997.1 GT3 to 4.0/4.1 litre?

[BrendonJ]

Dear all,

As above, does anyone have any recommendations of a company in the UK that has done this before? (preferably more than once).

I know FVD in Germany has been doing them for quite a few years but I have heard mixed reports.
It would be for a trackday car so would have to be pretty bulletproof/ the car/engine would be used in anger.

Any estimates of hp increase and rough cost would be appreciated.

Many thanks
BJ

[IMI A]

JZM, 9e , Parr, Autofarm, Fearnsport, ESM - all worth a chat and they all build their own engines with 12-24 month warranty etc from a few of them.

[isaldiri]

Manthey in Germany have a 4.1 conversion and one above that used to be 4.4 but I believe that one has been scaled back to 4.2 now. If I'm not wrong the 4.1 conversion was a 65hp gain and years ago I think the price was €40k (probably ex VAT)

[Cheib]

Read up on the Sharkwerks conversion, there are quite a few pieces covering it...there own car is a 997.2.

Vid here about it https://www.youtube.com/watch?v=k7DjqGUKiao

Obviously not going to get them to do it but worth reading as much as possible!

[MDL111]

Sharkwerks - I forgot who their UK agent is
Manthey as mentioned
RS Tuning (possibly marketed by Cargraphic - can't remember)
Doesn't Ruf have an n/a 8-cylinder engine (not relevant I know and likely retarded expensive)

No first hand experience on any of them

Edit: I think flemke on here once mentioned he had a Manthey built 4.4 or similar engine size. might be worthwhile sending him a message.

Regarding hp figures - I saw a 996.1 GT3 for sale with (I think) a Manthey built 3.9 and c 460hp according to the advert. I think it is for sale at Teichmann Racing in Germany (mobile.de)

Edited by MDL111 on Sunday 15th January 15:54

[Slippydiff]

MDL111 said:

Sharkwerks - I forgot who their UK agent is
Manthey as mentioned
RS Tuning (possibly marketed by Cargraphic - can't remember)
Doesn't Ruf have an n/a 8-cylinder engine (not relevant I know and likely retarded expensive)

No first hand experience on any of them

Sharkwerks UK distributor : Regal Autosport

Manthey : Hopelessly overpriced.

Cargraphic = RS Tuning : UK agent Parrs

Matt at Fearnsport built a Mahle based (Cup car/Gen 2 997 GT3 barrels and pistons) 3.8 with uprated cams, uprated induction system, uprated exhaust manifolds and system last year. It produced 475hp and 350 torques.

Not many others in the UK I'd trust to build a big horsepower N/A GT3 Mezger.

[wtdoom]

just abject horror at some of the recommendations given in some of the posts above

Edited by wtdoom on Sunday 15th January 23:28

[jimmyslr]

Could try Richard chamberlain at CTR. He's built some very handy Porsche engines.

[MDL111]

wtdoom said:

just abject horror at some of the recommendations given in some of the posts above

Edited by wtdoom on Sunday 15th January 23:28

do tell in case I ever am in a position to buy and then build my perfect GT3. Would be good to be able to come back to this thread as GT3 engine bible

[Yellow491]

You want it bullet proof and reliable,then leave it alone and get some driver education.
Why dont porsche make a 4.1 to 4.5!

[BrendonJ]

All,

Thankyou for the comments so far, much appreciated.

Some good companies to try there. I will give them a call.
Jzm are great and have set my previous GT3's up beautifully. But yep their engine rebuild prices are astronomical.
Fearnsport have a good reputation.
9e are building bigger turbo engines (and did my 996 turbo) so will have a chat to them as well.

Slippy, many thanks, it's always good to hear your experienced opinion.

Wtdoom, an interesting comment, it would be good to hear which ones you'd avoid. Could you expand please or email me on brendon jones at hotmail dot com

Many thanks

Edited by BrendonJ on Monday 16th January 09:23

Edited by BrendonJ on Monday 16th January 09:23

[BrendonJ]

Yellow491 said:

You want it bullet proof and reliable,then leave it alone and get some driver education.
Why dont porsche make a 4.1 to 4.5!

