PARR 3.9 GT3 Conversion
Discussion
Interesting article in GT Porsche magazine this month. Features a 997.1 GT3 with a 3.9 ltr engine conversion to give 450BHP and 314LbFt torque.
Article states....
New piston and liner set that increases the stroke by 4mm to 104mm. The bore is unchanged from the standard 3.6 at 76.4mm. Compression ratio rises rom 12 to 13:1. The article states that the standard titanium conrods have been retained but lighter ones can be specified. This conversion is completely reversable to take the engine back to a 3.6 if you want to.
Price is listed at £12500 odd (plus the VAT) which is almost half the price of the Sharkwerks 3.9 conversion .... I think the Sharkwers conversion involves a re-bore of the block and gives around 500BHP but dont know for sure
Article states....
New piston and liner set that increases the stroke by 4mm to 104mm. The bore is unchanged from the standard 3.6 at 76.4mm. Compression ratio rises rom 12 to 13:1. The article states that the standard titanium conrods have been retained but lighter ones can be specified. This conversion is completely reversable to take the engine back to a 3.6 if you want to.
Price is listed at £12500 odd (plus the VAT) which is almost half the price of the Sharkwerks 3.9 conversion .... I think the Sharkwers conversion involves a re-bore of the block and gives around 500BHP but dont know for sure
I raced against a couple of 997 cup cars with that conversion in GT cup driven by Donovan and Hogarth. Along the Rivett straight they pulled out 100m on me. At the time, the championship was run on power to weight. After practice I went to see my engineer and said 'Mike and Paul are running a lot more power than us'. 'I know' he said 'we built the engines'. I didn't bother protesting - it was a non championship series at that time and I wasnt that bothered. Carerra cup was more important to us.
Could out quailyfy them but in a race situation, their power realy told as my tyres went off.
Devistaingly effective upgrade for the race track - Cant see the point on a road car though
Could out quailyfy them but in a race situation, their power realy told as my tyres went off.
Devistaingly effective upgrade for the race track - Cant see the point on a road car though
V8KSN said:
Interesting article in GT Porsche magazine this month. Features a 997.1 GT3 with a 3.9 ltr engine conversion to give 450BHP and 314LbFt torque.
Article states....
New piston and liner set that increases the stroke by 4mm to 104mm. The bore is unchanged from the standard 3.6 at 76.4mm. Compression ratio rises rom 12 to 13:1. The article states that the standard titanium conrods have been retained but lighter ones can be specified. This conversion is completely reversable to take the engine back to a 3.6 if you want to.
Price is listed at £12500 odd (plus the VAT) which is almost half the price of the Sharkwerks 3.9 conversion .... I think the Sharkwers conversion involves a re-bore of the block and gives around 500BHP but dont know for sure
It'll be the stroke that remains unchanged at 76.4, but the kit consists of new pistons & liners which take the bore to 104mm (13:1 compression would indicate it's probably a Capricorn piston & liner kit). One of the strengths of the Mezger design is the ease with which the pistons & liners can be changed: no "rebore" required.Article states....
New piston and liner set that increases the stroke by 4mm to 104mm. The bore is unchanged from the standard 3.6 at 76.4mm. Compression ratio rises rom 12 to 13:1. The article states that the standard titanium conrods have been retained but lighter ones can be specified. This conversion is completely reversable to take the engine back to a 3.6 if you want to.
Price is listed at £12500 odd (plus the VAT) which is almost half the price of the Sharkwerks 3.9 conversion .... I think the Sharkwers conversion involves a re-bore of the block and gives around 500BHP but dont know for sure
To get near to what SW claim to get on power, you need to change the cams & exhaust at the very least; Parr are getting about what you'd expect power & torque wise without making major changes to injectors, ECU replacement (not just a remap) & exhaust.
BTW, I suspect "lighter conrods" just means the latest revision of 997 Cup rods which save a massive 3 grams off the 997.1 rods - at a cost of £800 per rod.
