm sure of it now. I checked the clutch free-play and it's OK. The clutch cover and disk are relatively new.

So does anyone know of a stiffer-than-stock cover for a 180mm unit? Maybe one from an R5 Alpine turbo?
 
The Clutch is a bit marginal, but I thought it would be ok at that output. The Gordini/ Alpine turbo uses the same clutch, though there is a 190mm one listed. It's definitely fully clearing?? How does the pedal feel? I wonder if there's a set up height issue lowering the clamping force.
 
But what did it max out at?

Ideally you should also be listening for det as well. AFR is only part of the picture.
The AFR during cruise was in the 14-16 range for a 5 minute drive, probably too lean? I need to take a longer drive to get better data.

I haven't heard any knocks or seen any on my knock sensor.

The Clutch is a bit marginal, but I thought it would be ok at that output. The Gordini/ Alpine turbo uses the same clutch, though there is a 190mm one listed. It's definitely fully clearing?? How does the pedal feel? I wonder if there's a set up height issue lowering the clamping force.
I got under the car and found there was almost no free-play in the throw-out arm. I adjusted the cable to give 3-4 mm of free-play. There was less slip in a subsequent drive but it was still slipping some.

I found a 190 mm clutch cover on the web also. Would it fit?
 
The AFR during cruise was in the 14-16 range for a 5 minute drive, probably too lean? I need to take a longer drive to get better data.

I haven't heard any knocks or seen any on my knock sensor.


I got under the car and found there was almost no free-play in the throw-out arm. I adjusted the cable to give 3-4 mm of free-play. There was less slip in a subsequent drive but it was still slipping some.

I found a 190 mm clutch cover on the web also. Would it fit?
I don't know for sure. Every turbo motor I stripped actually had a 180 mm clutch fitted. Set up height is important. if it's out by more than 0.5mm or 20 thou, you can be in trouble. That's why it's usually best to use a matching set of parts. Mixing and matching can be a bit of a lottery. Sorry I can't be more specific.
 
I don't understand what you mean by set up height. Can you elaborate?

I'm thinking of reducing the wastegate actuator to 7psi from 10 as a temporary way to limit clutch slip. Or maybe limit the accelerator travel a bit.
 
I don't know for sure. Every turbo motor I stripped actually had a 180 mm clutch fitted.

I found a shop in the use the will a build a custom clutch cover with increased pressure for a Renault Alliance 2.0 which I think has the same clutch as MK2 R5 in th UK. I need to dig through my records to see exactly what cover is in my car.
 
Set up height is set by manufacturer, it is not really adjustable. Each pressure plate is designed with a set thickness of friction plate, to get the correct set up height. You can mess around with machining flywheels or packing the pressure plate with shim washers 10 thou thick. Awkward and with limited chance of success.
Beware of uprating the pressure plate too much. The release mechanism is also a bit marginal.
 
Set up height is set by manufacturer, it is not really adjustable. Each pressure plate is designed with a set thickness of friction plate, to get the correct set up height. You can mess around with machining flywheels or packing the pressure plate with shim washers 10 thou thick. Awkward and with limited chance of success.
Beware of uprating the pressure plate too much. The release mechanism is also a bit marginal.
Thanks for the explanation.

The pressure plate and disc in my car were bought as a kit for a Renault Lecar. Pressure plates for sale on the web for an R5 Mk2 look identical to mine.

The custom part I am considering is avaliable in stages 1/2/3 with torque ratings of 144/170/190 ft-lbs. The interweb says peak torque for the R5GTT is 120. So the stage 1 should be sufficient. And not too stressful on the release mechanism. It's a little pricy but probably worth it.

Thanks much Steve.
 
Thanks for the explanation.

The pressure plate and disc in my car were bought as a kit for a Renault Lecar. Pressure plates for sale on the web for an R5 Mk2 look identical to mine.

