Steve's 3.0 24v supercharged GTV

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Joemart
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Re: Steve's 3.0 24v supercharged GTV

Post by Joemart »

wow... nice post :twisted:

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Re: Steve's 3.0 24v supercharged GTV

Post by kevin »

Hi Steve , exhaust looks good . Did you flatten the section to get the oval looking pipe or did you buy it like that . I have seen squashed pipe here at Autosport but it costs a fortune . You mentioned coil overs on the konis - any pics of that . I will drop a pm as I need to get a spigot with brass made for my new flywheel so looking for good machine shop guys .
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Kevin

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Steve R
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Re: Steve's 3.0 24v supercharged GTV

Post by Steve R »

Cheers Kevin, I had the exhaust shop make the flattened part, I think they just carefully squashed some 3.5" pipe for the that section! I'll PM about the engineering shops I've used locally.
83' GTV6, 3.0 24v supercharged

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Steve R
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Re: Steve's 3.0 24v supercharged GTV

Post by Steve R »

Figuring it would need more stopping power for the more powerful motor, I followed much the same upgrade route well documented elsewhere on this site.

I did the rears a few years ago using SZ vented rear disks with steel spacers inserted into the standard GTV6 calipers, you can spot the disks in the earlier exhaust photo's.

The fronts are Alfa 147 GTA 305mm disks, with 4 pot Brembo radial mount calipers from a Porsche and are the lighter weight mono block versions.

The GTA disk center bore was machined to fit the GTV6 hub and a bracket made to locate the caliper in the right place, I put the pad edge as close to the edge of the disk as possible for maximum leverage. These fit under 16"'s no problem, but don't fit under stock 15" rims. I've a new 164 master cylinder to improve pedal feel, but haven't gotten round to fitted it yet as it already feels OK, I'll do this

The only significant variation on my brake version compared the other options people have used is the retaining method for the disks and wheel studs. Rather than have custom alloy bells made to hold the studs behind the disk I simply re-purposed the old disks :-

Open up the center of the new disk on a lathe to fit snugly on the hub center.
Cut all of the old disk off in a lathe, just leaving the center ring that holds the studs.
This already perfectly aligns for the hub and simply fits behind the new disk.
The studs then protrude through the 5x98 holes, therefore the studs are now the thickness of the new disk center shorter than before = 5mm. I forget the exact number but there are still something like 11 or 12 full turns of thread on the wheels nuts.
Two small countersunk screws locate it together - as per standard disks.
The wheel nuts provide the clamping force for the wheel to disk to hub - as per standard.


Attached a couple of photo's taken during build and mock up with old parts to illustrate this home made brake kit better than just words, you can see the super inexpensive mounting bell option made from the old disk!
Attachments
brake kit.jpg
brake kit.jpg (126 KiB) Viewed 5194 times
brake kit mock up.jpg
brake kit mock up.jpg (108.36 KiB) Viewed 5194 times
cut down disk = brake stud adaptor.jpg
cut down disk = brake stud adaptor.jpg (93.04 KiB) Viewed 5194 times
83' GTV6, 3.0 24v supercharged

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Steve R
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Re: Steve's 3.0 24v supercharged GTV

Post by Steve R »

About time I updated this thread. I had become unhappy with the "one belt does all" set up, despite building it like that deliberately. With hindsight it was a mistake, so I've re-vamped the set up to use a secondary belt solely for the supercharger, with the other accessories on their own belt in the same way factory blown cars are set up.

Basically the belt was so long that it was difficult to get the correct tension permanently! One event that helped make my mind up involved the tensioner (a stock ford part) flexing enough to allow the belt to walk forwards and shred itself. Fortunately the car was idling at the time, equally fortunately I was at Alex Jupe's garage so he didn't mind my fixing it outside!

This time I've also engineered it with removable pulleys so I can alter the boost levels. My smallest pulley was sourced from a power steering pump on a Honda Accord, a larger one was cut off a ford crank pulley. These give 6 and 9.5 psi boost respectively and I'm currently running the low version for the time being then will put the higher version on for dyno fine tuning.

Some photo's to follow:

as you can see the additional pulley is bolted to the front of the existing crank pulley, drilled and tapped to accept 6x 12.9 grade socket headed bolts spaced evenly around. I figure this does not alter the engine balance in any way as the new addition is neutral.
Attachments
from the front
from the front
pulley front.jpg (89.73 KiB) Viewed 4795 times
test fitting the pulley
test fitting the pulley
pulley top.jpg (103.42 KiB) Viewed 4795 times
83' GTV6, 3.0 24v supercharged

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Steve R
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Re: Steve's 3.0 24v supercharged GTV

Post by Steve R »

I removed the supercharger and bracketry, cut off the mounting lugs and re-welded them 28mm further back such that the nose of the supercharger is that distance further forward to align with the new bottom pulley set up.

