3l GTV6 PRC project

redalfaracing · April 28, 2009, 05:41:55 PM

Been playing with the front brakes this arvo, some one will probably know the answer to this question. Which alfa 5 stud 15 inch rims have the most clearance for big brakes. The speedline rims i have been running on the sedan ( originally from an Alfa 90) have way more clearance than the benzoni rims that come on the GTV6, and it's almost enough to fit the 305 mm discs with the superlite calipers, but not quite! Anyone been thru this b4? rather not have to shell out for compomotives.

redalfaracing · April 29, 2009, 07:55:09 PM

it would seem the cheapest/easiest option is to convert to 100 PCD and fit subaru rims. There are any number of s/h compomotive or oz rally rims floating around. some look like man hole covers, but at the end of the day, they are strong and they fit big brakes. converting front is just a matter of drilling 5 new holes in hubs and discs. rear can be done by drilling bigger holes offset and making stepped studs. Fiddly but cheaper than "new" rims or making new shafts with flanges.

alfagtv152 · April 30, 2009, 02:03:01 PM

Hi Greg,
Sounds a good way to go if you dont have to stick to Alfa wheels.I cant resist!-there is no point in reinventing the wheel if there are already plenty A-round!.
Cheers
Andrew

redalfaracing · April 30, 2009, 04:31:05 PM

I took my big brakes to my mate Toms place today. He Rallys a Subaru Imprezza on Compomotive wheels. The 305 mm 147 GTA discs and wilwood superlites fit easily inside the 6 x 15 rims. The answer is simple. just make it 100 PCD and find a set of compomotives.

redalfaracing · May 14, 2009, 02:23:09 PM

my new rear calipers arrived today from the States, Wilwood IR-GT 4R 's Nice bit of work. The radial mount brackets wont marry up with the Gearbox mounts, but a beefy bit of aluminium angle should easily do the trick. Not much else has happened lately ( bloody work keeps getting in the way)

redalfaracing · June 07, 2009, 03:32:36 PM

have some pics of car as it stands at the moment. painted the inside this week and it's ready to fit seats,dash,battery and side glass. Took sooo long to move the tank and fit a fire wall around it. But done now and i am pretty happy with the result. Still in the midst of building the pedal box and hydraulic handbrake. Get them finished this week and installed. Might be about time to pull the gearbox out and see what i can do about gear ratios etc. I am assuming that it is a 4.1:1 ratio diff. That will be ok. I have a spare twin spark gear set to play with. like some feed back on what you guys think is the best 3rd 4th & 5th for a V6. Bearing in mind top speed is not an issue. be happy if it does 180 klicks.

Mat Francis · June 07, 2009, 03:50:08 PM

Looking awesome Greg.

Love these updates.

Jekyll and Hyde · June 07, 2009, 09:58:39 PM

Quote from: redalfaracing on June 07, 2009, 03:32:36 PM
have some pics of car as it stands at the moment. painted the inside this week and it's ready to fit seats,dash,battery and side glass. Took sooo long to move the tank and fit a fire wall around it. But done now and i am pretty happy with the result. Still in the midst of building the pedal box and hydraulic handbrake. Get them finished this week and installed. Might be about time to pull the gearbox out and see what i can do about gear ratios etc. I am assuming that it is a 4.1:1 ratio diff. That will be ok. I have a spare twin spark gear set to play with. like some feed back on what you guys think is the best 3rd 4th & 5th for a V6. Bearing in mind top speed is not an issue. be happy if it does 180 klicks.

With top speed not an issue, I'd be looking to find a 4.3 final drive, and talk to Hugh at Alfpa Repairs/Monza motors about putting together a close ratio gearset for you. With such a gearbox, and standard tyre diameter, I was hitting 180km/h no issue at all at Sandown in 4th gear. Admittedly my motor is revlimited to 7,500, where yours may be limited a bit lower, but I was doing roughly 6,800rpm at 180, and I believe in 5th it was somewhere between 5,000 and 5,500 (only used 5th on a practice lap or two, then realised I wasn't going fast enough to need it!). Obviously if you are running bigger than standard tyres (I can't remember if you've said) you'll be doing less revs for a given speed, and the extra acceleration of the lower diff ratio would be useful to cancel out some of the weight/gearing effect of the larger tyres - as well as those moments in a rally when you find you've picked too high a gear for the corner....

redalfaracing · June 08, 2009, 08:35:07 AM

i have a box with a 4.3:1 diff ratio. 2.875, 1.72, 1.35, 1.13, .946 which works brilliantly in the 2 litre. I am reliably informed that a worked v6 will eventually screw the 4.3:1 pinion gear off the end of the shaft.
I may be tempted to run it with the standard 2.5 but not a modified 3 litre given the trouble i went to to get this one ( bought it from a guy in amsterdam ) maybe i should strip that box down and slot those ratios into the 4.1:1 box and see what happens?

not really wanting to hijack my own thread but i just found a pic of the alfetta in a high speed 4 wheel slide.

