Alpine R8 GT Turbo Too?

[BobG]

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

Yep, standard fan and shroud. I copied the setup from your work on @paule78 's car. No significant gaps in the panel, except for the swiss-cheezed area above the air filter box. I'm going to plug the those holes and remove the baffle. It didn't help cool the intake air.

 

[Brigsy]

I've been thinking about a better location for the intercooler, but there's no easy solution with a rear engine layout.


I might consider water injectioon as a last resort. I want to keep things as simple as possible.


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?

Id say 50% of your current issue is the chinese tube and fin design, they are always crap.

Id go slightly larger bar and plate design in same location, which will probably bring it down to reasonable levels.

WI not great and another thing to break. Chargecooler always crap unless spending loads of dollar, and you need a pre rad etc so if space is a premium, hard to package.

 

[Duncan Grier]

Mid/rear engine layout a challenge with charge temps and the science of getting good airflow in/through/out

My experience is charge coolers work better in this setup than I/C but as Brisgy correctly points out cheap dont work.....same for I/C. But with CC you also need to add decent pre rad, header tank, pump etc and gets a lot more ££

While another thing to manage WI can work well but needs setting up correctly

 

[BobG]

Id say 50% of your current issue is the chinese tube and fin design, they are always crap.

Id go slightly larger bar and plate design in same location, which will probably bring it down to reasonable levels.

WI not great and another thing to break. Chargecooler always crap unless spending loads of dollar, and you need a pre rad etc so if space is a premium, hard to package.

Mid/rear engine layout a challenge with charge temps and the science of getting good airflow in/through/out

My experience is charge coolers work better in this setup than I/C but as Brisgy correctly points out cheap dont work.....same for I/C. But with CC you also need to add decent pre rad, header tank, pump etc and gets a lot more ££

While another thing to manage WI can work well but needs setting up correctly

Thanks for the info guys. I'll try to get more airflow through the intercooler for a first step.

 

[sparkie]

Just run it rich as fook. The extra fuel will aid cooling (joke).

 

[Turbell]

I thought the engine trays were an important part of the airflow on rear engines Renaults? Did you mention earlier yours are missing?
I'm uneducated on 8's , as 4cv/Daup have intakes forward of the rear wings , the radiator sitting on the gearbox, cowled in , high pressure in front of rad, low pressure bay with the fan running on the engine constantly pulling, engine cover (4cv) rear panel ( Daup) louvres creating low pressure drag.
8 I assume with no intakes, but low pressure at the the rear of the enclosed rad panel, assuming air goes over the engine cover vents 'pulls' on this area?...... Although then the mystery is if that is the case, why there's a ducted intake to the air filter that is in the rad panel?
The intake on my 4cv/750 , I've ducted to the side of the rad , in what I assume is a high pressure area, being front facing?
Does not having the engine bay trays make a mess of the air flow?

 

[andybond]

Does not having the engine bay trays make a mess of the air flow?

Absolutely!

Also makes the rear end act like a parachute.

 

[Steve Swan]

Never had engine trays, never had a problem, with rear tank or without, made no difference. If you have them use them, if not don't worry about them.

 

[BobG]

I did a road test a few weeks ago with the intercooler raised to the center of the radiator, hoping it would draw more air. The air temperature was in the upper 80's (F). The inlet air temp was still above 140F and the coolant temp was around 220F! Time for a new plan.

I decided to mount the intercooler in the cavity in front of the engine and behind the rear seat bulkhead where the fuel tank used to be. I fabricated an aluminum box around the intercooler and and mounted 2 electric fans to it angled downward.


I mounted the setup under the package shelf behind the rear seat. I had to cut two openings in the rear bulkhead for access.




This arrangement should draw air from under the car through the intercooler and exhaust it down and out under the car (in theory). Here are pics of the air pipes leading to and from the cooler.




I did another road test this afternoon with air temp at 75F. The inlet air temp stayed below 120F after a few acceleration runs with full boost. The coolant temp stayed below 190F. This testing was done with the two holes in the rear bulhead open and the rear body panel removed.

I was able to use the microsquirt to switch the fans on when the inlet temp exceeds 110F.

I'll make some covers for the holes and fit the rear panel in the next few days and run another test.

 

[Brigsy]

Inlet and coolant temps sound much better than before, good improvements. I guess airflow must be loads better in current place.

 

[BobG]

Bought a new pressure plate from Mecaparts with stronger clamping force. This should allow me to increase the boost without slipping the clutch. I installed the new part and set the free play, but I couldn't get the trans to shift into any gear. I checked the the gap between the pressure plate, disc, and flywheel with the pedal fully depressed. The was 1.5-2 mm gap between the disc and flywheel, but no gap between the disc and pressure plate. I turned the engine by hand and the disc would turn but was definitely rubbing on the pressure plate.

Any ideas on what is going on here?

 

[Steve Swan]

|Hmmmm. I had something similar once. If you have clearance between the flywheel and clutch friction plate, with the pedal pressed, Logic dictates that the friction plate could move on it's splines toward the flywheel to give some clearance between the friction plate and pressure plate. I always check the clutch clears at the earliest possible moment on re-assembly, as if it does not, fitting more parts won't fix it. I had one once that was only just clearing, so I carried on and couldn't get gears, with the motor running. I Pointed the car down the road engaged first gear (engine warmed up first) and turned the starter, it cured itself after a couple of operations and to this day, I am unclear about what caused the Drag.
Do not try this in an enclosed space............