Cheers, but as I've been doing trackdays for 18 years, have previously raced Exiges and Formula Fords, and we've been hiring Mike Wilds for 6 years I think I'm covered there.
And just because Porsche didn't/couldn't do it 10-15 years ago when the engine was designed/with the tolerances they had to work with doesnt mean improvements cant be made in 2017

[IMI A]

BrendonJ said:

Yellow491 said:

You want it bullet proof and reliable,then leave it alone and get some driver education.
Why dont porsche make a 4.1 to 4.5!

Cheers, but as I've been doing trackdays for 18 years, have previously raced Exiges and Formula Fords, and we've been hiring Mike Wilds for 6 years I think I'm covered there.
And just because Porsche didn't/couldn't do it 10-15 years ago when the engine was designed/with the tolerances they had to work with doesnt mean improvements cant be made in 2017

Ah hello Brendon I think we have met. I'd ask Ken why none of the Indys thus far seem to be able to build a mezger to Porsche's own 4.0 500 bhp spec. That spec engine in an early GT3 will be magnificent if it can be done.

There are horror stories at every builder. Ninemeister who WTDOOM has built an amazing RSR with have had horror stories in the past. OPCs have rebuilt engines that have required sometimes a few rebuilds after an initial rebuild hasn't stopped oil leaks on 7.1 GT3 RS engines.

All engines are relatively expensive to rebuild. Forgot to mention Redtek and RPM worth a call too. Personally for reliability reasons I don't think I'd go beyond 3.8 unless someone can build to exactly the same spec as Porsche's own 4.0 mezger. Ruf also do a 4.2 500bhp Mezger but again it will be expensive.

[Slippydiff]

IMI A said:

Ah hello Brendon I think we have met. I'd ask Ken why none of the Indys thus far seem to be able to build a mezger to Porsche's own 4.0 500 bhp spec. That spec engine in an early GT3 will be magnificent if it can be done.

There are horror stories at every builder. Ninemeister who WTDOOM has built an amazing RSR with have had horror stories in the past. OPCs have rebuilt engines that have required sometimes a few rebuilds after an initial rebuild hasn't stopped oil leaks on 7.1 GT3 RS engines.

All engines are relatively expensive to rebuild. Forgot to mention Redtek and RPM worth a call too. Personally for reliability reasons I don't think I'd go beyond 3.8 unless someone can build to exactly the same spec as Porsche's own 4.0 mezger. Ruf also do a 4.2 500bhp Mezger but again it will be expensive.

Morning I, Nick at Redtek prefers to stick to building air-cooled motors these days.
But as you've said, once you start going off piste and do a custom Mezger build, it gets expensive and you are, to all intents and purposes "on your own" when it comes to sorting issues and dealing with problems regarding reliability. If you go with what are the perceived big names such as Manthey and Ruf, you should be in safe hands (albeit you'll be paying exhorbitant prices), however this isn't always the case, I've heard horror stories with both Ruf and Manthey conversions.

I know of several custom 3.8, 3.9 and 4.0 996/997 GT3 conversions, all have proven to be hugely expensive and very frustrating to bring to a successful conclusion, though once they've been sorted, the results are something to behold in the early watercooled chassis.

I'd planned to have a 3.9 Sharkwerks motor built for my Gen 1 997 GT3 (they were just about to bring their 4.1 conversion to the market, so it's likely I'd have actually gone with the larger capacity) I was in talks with Regal Autosport and it was suggested Alex would fly to the UK to build and oversee the mapping of what would've been the first SW UK big bore 997 conversion.

However, having driven the car (it was only ever going to be for road use) I figured the increased performance (along with fitment of Ohlins dampers) really was "gilding the lily", so I abandoned the project and returned to the 996 fold.

Brendon, do please PM me if you wish to discuss any of the above further.

