Fiat Coupe race car Discussion thread

Hey nice project, what have you got the weight down to out of interest?

Davie

No Idea! I have fiberglass doors and a boot lid being made too at the moment, after that we are going to weigh her!

Looking good Liam. Keep us posted on your progress please.

The big debate in the workshop at the moment is the gearing, I know that the 6 speed coupe 'box and the V6 alfa boxes are very similar in that the innards are interchangeable, however no one seems to know what the story is with the 5 speed, my gut tells me its a very similar 'box to my 2.4 JTD 156, in which case the Q2 diff will fit and the final drive from the 2.5 V6 will fit.

If I can get that to work, (with the viscodrive in the bin outside) I will nave reduced my top speed to something like 120mph, but should really help improve my acceleration

I am not that up on gearbox's etc. But to limit top speed to 120mph!! Then whats the point of trying to acheive 300hp?
I was on track 2 weeks ago in my standard road coupe 2 up and touched 130mph on the back straight.
I understand the need for acceleration Liam,but it seems your looking at a massive top speed loss.
Someone with more know how should be along soon to give a better view hopefully.

There is one huge reason for the sacrifice in top end speed
and thats this:


Mondello park, the only circuit we have in Rep of Ireland very tight very technical, the most powerful car in last years ITCC was a 500+bhp Sierra Cosworth RS500 and the quickest he got on the pit straight all year was 112mph, Martin in the RS500 actually won the Championship last year but he had some serious competition from far lesser powered cars with close ratio 'boxes

Yes i thought that may be your reasons Liam. This is my local track. http://www.circuit-valdevienne.fr/
I am aiming for 350hp with a pure track suspension/braking set up. I hope to get to maybe 150 on the back straight one day. But i will only be doing track days.
This track http://www.charade.fr/data/model.htm is fantastic,you would love it. We had a French Coupe club day there last August.

Check with sparco - he's done a bit of work and got a set of.ratios he's happy with - based on knockhill so no massive speeds either.

Liam I agree with your speed choice, just need enough front grip to put the power down as torque will be massive, I guess you'll know what tyres and rim widths you can use. Just need a tall first and close ratio after that.

Best move - the fibre glass bits, weight saving all the way!!

Best of luck

Yeah putting the power down will be the issue, I'm limited to 220mm slicks by class rules, I reckon a limited slip diff and welded up viscodrive could be on the cards pretty soon.

most of you will think I'm mad, but we are also looking at how we can integrate a selespeed unit.

Just a couple of observations...

Lowering the weight over the front wheels will decrease front end grip...

Widening tyres won't increase grip...

Shortening gear ratios on a 300bhp coop will end up leaving you on the downward turn chasing through the gears. Far better to have leggy gears if running a fast spooling, torque monster. You don't want to end up passed the peak power when changing up...

Lowering the weight up front will decrease the force that gravity exerts downwards on the tyres, yes. But it will also decrease the lateral forces in cornering, and its not as if the coupe is light up front to start with anyway.

At present I've taken 40kgs out of the front end and the differance it made to turn in to corners was huge, there is another 40+kgs to go soon with the wiring loom and abs system and a few other bits and pieces to go into the bin.

As for the gearing, it its worth trying, its very easy to return it to standard if it doesn't work

Sorry Trappy but everything you wrote is wrong and Liam has it covered.

Lowering front end weight doesnt decrease grip, it lowers the requirement for grip or increases the speed at which it is lost. A lighter car will corner faster then the heavy car due to the reduction in moment tryingto resist turning.

Wider tyres do increase grip, dont be confused with pressure exerted, with the right compound a larger contact patch will offer more grip.

As for gearing no, you go shorter ratio and lower final drive, the point of going to far is if you max it out on every stright long before the corner or it wheel spins every gear and goes no where. Aside from that ensuring the maximum acceleration is the goal and the spacing in road boxes and road FD's are too large and too high respectively.

Liam.Is it you thats running a straight through exhaust from the turbo ? If so do you know the Decibels its producing please ?
And do you or anyone else know if a straight through is safe for the engine/turbo ?

Liam,
this sounds like good fun! Good luck.. not a racer myself, but it would be fun if you could come to a track day in the UK once the beast is ready . Just like the Cheltenham Festival; an Irish invasion to steal the English crown jewels.

Where in Ireland are you based? I only know Cork and the peninsula down towards Clonakilty etc.

Tim

yeah its a 3" custom exhaust straight from the turbo to the rear end, no idea what db it is, its actually not that loud at all.




I'd love to bring it over sometime!

I'm based in Mullingar, right in the centre of the country.

It started last night, and ran (badly) for a bit before dying, nearly there now, just have to get it ticking over property before bringing it to get mapped on the rolling road. My aim is to get the car out for a track day in Mondello on the 25th of April

I started painting the bonnet, doors wings and bumper this evening, its very very green, I like it!

Loving that colour liam. I will get over and see the car in action next year. I am normally in Waterford area once or twice a year.

looks great how much weight do you think you have stripped out

Looking good Liam,another bumble bee. I did like the green though. How's she running ?

