Alpine R8 GT Turbo Too?

[BobG]

I've heard it said that "idle hands are the devils workshop." Now that I have my R8 Alpine running and handling great, all I need is more power. Steve Swan's great restoration of Paul E's R8 GTT has me longing for a turbo motor. The interweb says that Paul's GTT motor should produce 120 ft-lbs of torque. My atmo Alpine motor produced about 80 ft-lbs on a dyno. So how about a bespoke turbo motor using a C3J 1.4 liter block, a turbo 2 crossflow head, custom manifolds and Megasquirt or GTT ignition module? I can't use a GTT head and manifolds since I have no room for the turbo in front of the motor because of the gas tank. I have a wedge head atmo motor and a crossflow head (see the photo). I posted this photo of the head a while ago and consensus was that it was from a Turbo 2. Without the squish ramp it should be good for lower compression with appropriate pistons. I would need new cam followers and pushrods since the motor I would be converting is an atmo wedge head. Would the stock atmo cam work with a turbo? I'm not looking for huge power. Now I'll sit back and wait for the best minds in Renault turbo world to weigh in.
Bob G

 

[sparkie]

The stock atmo cam was a good upgrade for the turbo motors back in the day. Also, isn't the C3J 1390cc, which means you'd have to fit 1397cc pistons & liners to get the compression you want (not just pistons).

 

[BobG]

The C3J is 1397cc just like the C1J. It was the base engine for the US Alliance (R9) and Encore (R11). It had Renix throttle body injection. I have no idea if the atmo R5 had the same cam profile. Thanks for the info.

 

[BobG]

Does anyone know if the R5GTT flywheel is the same as the in the R11 atmo motor?

 

[Big Steve - Raider]

Does anyone know if the R5GTT flywheel is the same as the in the R11 atmo motor?

I imagine the flywheel would essentially be the same, it’s just the trigger pattern on the edge of ot that may be different..?

 

[Duncan Grier]

Not looked for sooo many years but 44x2 x2 rings a bell for older renault stuff

I am also getting older so could be very wrong

 

[Steve Swan]

Basically Yes it is all do-able.
Choices are
1.Use a GT turbo motor and make your own exhaust manifold There is enough room........... Then you can follow the tried and tested routes to Destruction.............
2. (i) Drop the compression on your atmo and (ii) make your own exhaust manifold to take a turbo use a 5Gordini/alpine/ Alp/Gordini turbo inlet manifold modified to take a throttle body and injectors.........
3. Build up another motor and follow step (ii) above........... Plough your own furrow to destruction......................
All have their pro's and con's
The R8/10 Bellhousing needs opened up a couple of MM to take the gt turbo flywheel as it is a smidge bigger
You can use a R5 Gordini turbo flywheel to save this issue, but the Renix trigger may not be good for modern aftermarket ECU.
@paule78 and I are working on a Flywheel for his phase 2 mods. TTV in the UK will make whatever you want, I'm trying to get it so that it all works and improves the clutch.
I am no expert on turbos or ECU's being firmly stuck in the past, But can answer any specific questions about what fits and what doesn't if you have them.
Flywheel, clutch and starter All pose issues, but I think I have a fix for all combinations. Paul's 8 had the original bellhousing modified to take the GTT starter, but the Clutch mech is struggling with an uprated 200 mm clutch, so we are going back to a 180mm with the centres moved about on the 200 flywheel
If starting from scratch I would use the Standard smaller flywheel from a MK1 5A or G with a trigger to suit or on the crank pulley, then you have covered the installation issues without having to chop anything up..
Modern turbo technology does not need such low compressions as was in the past. Problem with that head is that having the ramp machined out of it will make it more likely to detonate (the ramp was a lean burn anti-det idea ) it does not need the ramp if you want to rev it to 9000 rpm, but is much better with than without. It is all to do with squish and promoting turbulence in the chamber at lower rpm which allows weaker mixtures without Det. Like Amedee's masked spark plug idea which started the flame front in 2 different directions (like a twin plug)
One thing about all that mid range torque is that even with a big box it feels short geared and it could pull another gear, but No. I'm not making a 6 speed............................

la préparation de piéces de compétition / leurs avantages et leurs fonstions/ vue et réalisé par Jean-Marc ALBERT

This guy is the most Hardcore nutcase I have seen. He does not talk about money, I guess because if you have to ask you can't afford it .. Set aside a Half day to check it out...

 

[mrdini]

The C3J is 1397cc just like the C1J. It was the base engine for the US Alliance (R9) and Encore (R11). It had Renix throttle body injection. I have no idea if the atmo R5 had the same cam profile. Thanks for the info.

C3j are 1390cc unless there's more than one type?
Would working with the atmo not appeal,, 1550 cc upgrade car on another group makes 150hp on webbers with standard g head and I think cam re profile,

Still in keeping with r8g fans may hold better its value and cost a lot less

 

[BobG]