[hondansx]

The reality is as soon as you start fiddling, things go wrong.

Remember getting power out of the (dreaded!) Rover K-Series was tough work and went through every single respected specialist engine builder. And it's the same for any engine, not just the infamous K-Series; my Mustang's 'bullet proof' V8 went 3x last season and its £30k a pop to have an engine which can win at a Historic Masters race.

I've switched from one man bands, to well known companies who build engines for Le Mans teams and they've all had problems. Ultimately it only takes one mistake and you have a grenade waiting to go off - particularly disheartening when you send a 'perfect' engine for a refresh/rebuild and it expires on the next outing.

Oh, and of course, like lawyers, engine guys get paid whatever the outcomes!

I guess what i'm saying is you can't have it both ways; you either stick to OEM or accept you are going to have a money pit forever more - depends how much you love the car!

I think Porsche put something like 50,000 miles (mentioned in a Christophorus magazine) in their GT4 race car program. I would be more than happy to try the likes of Sharkwerks, who say they only release after thorough testing, but we both know that isn't 50,000 miles pounding round a track. The reality this is an expensive job and there are so few around that EVERYONE is the guinea pig.

I'm hoping to do it though; plan to get a couple of the Sharkwerks kits and see if i can permission to use my own engine builder.

[Steve Rance]

Notoriously difficult to do this without problems. It took porsche a long time to come up with the 3.8 because of problems that they encountered increasing from 3.6. I'd stick the porsche motorsport 3.8 pistons and barrels in from the Cup engine and be done with that. Its an easy upgrade thats proven. Not sure what - if any - head work would need doing but having raced against cars with that upgrade, I can tell you that it is very effective. In real terms it is not exprensive. I'm not sure that i'd be comfortable going 4.0 no matter who did it. I believe that the RSR engine ws 4.0 but it was an extremely expensive unit to run when compared to the 3.6 and 3.8 cup units. If you are starting from a 3.8, i'd leave well alone. Metz engines dont go wrong often but when they do it's usually VERY expensive to fix them

[Digga]

<cough>GT2!</cough>

[nxi20]

Steve Rance said:

Notoriously difficult to do this without problems. It took porsche a long time to come up with the 3.8 because of problems that they encountered increasing from 3.6. I'd stick the porsche motorsport 3.8 pistons and barrels in from the Cup engine and be done with that. Its an easy upgrade thats proven. Not sure what - if any - head work would need doing but having raced against cars with that upgrade, I can tell you that it is very effective. In real terms it is not exprensive. I'm not sure that i'd be comfortable going 4.0 no matter who did it. I believe that the RSR engine ws 4.0 but it was an extremely expensive unit to run when compared to the 3.6 and 3.8 cup units. If you are starting from a 3.8, i'd leave well alone. Metz engines dont go wrong often but when they do it's usually VERY expensive to fix them

The Cup 3.8 pistons & liners are the way to go for reliability; I did a Capricorn 3.9 conversion but it suffered a piston/ring failure after 42K miles. The heads need a bit of port work to get the best from them (it used to be cost-effective to simply buy 997 Cup heads until Porsche whacked the price up) but it's the rods that are the real (potential) problem. The gudgeon pin is 23mm on the 3.8 vs. 22mm on the 3.6. Depending how much work the original rods have done, you can either open up the originals & install a larger bush or you simply buy a set of 3.8 rods. If you go for a full set of OEM Pankel titanium rods, don't expect much change from £7.5K Having experienced both the 3.9 & 3.8 extensively, my view is that the 3.8 is the sweet spot. The 3.9 doesn't give any appreciable increase in either torque or BHP but feels rougher than the 3.8

Because I like to live dangerously, my long-term plan is to build a 4.0 engine using the RSR crank which allows you to use the 3.8 pistons & liners with 4mm longer rods as per the 4.0 RS engine. This engine might be ready by 2018

Sticking to the original 76mm stroke, it's madness to go to 4.0 or larger IMHO. There's all sorts of problems with using such enormous bores, not least the fact that the water jackets were never designed to accommodate liners that large so they need to be machined to open them out & even then you have to use steel liners not the ally favoured by Porsche. The expansion coefficients of the different materials means there's a lot of piston slap when the engine is cold & it's this that I believe lead to the piston failure I suffered.