Jekyll and Hyde · June 08, 2009, 12:24:50 PM

Quote from: redalfaracing on June 08, 2009, 08:35:07 AM
i have a box with a 4.3:1 diff ratio. 2.875, 1.72, 1.35, 1.13, .946 which works brilliantly in the 2 litre. I am reliably informed that a worked v6 will eventually screw the 4.3:1 pinion gear off the end of the shaft.
I may be tempted to run it with the standard 2.5 but not a modified 3 litre given the trouble i went to to get this one ( bought it from a guy in amsterdam ) maybe i should strip that box down and slot those ratios into the 4.1:1 box and see what happens?

not really wanting to hijack my own thread but i just found a pic of the alfetta in a high speed 4 wheel slide.

If you are doing gravel rallies and not tarmac events, I should think the 4.3 would last perfectly fine, as it won't get the huge torque loadings that can be achieved on a sealed surface. That said, there are a few pretty hot V6 cars going around running 4.3s for circuit work, and they do last very well. And to be honest, you can have the same failure with the standard v6 pinion... 4.3 crownwheel pinion sets are getting a little rare but definitely not yet unobtainable in Australia, if that is the part you are most worried about, track yourself down a spare set to keep in the garage, then run the complete gearbox in the 3.0 litre!

Its generally not as straightforward as just swapping gearsets around between boxes, you need to get the shims set up correctly, and sometimes some machining is required to make it all work, so keep that in mind before you start trying to mix and match internals. The shim setup from inside one casing and on one pinion may not work at all in another casing/on another pinion shaft.....

In other thoughts, that's an impressive 5th gear ratio - one that you'd almost expect to see in a modern six speed gearbox! Using the gear ratio calculator off here http://www.spannerfodder.com/the_works_escorts-ratios.php that would see you doing 6,200rpm to hit 180km/h with a standard size tyre.

redalfaracing · June 08, 2009, 10:03:29 PM

Quote from: Jekyll and Hyde on June 08, 2009, 12:24:50 PM
In other thoughts, that's an impressive 5th gear ratio - one that you'd almost expect to see in a modern six speed gearbox!

.946 is actually 4th gear from an Alfa 90. when i was building my 2 litre box i doubted very much that i would have the mumbo to pull a .83 5th, so i grafted the .946 to make it a 5th. works a treat!

redalfaracing · June 19, 2009, 06:17:38 PM

Does anyone know if i can get just the float of the fuel level sender for the GTV6 tank? A good s/h one would be ok. mine is half full of fuel. guess it will read wrong.

redalfaracing · July 21, 2009, 08:54:26 PM

an update of the project. Not a lot has happened. Been putting in a lot of reverse cycle split systems though. But, i am having this week off to work on it ( and the new SPAM )
In the last month i have fiddled with the seats, removed all the wiring, and made the pedal box. Finished that today. Pretty happy with the result. Made a new pedal box, used the original pedals with modifications fitted a balance bar, changed the pedal ratio to 6:1 for the brake and the clutch ( lighten the clutch action ). Well have a look and see what you think.
Been making a new loom to marry up with the Haltech engine loom, boy that takes a fair bit of thinking! makes my head hurt. When i pulled the old fuse box out it was a bit melted, lucky the thing still ran.

Still looking for a fuel sender float.

Sheldon McIntosh · July 21, 2009, 10:04:25 PM

Nice work, can't wait to see this car. I'm guessing it won't be at Motorkhana this weekend though?

redalfaracing · July 22, 2009, 08:36:59 PM

not a chance Sheldon. be at least a couple of months till it is ready to go. i'm a bit time chalanged at the moment. Work, Home reno's, and now planning for PAC's round of the VCRS, the Yakkerboo Trial is in full swing. I am the Clerk of Course and i have to find a few hundred hours between now and Nov 28th. And it comes out of the motorsport allocation of time you know!
Does any one have a spare 90 steering wheel lying around? the momo boss is a great thing to use. not sure i like the GTV6 boss, and it is welded onto the wheel which i want to change anyway. i used a 90 boss on the alfetta rally car and it works well. i am using a 90 column with a concoction of joints and shafts off other cars to move the wheel 60 mm rearward to get a relationship with the pedals that i can live with. Plus i gotta get rid of that ugly rubber joint ( which weighs a ton) just above the rack.