ALFAGTV6.COM

[JohnGTA]

I need some feedback. I have 2 GTV6 3L's, the red one is stock standard & that I'm keeping that way, my white one though presently runs a Glenwood Motors big bore 3.5l.
I'm happy with the performance but after just finishing my 156GTA with big bore & turbo, well it's changed my perspective a little.
I have a brand new Alfa 75 3L box with the 3.5:1 ratio & LSD & initially I planned to fit that, remove the carbs & heads, Dawie was to fit Alfa 75 12V 3L heads & 6XJenvey ITB's, siimilar set up to my 147 with GoTech mngmt.
I've discussed the way forward with Dawie & now we are talking turbo. I stick with the big bore but replace the Ross high compression pistons for low compression versions, he suggested 9:1.
The big capacity ensures bigger power at lower boost, I'm looking at 0.5bar, running 95 pump gas & target is around 330-350hp at the wheels.
What's the opinion on here, should I go turbo or not?
Any advice? Is it worthwhile or better.
TX,
John

[JohnGTA]

I need some feedback. I have 2 GTV6 3L's, the red one is stock standard & that I'm keeping that way, my white one though presently runs a Glenwood Motors big bore 3.5l.
I'm happy with the performance but after just finishing my 156GTA with big bore & turbo, well it's changed my perspective a little.
I have a brand new Alfa 75 3L box with the 3.5:1 ratio & LSD & initially I planned to fit that, remove the carbs & heads, Dawie was to fit Alfa 75 12V 3L heads & 6XJenvey ITB's, siimilar set up to my 147 with GoTech mngmt.
I've discussed the way forward with Dawie & now we are talking turbo. I stick with the big bore but replace the Ross high compression pistons for low compression versions, he suggested 9:1.
The big capacity ensures bigger power at lower boost, I'm looking at 0.5bar, running 95 pump gas & target is around 330-350hp at the wheels.
What's the opinion on here, should I go turbo or not?
Any advice? Is it worthwhile or better.
TX,
John

Just to elaborate, much has been written & many times I beleive we have all at some point overplayed the power game but I have had modified versions of both the 24V & 12V V6 & from my experience ALL things being equal, my big bore 24V on ITB's,304degree cams, high compression bottom end(12:1) have made a best without the assistance of methanol but they CANNOT in this state of tune run on pumpgas, I've had to use AVGAS (101RON) minimum, have made 220wkW at Johannesburg altitude, that's 300whp at 7000rpm.Rev-limit is 8000rpm & power tapers off from 7600rpm, anyone says more & it's BS.
I live at the coast & when I have had the car trailered back home & tested them on a similar dyno, similar weather conditions at the coast the best I have seen is 326whp but I have to use 104 unleaded Sonoco for the thing to run equaly well at the coast.
On a 12V V6 with the same set up (ITB's) at the coast 285whp at 6300rpm.There is not that much in it.Dawie tells me that with forced induction one can get similar outputs out of either set up but cubic capacity can make a big difference.The advantage though is that from a turbo set up I could get say 300whp-350whp, not much more from either the 12V or 24v N/A set up's on ITB's & wild cams but it would be usable & run on regular pump gas.
SONOCO Race Fuel costs R45-65pl(104-119RON)& you have to buy it in cans which means you can't really take the car out on a decent drive, it becomes a pain to use.

Any comments?Cost wise forced induction also seems to make sense but what about the drivetrain on a GTV6?
How does it cope?

[kevin]

John, i had lunch with Victor and Frank who both have twin turbo GTV 12v running 280kw at 0.6 bar boost. These guys have had there TT gtv's since 1990. They are twin brothers as well but back to point they have special jigs made to pull 5th gear off as they forever stripping gears. Theynhave both been through 6 boxes but few crown and pinion failures. It seems that more crown and pinion failures occur with the track guys while these guys who do mainly drag racing break gears.
Domingoes and stewart on the other hand have their gearboxes upfront and not one failure in 15 years.
SO THE big question should be is where are you going to put your gearbox ? Unless you just drive the car smoothly and gently.
My 3.7 with my own plennum and 10.5 comp makes 192kw the same day yours made 220kw. But they did not take your car to full rpm . I think they stopped at 6000rpm.
Point is I have a batch of broken pinions from only 192kw. While with my standard 2.5 12v i ran 35 sessions of 10 laps and not one issue. So i deduce i can make a box last for my 2.5 at 95kw on wheels but not for my. 3.0 24v at 156 kw or my 3.7.
John bite the bullet and put box upfront or buy stewarts old car which is complete from Doms brother. It has 33mm torsions with alfa sei stubs and upside down ball joint from chev.
Its all there