Basically Yes it is all do-able.
Choices are
1.Use a GT turbo motor and make your own exhaust manifold There is enough room........... Then you can follow the tried and tested routes to Destruction.............
2. (i) Drop the compression on your atmo and (ii) make your own exhaust manifold to take a turbo use a 5Gordini/alpine/ Alp/Gordini turbo inlet manifold modified to take a throttle body and injectors.........
3. Build up another motor and follow step (ii) above........... Plough your own furrow to destruction......................
All have their pro's and con's
The R8/10 Bellhousing needs opened up a couple of MM to take the gt turbo flywheel as it is a smidge bigger
You can use a R5 Gordini turbo flywheel to save this issue, but the Renix trigger may not be good for modern aftermarket ECU.
@paule78 and I are working on a Flywheel for his phase 2 mods. TTV in the UK will make whatever you want, I'm trying to get it so that it all works and improves the clutch.
I am no expert on turbos or ECU's being firmly stuck in the past, But can answer any specific questions about what fits and what doesn't if you have them.
Flywheel, clutch and starter All pose issues, but I think I have a fix for all combinations. Paul's 8 had the original bellhousing modified to take the GTT starter, but the Clutch mech is struggling with an uprated 200 mm clutch, so we are going back to a 180mm with the centres moved about on the 200 flywheel
If starting from scratch I would use the Standard smaller flywheel from a MK1 5A or G with a trigger to suit or on the crank pulley, then you have covered the installation issues without having to chop anything up..
Modern turbo technology does not need such low compressions as was in the past. Problem with that head is that having the ramp machined out of it will make it more likely to detonate (the ramp was a lean burn anti-det idea ) it does not need the ramp if you want to rev it to 9000 rpm, but is much better with than without. It is all to do with squish and promoting turbulence in the chamber at lower rpm which allows weaker mixtures without Det. Like Amedee's masked spark plug idea which started the flame front in 2 different directions (like a twin plug)
One thing about all that mid range torque is that even with a big box it feels short geared and it could pull another gear, but No. I'm not making a 6 speed............................

la préparation de piéces de compétition / leurs avantages et leurs fonstions/ vue et réalisé par Jean-Marc ALBERT

This guy is the most Hardcore nutcase I have seen. He does not talk about money, I guess because if you have to ask you can't afford it .. Set aside a Half day to check it out...

So many paths to destruction... Using the squishless Turbo 2 head is looking less attractive. How about using a stock C3J wedge head? This eliminates the need for new lifters, pushrods and maybe the cam. My research says the GTT head is similar but with more volume and lower compression. Is 9:1 compression too high? An R5 flywheel is non-existant in the Renault desert known as the USA; some type of trigger wheel on the crank pulley is a better option. Then I can use the existing flywheel, starter and clutch. And I want to use a carb with the stock manifold for simplicity if possible.
Thanks Steve.

 

[BobG]

C3j are 1390cc unless there's more than one type?
Would working with the atmo not appeal,, 1550 cc upgrade car on another group makes 150hp on webbers with standard g head and I think cam re profile,

Still in keeping with r8g fans may hold better its value and cost a lot less

The US spec C3J is 76mm x 77mm which computes to 1397cc. Maybe the UK spec model is different.
I bigger motor is a definite option, but I've always wanted to build a turbo motor.

 

[Steve Swan]

If you Go C1J 5GT Turbo Route, there is plenty parts around, going with the crossflow head means you need to get the thinking cap on for some parts, the crossflow head will make better power, as it is a better design, but you won't be exploring the upper reaches of what is possible with either motor, as it could tie the driveline and chassis in knots.
The turbo motor is Stealth quiet and has midrange torque no atmo can make, it is a nice conversion for road driving, making the car easy to live with and pretty quick too.
The standard 5G clutch is rated at 125lbs/ft about the same as a Std Turbo motor, so there is a potential issue there. The mechanism can't take large loads, so it is a compromise area.
Good fun though.........

 

[DaveL485]

Not looked for sooo many years but 44x2 x2 rings a bell for older renault stuff

I am also getting older so could be very wrong

I always called it "[19]-[miss one]-[big one]-[19]-[miss one]-[big one]" lol

 

[BobG]

After some thought and adding up potential parts costs, I'm leaning toward "C1J 5GT Turbo Route." I'd use the C3J motor I have with modified manifolds. I found a Solex 32 carb and manifold in my parts collection. And I previouly fabricated adaptors to fit the manifold to the C3J head.



I also have a header that can be modified for a turbo flange.

The first thing I need a turbocharger. The interweb says the R5 GTT used a Garrett T2 turbo. This model doesn't seem to be available anymore. What currently available unit would be equivalent?

 

[Steve Swan]

You will need to source a R5 GT Turbo carb, as it is designed to work under positive pressure. Ordinary carbs are not..
I hope someone with more Turbo knowledge than me will chip in with some items for the shopping list.
I take it the GT Turbo was never sold in the USA

 

[BobG]

I also have an R9/11 FI throttle body and manifold. That would require using a Megasquirt for fuel mapping in addition to ignition.
The only R5 sold in this country was the atmo Lecar.

 

[DaveL485]

The carb you need is a Solex 32DIS.

 

[BobG]

The carb you need is a Solex 32DIS.

Thanks. Can you recommend an available turbocharger?

 

[mrdini]

Thanks. Can you recommend an available turbocharger?

The Alliance inlet manifold , would that be the r9/11 type you have ,,,
If you have the space for it , it's a popular upgrade to fuel inject gt turbos and easier to find for you, although with the possible power limitations on an 8 the carb will most likely be fine and a easier route

 

[BobG]

Yes the Alliance and R9/11 have the same intake manifold based on what I find on the interweb.
I'd like to use a carb for simpicity. I want to avoid fuel mapping om an aftermarket ECU if possible.

 

[mrdini]

Yes the Alliance and R9/11 have the same intake manifold based on what I find on the interweb.
I'd like to use a carb for simpicity. I want to avoid fuel mapping om an aftermarket ECU if possible.

UK 9 / 11 didn't have fuel injection only carb on turbo models, only alliance , I don't blame you for simplicity