Liam where in Ireland are you based roughly

Mullingar mate, right in the centre!

Ok I was working in Dublin for a week, would have said Hi.

Looks great Liam nice to see someone else having a go at the racing lark with the trusty coupe. Well done mate most people don;t know how hard it is to get a coupe ready to race and hpw much effort and time it takes. Most of my bits have been made from scratch.

Liam again well done mate. I'll be watching with interest and if you need any info then i'll be happy to help.

Liam,
Did you get your fibreglass bootlid? If so was it any good and if so where can I get one? Marco, do you have a fibreglass bootlid? I'd like to lighten my race coupe for next year.
Ta
Jason

No i don't think it will save that much weight as they are not that heavy anyway. I also have a rear wing on and grp/carbon bootlids need to be made properly if they are to support a wing (that works and creates downforce that is!)

Good points, I hadn't actually weighed the boot lid but as you can't run a rear spoiler in the Classic Sports Car Club it was the next unstructural lump that I could target. I've got the weight down to 1190kg which for a road legal car with a full roll cage is probably quite good?

Yes it is. I'm sure we've had mine under the 1100 kg mark but i'll have to weigh it again before the beginning of the season and see where we are now.

Cheers guys,

I've been trying to find as much info as possible on your car and how its set up Sparco!!

I'm not stalking, I swear!

The car hasn't been touched in over 6 months, as I've been concentrating on getting my road going Coupe going again (blown engine) Its now running sweetly so the Yellow race car is gonig back into the workshop today, re the bootlid, I have the GRP bootlid sitting ready to bolt on, to be honest its only a few kgs lighter than standard to i dont know if its really worth the expence, I'm limited to 1000kgs for car and driver in my class and thats my aim!
The two doors are 40kgs each, the replacements are less than 10kgs!

Plank, I can get a price for you if you like? a mate of mine makes them for me, and the molds are made from my panels

1000 kgs only with car, driver and cage
car with all liquids / petrol ??
do you have to use a FIA tank?? do you have to have a minimum size ??

Interesting project btw

Yep, the regs are 1000kgs minimum with driver, ready to race. It can be done, the plasma cutter is my friend!!

Standard tank for the moment, will probably upgrade it during the year

Liam, I would be up for a set of lightweight doors also. So yes i am interested in a price from your pal.

I'll be talking to him next week, I will get a price for you

The issue of gearing has cropped up again, I can manage 98mph on the main straight in Mondello Park, which means that I never get to use 4th or 5th! The Honda's with their short gearing will eat me alive under acceleration even though I have nearly 100bhp more than some of them, Shorter gearing needed!!

Holy thread revival Batman!!

I've been away from home with work for the best part of a year now, and haven't done much work with any of my cars. Slowly but surely over the last wee while things have started to move again. Coupe is just home from mapping, 290bhp @ 1.2 bar. It's a little bit lazy, and needs 5 new coils and then she will run @ 1.4 bar.

She is booked in for a trackday on the 26th of the month.

The next job is applying some graphics, this is pretty much what we have in mind:

Interesting, invisible graphics/car, they'll never see you coming up the inside

Hmmm.... does it work now?

Nice

Im interested it the door

GRP door in the picture?
Skint but still interested to know the cost.
Keep up the good work!

Got more pics of the rest of the car?

More likely GRP bonnet

Standard doors in the pics, GRP bonnet, a set of GRP doors will set you back €500 euros.

Not a bad price, as a door can`t be easy to do in GRP!
I think what your car needs most is some yellow smiley dust caps.

LOL, not a bad idea!

Some photos of her in action recently









All tucked up for the winter

How did it perform on track?

It did very well, desperately needs a decent limited slip diff, and as I keep saying, the gearing is a too long. on the main straight in Mondello park I'm hitting 98-99mph just before the breaking point, and to be honest it's only just starting to get going at that stage.

The new Ferodo DS3000 brake pads were just awesome, like throwing an anchor out!

So, the car is in the workshop again, 15" wheels almost fitted, just waiting on 30mm spacers for the front wheels to help the rims clear the standard calipers. Also the newly built gearbox is almost ready to drop in. We have dropped the innards of a 2.5V6 Alfa 6 speed gearbox into the coupe 5 speed box casing, works a treat! gearing should be something like below:



This should make a massive difference, as I struggle to get out of third gear in Mondello park!

I bet thats fun to drive Liam. Good work going on.

It should be serious fun, next track day on the 7th march in Mondello park

We had the car out testing on Monday, to say that the new gearbox has made a difference is an understatement, it is a different car completely, the pull in third gear!!!

Thats good news Liam. Let us know how you do on the straight at Mondello please.

Any Video's Liam?

Good to see someone else messing with gearing etc to make differences. Ive messed with it for years on my BMW M3 drift competition car. got it down to nigh on perfect now.
140mph and it will hit the limiter but damn does it get there quick.