[JohnGTA]

Kevin,
Thanks for the response & wise words. You have seen what my 3L GTV6 looks like & not because it's my car, I'm sure you will agree that it's one of the best still left.
I'm going to stay true to it's origins, N/A.
I'm not looking for more power but rather more usability & ease of tune but keeping it simple.
I'm going to reduce the CR from 11.2:1, which in a 12V is like running 12.5:1 in a 24V, down to a straight 10:1, still using forged Ross pistons off 100mm bore, same block.Then fit Alfa 75 heads with big valves & cams with a bit more advance to what I have at present & more duration as well, presently using 288's, so I will go with 304's, reduce the low down torque & make it a little more rev happy & run AHM ITB kit with GoTech engine management for fueling, still keeping the distributor for simplicity. Don't ask how but I've obtained 2Xbrand new complete dizzies for 3L
I will then set up for 95LRP & then for race fuel when required.Easier to tune than the carbs, more reliable & still in keeping with a choke per cylinder principle.
If I still make 160wkW on 95LRP here at the coast I'm happy. I'm going to fit the 75 3L box as the 3.5L can pull the longer ratio just fine, I will set the rev limit at fail safe, 6800rpm & try for peak power between 6300-6600rpm, it will last forever.I have several spare carb airboxes & I will use them as a basis to fabricate an airbox to fit the ITB's giving the motor that standard look when you open the bonnet.

As for my blue car, down at the coast on race fuel as it cannot run on pumpgas it made a best of 240wkW but it holds it flat all the way to the rev limiter at 8K.Different dyno though & it was in this blistering heat wave that we had over the whole summer here at the coast, high 30's to early 40 deg C. I will try now that it's cooled off.I've added meth & a further 6 injectors, they come in from 4500rpm, made 282wkW
For those alfisti in other parts of the world, a V8 M3 on the same dyno that Kevin & Dawie ran my GTA up in Johannesburg makes 198wkW, so we were 22wkW better, 1300rpm before it peaks, that tells the picture.
My 156GTA turbo also reduced a gearbox to pieces but that was at 1.2bar boost.
We now run at 0.48bar & the 3.7turbo made 440kW/620Nm on a hub dyno.Dawie gave me the numbers last night, so ask him which hub dyno it was on, I think that it was DOC's in Edenvale, where they tested Stuart's Ultima 2XTurbo Alfa?
That is monstrous, on 95unleaded pump gas as well.
I will come up to collect the car towards the end of May, when the Ultimate Street Car Challenge takes place at Zwarkops, I hope to see you then?
Did you decide to post pics of my 3L GTV6?
Ciao

[JohnGTA]

Kevin, Did you break the original 3L GTV6 trans or the 75 3L 3.5 with LSD type?
What about the straight cut CR gearboxes that Dawie has been making up of late?

You see, I don't want to change the basics of the car, so I would rather do what I would call, enhancements to the original, as I've done to suspension & so on.
3.5L 12V on 6X45mm Jenvey's.300bhp at the fly & around 320-350Nm on 95LRP is my target but I will still accept 280-290bhp, as long as I can fill her up at a normal filling station & not with cans at R45pl
She will not run at present with 98BP race gas or AVGAS at proper max timing, minimum is 104 SONOCO & she loves 119 SONOCO(R65pl
I mean BP race fuel at R17pl or AVGAS which I buy in bulk 200L drums at R15.80pl I can live with, considering pump gas is at R9.58pl here at the coast but R65pl & syphoning out of cans is a real pain in the a....se to put things mildly.
That for our fellow alfisti is e0.96pl for pump gas & e6.60pl for 119SONOCO consumed by the carbs at a rate of 5km/l.
It's not nice but I would still live with it if I could pull into a normal gas station & fill her up but now I just take her out for a short burst & never venture more than 50-100km out of town. I did that once, had to put in pump gas & then the next day remove the cylinder heads.......................right mess I made.