 

[BobG]

|Hmmmm. I had something similar once. If you have clearance between the flywheel and clutch friction plate, with the pedal pressed, Logic dictates that the friction plate could move on it's splines toward the flywheel to give some clearance between the friction plate and pressure plate. I always check the clutch clears at the earliest possible moment on re-assembly, as if it does not, fitting more parts won't fix it. I had one once that was only just clearing, so I carried on and couldn't get gears, with the motor running. I Pointed the car down the road engaged first gear (engine warmed up first) and turned the starter, it cured itself after a couple of operations and to this day, I am unclear about what caused the Drag.
Do not try this in an enclosed space............

I was thinking that the disc might be jammed on the spline, but it that was the case the pressure plate would push the disc against the flywheel, right?
I also thought thhe pressure plate might be applying uneven pressure causing the disc to jam on the spline, but the gap between the disc and plate was the same all the way around so that's probably not the problem. I was able to gently slide a thin blade between the disc and plate but it was firmly stuck. Hmmmm indeed!

 

[Turbell]

This interests me, as ever since I swopped 750 box to a 318 four speed the clutch has never been as good, the 318 uses a fork arrangement, whilst the 314 was a cranked pivot.
Unless I have virtually no free play on the cable it's a bitch to get in gear, anything other than bang into the carpet and it snatches.
My point is I don't think the fork set up moves with as little effort as the crank, wonder your increase in pressure plate effort is causing flex anywhere ( I had to beef up the pedal end of the cable mount as I could see it flex on the floorpan when an assistant sat in the car and operated the clutch) I was wondering if a Dauphine Gordini, which my whole rear set up is had a greater pedal pivot, and whether lengthening the pedal end would give me greater travel?
This is a bit of a thread hijack, but my point is I changed box set up and had issues, you changed pressure plate and had same?
I've had previous issues where I had burrs on splines on friction plate and this has caused your issue, so always check they're nice and smooth on shaft.

 

[BobG]

This interests me, as ever since I swopped 750 box to a 318 four speed the clutch has never been as good, the 318 uses a fork arrangement, whilst the 314 was a cranked pivot.
Unless I have virtually no free play on the cable it's a bitch to get in gear, anything other than bang into the carpet and it snatches.
My point is I don't think the fork set up moves with as little effort as the crank, wonder your increase in pressure plate effort is causing flex anywhere ( I had to beef up the pedal end of the cable mount as I could see it flex on the floorpan when an assistant sat in the car and operated the clutch) I was wondering if a Dauphine Gordini, which my whole rear set up is had a greater pedal pivot, and whether lengthening the pedal end would give me greater travel?
This is a bit of a thread hijack, but my point is I changed box set up and had issues, you changed pressure plate and had same?
I've had previous issues where I had burrs on splines on friction plate and this has caused your issue, so always check they're nice and smooth on shaft.

I was expecting the new pressure plate might require more pedal/release mechanism travel. When I first experienced the dragging problem a started to look for ways to increase travel. But then I saw that I had enough gap between the flywheel and pressure plate and I knew lack of sufficeint travel was not the problem.

 

[Turbell]

Yep, you're right, I need to look into mine more in depth, been a while since I did it, lived with it TBH, used it very little last couple of years.
Trying to remember where I got to, I know there's quite a lot of slop on pedal pivot due to wear on the shaft, might remedy that first.
What I can remember is the more I had the clutch adjusted up ( to the point the release bearing would probably be sat on the pressure plate) the better the gear engagement was.
I did video the arm/cable movement with my phone whilst I depressed the clutch and it was pretty pants,
Another job on the list...

 

[Steve Swan]

Good point @Turbell . @BobG It may be flexing the floor at the bracket on the C crossmember where the clutch rod becomes a cable. A known problem area on any 8/10 well worth re-enforcing the floor at this point, if it is not already cracked.
Ryan. Any slop will have to be got rid of. My 8G ended up having a piece of plate welded to the pedal, so a new pivot point can be made. It worked well in the end. Sometimes we forget how long the journey to sort something out is.....

 

[BobG]

Clutch rod bracket is solid.

I removed the clutch assembly yesterday. Nothing looks out of the ordinary. No unusual wear marks. The disc slides freely on the splines. Here are photos of the old and new pressure plates, new one on the right and bottom.





I'm at a loss at this point.......

 

[Brigsy]

Maybe check the fingers on the pressure plate are not binding on the clutch plate centre as there is differences in design on both pressure plates.

Had a faulty paddle clutch plate with similar issues years ago, when clutch was fully depressed the fingers were touching the centre of the clutch plate and couldnt get gears, but raise the clutch 5mm off the deck and it worked. I fitted a pedal stop to save pulling the gearbox back off.

 

[BobG]

Maybe check the fingers on the pressure plate are not binding on the clutch plate centre as there is differences in design on both pressure plates.

Had a faulty paddle clutch plate with similar issues years ago, when clutch was fully depressed the fingers were touching the centre of the clutch plate and couldnt get gears, but raise the clutch 5mm off the deck and it worked. I fitted a pedal stop to save pulling the gearbox back off.

@Brigsy, I think you nailed it! Here's a photo of the disc hub looking through the pressure plate. You can see bite marks on the disc hub. So it looks like I had too much pedal travel and the fingers were grabbing the disc. I was thinking I would need more travel with a stiffer pressure plate, not less. Now I hope the clutch will release before the grabbing starts. I'm heading to the garage to bolt the motor to the bellhousing and reduce the pedal travel to test your theory.