ArcticGT3 said:
I'd suspect the difference is probably a little smaller if both run in the same dyno. Horses seem to be a little smaller stateside ;-)
The other possibility is that Americans are known to often not be averse to running rather fruity high octane race fuel in significantly tuned cars. A little checking (and MON to RON conversion) indicates that they can get unleaded brews equivalent in our measures to about 109 octane. That may or may not factor into claimed dyno numbers... ?keep it lit said:
Cracker, good to see Mike having a go !DiscoColin said:
The other possibility is that Americans are known to often not be averse to running rather fruity high octane race fuel in significantly tuned cars. A little checking (and MON to RON conversion) indicates that they can get unleaded brews equivalent in our measures to about 109 octane. That may or may not factor into claimed dyno numbers... ?
On a F/I engine it can make a huge difference (if the ECU is mapped to take advantage of it) but on a N/A engine it wouldn't make much difference even with a new tune (save for maybe absolute extreme conditions - like a track day in 40C heat) where it would fight off The ignition being retarded.nxi20 said:
It'll be the stroke that remains unchanged at 76.4, but the kit consists of new pistons & liners which take the bore to 104mm (13:1 compression would indicate it's probably a Capricorn piston & liner kit). One of the strengths of the Mezger design is the ease with which the pistons & liners can be changed: no "rebore" required.
To get near to what SW claim to get on power, you need to change the cams & exhaust at the very least; Parr are getting about what you'd expect power & torque wise without making major changes to injectors, ECU replacement (not just a remap) & exhaust.
BTW, I suspect "lighter conrods" just means the latest revision of 997 Cup rods which save a massive 3 grams off the 997.1 rods - at a cost of £800 per rod.
Thanks for that explanation Nick To get near to what SW claim to get on power, you need to change the cams & exhaust at the very least; Parr are getting about what you'd expect power & torque wise without making major changes to injectors, ECU replacement (not just a remap) & exhaust.
BTW, I suspect "lighter conrods" just means the latest revision of 997 Cup rods which save a massive 3 grams off the 997.1 rods - at a cost of £800 per rod.
I must admit, I like the idea of 500BHP in my car but to be perfectly honest, I dont think it needs any more power! Certainally not for the road anyway and thats where mine spends 99% of its time.
It mine was tracked as much as yours I think I would go for it! Have you ever been tempted with a 3.9 conversion?
nxi20 said:
It'll be the stroke that remains unchanged at 76.4, but the kit consists of new pistons & liners which take the bore to 104mm (13:1 compression would indicate it's probably a Capricorn piston & liner kit). One of the strengths of the Mezger design is the ease with which the pistons & liners can be changed: no "rebore" required.
To get near to what SW claim to get on power, you need to change the cams & exhaust at the very least; Parr are getting about what you'd expect power & torque wise without making major changes to injectors, ECU replacement (not just a remap) & exhaust.
BTW, I suspect "lighter conrods" just means the latest revision of 997 Cup rods which save a massive 3 grams off the 997.1 rods - at a cost of £800 per rod.
Thanks for that explanation Nick To get near to what SW claim to get on power, you need to change the cams & exhaust at the very least; Parr are getting about what you'd expect power & torque wise without making major changes to injectors, ECU replacement (not just a remap) & exhaust.
BTW, I suspect "lighter conrods" just means the latest revision of 997 Cup rods which save a massive 3 grams off the 997.1 rods - at a cost of £800 per rod.
I must admit, I like the idea of 500BHP in my car but to be perfectly honest, I dont think it needs any more power! Certainally not for the road anyway and thats where mine spends 99% of its time.
It mine was tracked as much as yours I think I would go for it! Have you ever been tempted with a 3.9 conversion?
V8KSN said:
It mine was tracked as much as yours I think I would go for it! Have you ever been tempted with a 3.9 conversion?
I did it nearly 2 years ago mate. It's done 36K miles since then & is going strong. Keeps up with 3.8 GT3s / RSs on acceleration even though they've got the lower gearing. Gen2 gearbox is the next upgrade I think...I did try the Cup CWP conversion for a year before rebuilding the engine but tbh I couldn't live with it on the road. I'd say on track it just about evens out the performance between a 997.1 with the Cup CWP and my car with "stock" gearing.
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