The custom part I am considering is avaliable in stages 1/2/3 with torque ratings of 144/170/190 ft-lbs. The interweb says peak torque for the R5GTT is 120. So the stage 1 should be sufficient. And not too stressful on the release mechanism. It's a little pricy but probably worth it.

Thanks much Steve.
5Gtt has a 200 mm clutch which won't fit on a MK1 flywheel. Mk 2 flywheel won't fit in the R8 bellhousing without modification and then there is the starter to sort out. It's all do able, but can be tricky. A good 189 clutch should work ok
 
Time for an update. I reduced the preload on the wastegate actuator to give 7 psi boost instead of 10. I also adjusted the 1st and 2nd stage enrichment jets to 1.1 mm.
Now the clutch doesn't slip and the AFR drops to 10.5-11.5 under full boost which is 4psi in 2ng gear and 3 psi in 3rd. The AFR is in the 13.5-14.5 range during cruise. And, most imrportantly, the car is fun to drive! The car accelerates briskly in 2nd and 3rd. And can climb hills in third gear at 3000 rpm instead of screaming at 4500 in 2nd like it did with the R5 Alpine motor. Torque is a wonderful thing.

I'm still running the stock R5 GTT ignition map with no knocking. I suppose I could advance the timing and get more power, but I don't feel the need at this point.

I still plan to update the clutch at a later date and up the boost closer to 10psi.

So for now (with crossed fingers) I'd call this foray into the world of turbocharging a success. Thanks again to all of you who helped and encouraged my along the way. 200.gif
 
Nice one. It does make an excellent road conversion and is a pretty quick car fullstop. If you can get it up to about 150bhp it should be a good wind up on the road without straying into unreliability. There will be guys on here that will say the safe limit is a fair bit higher (and it probably is ) but the car is close to 100 kg lighter than a 5 and handles a shitload better, so it's press and steer....
Enjoy.. If you weren't before, you are now a member of a true Minority group......
 
I added a sensor to measure intake air temperature. I did a test drive with a few acceleration runs and the peak temperature was near 150F (65C). The outside temperature was 75F (24C). Max boost is 3-4 psi. Is the intake temp too high? I want to eventually up the boost to 7-8 psi.

Is the intake temperature too high?

I built a baffle to get more cool air to the air filter. It had no effect on inlet temperature. (See the photo) The intercooler is not in an ideal location, sandwiched between the radiator and the rear body panel (bottom right in the picture). This is the only "convenient" location to mount the intercooler. I'm thinking about adding a deflector on top of the intercooler to help flow more air through it.

Any ideas?

IMG_0682s.webp
 
65deg iat is pretty bad at low boost, you want it around 5-10deg above ambient.

Id start with changing your current intercooler for a larger bar and plate core.
 
If you swap the TDC ignition wires to the R5 AEI you get 4 deg advance.
I'd consider water injection to lower your intake temps. Either pre-turbo ( everyone's favourite talking point) or after intercooler. Or a charge cooler , with more efficiently places pre-rads.
 
65deg iat is pretty bad at low boost, you want it around 5-10deg above ambient.

Id start with changing your current intercooler for a larger bar and plate core.
I've been thinking about a better location for the intercooler, but there's no easy solution with a rear engine layout.

If you swap the TDC ignition wires to the R5 AEI you get 4 deg advance.
I'd consider water injection to lower your intake temps. Either pre-turbo ( everyone's favourite talking point) or after intercooler. Or a charge cooler , with more efficiently places pre-rads.
I might consider water injectioon as a last resort. I want to keep things as simple as possible.

Do you have any ducting on the front the channel the air?
No ducting. The car doesn't have a center or rear undertray which I think the cars had from the factory. They would help exhaust the hot air from the engine bay possibly?
 
Are you running the standard fan and shroud. Would be worth shutting off down the sides of the rad/ intercooler. Trying to force as much air through the intercooler and rad as possible. It's like a beetle, it's important that the air can't get from one side of the panel to the other other than through the intercooler and rad
 
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