Kevin,
With the same investment in money I made close to 500kW at the motor with a 3.7L 24V 156GTA that it cost me to make 330kW(at the motor) in my N/A ITB 3.8L in my 147GTA.
The 156 runs smooth as silk on 93unleaded pump gas, pulls from idle in 6th all the way to max,my 147 is a b1tch, needs race fuel & you have to keep things on the boil well & beyond 5500rpm for things to happen.
For road use a plain Jane mild big bore is the way to go or you want more then turbo.The way things are happening now with the metro cops, maybe it's best we run the damn things totally stock?
Ciao

[kevin]

John thats a great option.Its worth a go to use that 3.5 ls with the straight cut box made by Henderson. Its got a tall 1 and 2 with a very close 3,4 and 1:1 5th. That is a very strong crown and pinion. Dougie is gonna test it in his 3.7 race car . I would like to see it used for a race before i get one as its pretty steep in price. Probably about 40 grand for box. For drag racing the straight cut box should be perfect with those loadings.

[MD]

For drag racing the straight cut box should be perfect with those loadings.

I am speechless,

To use one of the best handling chassis that Alfa released on the consumer market and use it for drag racing has got be a no-brainer

Kevin, get off those vitamin pills. They are not doing you any good.

[JohnGTA]

For drag racing the straight cut box should be perfect with those loadings.

I am speechless,

To use one of the best handling chassis that Alfa released on the consumer market and use it for drag racing has got be a no-brainer

Kevin, get off those vitamin pills. They are not doing you any good.

MD,
I couldn't agree with you more. That's why I refuse to change the transmission location.
I've had some good discussions with Dawie & Kevin, I've decided on what to do. I purchased a 2nd hand 75 3L QV engine, Dawie got it for me from a source in Europe, cost me e1800.00 complete & it's a runner.
I have instructed Glenwood to rebuild it to 3.5L spec with forged bottom end & a 10.5:1 CR, a good compromise for performance & to run on pumpgas, we will use a cam profile similar to the actual Group 1 race cars which ran 3L with 10:1CR, Dawie has a real wild profile at 304 inlet & 312 exhaust duration, far more radical than the present carb fed motors 288's.
This will reduce the low down torque but give more hp at the top end which is what I want, the 75 injection heads are also far better than the GTV6 carb heads so we go monster valves etc. I will feed this motor on 50mm Jenvey ITB's, will drink fuel like a pig but should be fun, I am going full Gotech & doing away with the dizzie & single coil.
I am also installing a brand new 75 3L gearbox with LSD & 3.5:1 final drive & my original GTV6 3L gearbox & motor I will store in crates, maybe one day I sell the car & then the original bits will all be there in mint condition.
I reckon this is what I would call a GTV6 3L EVO if there was such a thing just an enhancement of the original theme.
I will post photos of this project.

As for the drag racing guys, that's why I built the 156GTA 3.7 turbo, as a present for them but it's a waste of time but ALL the M3 & AMG C63 drivers think that it's the best racing out, go figure?????
Ciao

[JohnGTA]

John thats a great option.Its worth a go to use that 3.5 ls with the straight cut box made by Henderson. Its got a tall 1 and 2 with a very close 3,4 and 1:1 5th. That is a very strong crown and pinion. Dougie is gonna test it in his 3.7 race car . I would like to see it used for a race before i get one as its pretty steep in price. Probably about 40 grand for box. For drag racing the straight cut box should be perfect with those loadings.

Kevin,
Dawie quoted me R40K for this tranny, if it works well then maybe I should tell him to keep the new 75 3L box then?
I've fitted the Alex Jupe Monkey Shift kit, what a pleasure to use the gearbox, best R1500.00 I spent on the car.
Ciao

[kevin]

Md you have to see what goes drag racing here and its not what you see at the sydney 'festival ':D
Colotti mailed me back to say they cant make a box for the torque of the 3.7.
Now im speechless. Whtas in that 75 imsa - gonna mail Harmen today.

[JohnGTA]

Md you have to see what goes drag racing here and its not what you see at the sydney 'festival ':D
Colotti mailed me back to say they cant make a box for the torque of the 3.7.
Now im speechless. Whtas in that 75 imsa - gonna mail Harmen today.

Kevin,
As I told you on the phone, Colotti asked me for a dyno graph for my 3.5L 12V & mailed me back that they cannot make a gearbox to handle it's torque
Well I ran the thing as a Group 1 3L for 26 years & the stock box survived to 33000km without replacement, then aother 4000km as a 3.5L & it's fine, it's the ratios that are terrible, I mean 6000rpm for 125mph? Yes it will pull clean through to 7000rpm & then some in 5th but it's nerve racking, I reckon that 5000-5200rpm at 125mph & then a solid & safe 6500rpm in 5th for a true top of say 150mph with ease.
I'm fitting the 75 3L box, it can't be worse than the stock GTV6 tranny & should provide far better accelleration as the gearing is far more usable.
Ciao