As others have said, you are very much 'on your own' when you start heading off-piste with the Mezger. It can be wonderfully rewarding but if it goes wrong, it's going to be frustrating & expensive. Think very carefully & do lots of research before jumping in.

Edited by nxi20 on Monday 16th January 12:27

[Slippydiff]

nxi20 said:

The Cup 3.8 pistons & liners are the way to go for reliability; I did a Capricorn 3.9 conversion but it suffered a piston/ring failure after 42K miles. The heads need a bit of port work to get the best from them (it used to be cost-effective to simply buy 997 Cup heads until Porsche whacked the price up) but it's the rods that are the real (potential) problem. The gudgeon pin is 23mm on the 3.8 vs. 22mm on the 3.6. Depending how much work the original rods have done, you can either open up the originals & install a larger bush or you simply buy a set of 3.8 rods. If you go for a full set of OEM Pankel titanium rods, don't expect much change from £7.5K Having experienced both the 3.9 & 3.8 extensively, my view is that the 3.8 is the sweet spot. The 3.9 doesn't give any appreciable increase in either torque or BHP but feels rougher than the 3.8

Because I like to live dangerously, my long-term plan is to build a 4.0 engine using the RSR crank which allows you to use the 3.8 pistons & liners with 4mm longer rods as per the 4.0 RS engine. This engine might be ready by 2018

Sticking to the original 76mm stroke, it's madness to go to 4.0 or larger IMHO. There's all sorts of problems with using such enormous bores, not least the fact that the water jackets were never designed to accommodate liners that large so they need to be machined to open them out & even then you have to use steel liners not the ally favoured by Porsche. The expansion coefficients of the different materials means there's a lot of piston slap when the engine is cold & it's this that I believe lead to the piston failure I suffered.

As others have said, you are very much 'on your own' when you start heading off-piste with the Mezger. It can be wonderfully rewarding but if it goes wrong, it's going to be frustrating & expensive. Think very carefully & do lots of research before jumping in.

Hi Nick. Having driven Ade's and now Cunno's car, I think it would possibly be more accurate to say your 3.9 was rougher, but my conversations with Matty indicated he was never particularly smitten, nor indeed convinced that your early Capricorn 3.9 piston and liner build was a "nice" conversion either mechanically or from an engineering standpoint.

Ade's 3.9 is silky smooth and mechanically silent (as are all Matty's builds in my experience), but my guess is, his engine is using a later iteration of the Capricorn pistons and liners which have differing piston to bore clearances, and thus don't have the same clearance issues when cold, but also have improved ring packs to reduce oil consumption. That's supposition on my part, but I'm sure Neil would be able clarify the finer details.
Unfortunately, it would seem you and others were the expensive guinea pigs for the Capricorn piston/liner development program.....
As we've both said, if you go off piste with the Mezger, the learning curve is frequently steep and expensive, but once sorted, it makes for a very rewarding package.

[Steve Rance]

The Motorsport 3.8 barrel and piston set is pretty much plug and play on the 3.6 cup engine. Most owners these days opt for the 3.8 set when rebuilding as there is hardly any cost difference than a standard 3.6 rebuild. I'm not too clued up with the specifics of the road engine but i doubt that the bottom end would differ much?

The Met is definately not an engine that i would modify. It's been developed as a motorsport unit over a long time and the gains V risks for modification are too marginal for me anyway. One of the reasons I went with a 997.1 GT3 was that I wanted the 3.6 unit. If you do go ahead, good luck. The 3.8 conversion does give strong performance. I could out qualify Mike Donovan (just) in his 3.8 but couldnt keep up with it over a race distance. The grunt out of the corners was very impressive.