This also involved extending the throttle body mounting flange so that it didn't foul the inner wing strengthening member.

At the same time adding another tensioner just for the SC belt. I wasn't happy that previously bought items were weak, so I made my own out of 90 degree section steel. This is welded to the bracket:
Attachments
revised bracket.jpg
revised bracket.jpg (217.02 KiB) Viewed 4795 times
tensioner.jpg
tensioner.jpg (176.38 KiB) Viewed 4795 times
tensioner 2.jpg
tensioner 2.jpg (123.83 KiB) Viewed 4795 times
83' GTV6, 3.0 24v supercharged

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Steve R
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Re: Steve's 3.0 24v supercharged GTV

Post by Steve R »

New throttle flange being made and tack welded to the mounting bracket before final welding, finishing and paint :
Attachments
flange 2.jpg
flange 2.jpg (144.63 KiB) Viewed 4795 times
flange 1.jpg
flange 1.jpg (198.77 KiB) Viewed 4795 times
83' GTV6, 3.0 24v supercharged

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Steve R
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Re: Steve's 3.0 24v supercharged GTV

Post by Steve R »

Whilst everything was dismantled I took the opportunity to fix the main coolant radiator that was weeping slightly from a seam. To be fair it was the original 1983 radiator that had been rebuilt twice before, so I'd gotten good use from it.

Rather than have it fixed again it's replaced with fully welded all aluminium race rad design for a Golf VR6 as it's very close in dimensions, better made and cheaper. Cut off and re-welded the mounting lugs of my 156 GTA fans to fit and at the same time changing the fan switch to the twin temperature facet version talked about elsewhere in the forum (thanks Jim K), altering the wiring with a separate relay circuit for each fan. The first fan now comes on around 84C, and generally that's all that's needed, the second fan triggers around 87C if necessary. The car now runs nice and cool with a very stable low to mid 80's.

Made some "feet" to mimic the GTV6 factory mounting lugs and a top mount to use the top center factory mount. You can also see the alloy blanking sheet at the bottom to ensure the rad fully seals into the aperture of the engine bay, all of the air goes through the rad, none can bypass top, bottom or sides.
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rad & fans.jpg
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83' GTV6, 3.0 24v supercharged

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Steve R
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Re: Steve's 3.0 24v supercharged GTV

Post by Steve R »

Another unusual problem encountered involved the air-filter trying to collapse in on itself when the throttle was wide open! The air demands of the engine exceeded the old filters' max flow, so a larger dual cone K&N item with 90mm (3.5") alloy pipework has been installed, as before the filter is outside the engine bay behind the headlights, this is the largest filter that will fit in the space.

New and old for comparison, the new one is rated for more than 400hp, the smaller one is unrestricted up to about 250. As you can see I managed to bend it back into shape, it's still a great item and I'll re use it on another car.
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filters.jpg
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83' GTV6, 3.0 24v supercharged

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Steve R
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Re: Steve's 3.0 24v supercharged GTV

Post by Steve R »

Had a couple of silly teething problems to resolve with the new set up, most awkward to find was an irritating high pitched whistle at closed throttle at all speeds. This turned out just to be a poor seal between the supercharger inlet and the mounting bracket allowing a sliver of air to be sucked in and whistle an annoying tune! Once the cause was spotted it was easily fixed with a new sealing gasket.

Very happy with it now, the new red and chrome colour scheme is just for aesthetics.

Goes like stink :-)
Attachments
NS view.jpg
NS view.jpg (220.47 KiB) Viewed 4794 times
OS view.jpg
OS view.jpg (221.96 KiB) Viewed 4794 times
83' GTV6, 3.0 24v supercharged

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Re: Steve's 3.0 24v supercharged GTV

Post by KevinR »

Very nice Steve , like the pulley set up on crank . Busy with another 24v conversion and was looking for another pulley set up . Look forward to seen you at a few events this year . Let me know which ones you're going to .
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Kevin

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Steve R
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Re: Steve's 3.0 24v supercharged GTV

Post by Steve R »

Hi Kev,
I don't have anything much planned Alfa wise this year as I've quite a lot going on with family weddings, holidays and such.

If Alex holds another open day I'll be there though :-) Any suggestions welcome.
83' GTV6, 3.0 24v supercharged

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Steve R
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Re: Steve's 3.0 24v supercharged GTV

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83' GTV6, 3.0 24v supercharged

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Steve R
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Re: Steve's 3.0 24v supercharged GTV

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83' GTV6, 3.0 24v supercharged

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75evo
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Re: Steve's 3.0 24v supercharged GTV

Post by 75evo »

Nice sounding car mate. If I go to Cornwall next year, I'd like to pay you and Kev a visit!

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