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Recently I've finished 24v conversion in my AR75 and honestly I'm not impressed with it's performance. I need to do some extra work arround diagnosis of electrical components and will switch to new type intake + 45mm OD inlet pipes + shorter gears. After that I'll take her to dyno.

For now it runs with (long) 3.545 gearbox and modified old 6c plenum. From 0-100km/h in hot sunny day, she goes arround 7.7 sec which is equivalent to something like ~185 HP..

What results did you guy's achieved after conversion? What is the rate of transmission power loss for our boxes?


Thanks for any input, it would be good guide for resolving & finding eventual problems.
Brg, Lazar

fit a TS gearbox and watch the figures drop...

24v feels less torquey on low revs, 12v is mighty strong compared to 24v. above 4000 rpm the 24v comes on song.

One converted 75 24v over here used to have a 1.6 gearbox behind it but that was a bit short on the highway...

Mr Belgrade,

If you want to change your 75 from a slug to a go kart, put a 4.1 diff in it. The 3.59 is for chasing gazelles in South Africa.
The latter diff was for the American market chasing economy during the fuel crisis? The former is for performance.

Thank you, comments can really inspire!
I have one 4.3 ( from AR 75 1.8 ) and started working on it.

dobrý deň

The 4.1 is a good compromise between accelleration and fuel economy. The 4.3 would be more suitable for a 2 litre engine or less. You may find it a bit too short for a V6.

sbohem

Giving a recommendation without more info is pure guessing.
First it depends on how high you rev it. Equally important what's the use.

For twisty tracks a 4.56 would be good. If it revs high even 4.78.
Normal tracks or compromise of track/road a 4.1 would be OK.
More comfort or road driving maybe a 3.91. This would also be good on faster tracks if you rev high.
For fuel economy, comfort, top speed or fast tracks with power and not revving high the 3.55 would be good.
And optimum fuel economy with the longest I knwo which is 3.35

Dobar dan MD!

Thank you for guidelines; my AR75 is a bit of everything; track day, meeting car, maybe drift too...

Fuel economy and top speed are irelevant as long as tehre is a good feel of acceleration. I did some comparison between std gears from 164S - 75 1.8 and it came up a bit shorter on 1.8 side.

I want a car that it's a bit brutal; don't want a car for which I'll say; ok it goes & sounds nice, so I think that 4.3 is exactly what I need - not to mention that it came up almost for free.

Did some diagnostic of electrical components; lambda probe is dead (again) & two COPs havent passed the exam, have to replace plugs and test them again. Furtunately AFM is working like new.

hey neighbour

put that short gearbox and smoke some rubber, thats the purpose of the car.

my 3 litre bitch woke up today and i have a 4.55 diff. cant wait to make a test drive in da hood.

I'd be inclined to tackle things a bit differently but what I'm going to sujest would cost more but should help get better all round peroformance from the car.

After reading more than once about the effects of overly large inlet ports and their negative effect on torque production just about every where in the rev range, I'd be very much inclined (funds permitting) to take the heads off, put them on a flow bench and see how much modelling clay could be added to the port floor befor it starts to drop actual flow figures http://mototuneusa.com/the_2007_superbike.htm.

Another approach is http://www.gofastnews.com/board/technic ... ncept.html.

Combining the 2 methods above (even David Vizard says that the ports in his example head were to big) should/would help to gain some big improvements.

Adjustable cam sprockets to help dial in the broadest torque curve (even with factory cams).

I would also look at making a long runner inlet manifold similar to the 1 used on the Nissan 300ZX.

Then see if your engine needs to hide behind a low diff ratio for decent performance .

On our Conversion, we are getting around 270 hp at the crank and have a 4.1 Milano Plantium transaxle. It is so much better than the original set up. Not as fast as the M5 or F355, but as good as the 328gts and much more stealth.

I thought that a stock 164LS 3.0L 24V had 220 hp at the crank. Maybe you just need to retune it? For sure the transaxle makes our GTV6 quicker but the engine is no dog. It really screams when it is running properly.

Duk, I would rather go for supercharging than playing with heads... For n/a engine price/power = large numbers.

CChan,

Do you have any friends with a 328 GTS? I think your car would beat a 328 GTS. You must realize, that Italians are a creative bunch, especially when it comes to quoting BHP figures.

Hi Zamani,

The 328 GTS was the next italian sport car that I bought to supplement the GTV6. I purchased it new in 1988 and I really liked it. It is definately slower than my GTV6 is now but looks alot better. I traded the 328 GTS for the F355 and the F355 was definately the best sports car I had till then.

I think there must be something wrong with installation. Even with a 3.55, the 24V should be pretty damn fast in a 75

anyways, Squadra racing chip seems to make a good, very noticeable increase in mid-range power, and some up high too. But make sure all is well before doing "performance" upgrades.