9A1 engine into 996 Carrera (Jethro B)
Discussion
Just reading through the current issue of evo and my mouth dropped on reaching Jethro Bovingdon's fast fleet update. His long-broken red 996 has just had an engine swap, Litchfield have replaced his broken M96 with a 3.8 9A1 from a 2014 Carrera S. Refabricated engine mounts, adapter for 996 gearbox, 996 Cup electric PAS pump, exhaust, wiring... Apparently it's all up and running well.
I actually thought this was a late April fool at first, but on reflection Jethro's TG USA earnings plus Litchfield's enthusiasm and the publicity opportunity all combine to make it possible. Sadly it sounds like the work involved mean it's unlikely to ever become a standard conversion.
https://twitter.com/BenJacksonTP/status/1380843512...
I actually thought this was a late April fool at first, but on reflection Jethro's TG USA earnings plus Litchfield's enthusiasm and the publicity opportunity all combine to make it possible. Sadly it sounds like the work involved mean it's unlikely to ever become a standard conversion.
https://twitter.com/BenJacksonTP/status/1380843512...
CocoUK said:
Blimey!
He’s been on quite the journey with this build, I’m not sure what to think of sticking a 991 3.8 in the back.
It probably wouldn’t be mine or many others first choice but then look back at early Pork, not too unusual to see engine swaps?
that was my thought as well, quite a few 70s Porsches running 993 or 964 engines, so it is kind of in keeping with the history of hot rodding 911s He’s been on quite the journey with this build, I’m not sure what to think of sticking a 991 3.8 in the back.
It probably wouldn’t be mine or many others first choice but then look back at early Pork, not too unusual to see engine swaps?
I can't see how a bells and whistles Hartech capacity increase build wouldn't have been cheaper, easier and netted similar results. Or surely a crashed GT3 engine could have been sourced and fitted for what's been spent on all the fabrication and shoe horning.
While the 9A1 fixes a lot of the m96/7 issues it also loses what someone described "the gravel" of that engine.
While the 9A1 fixes a lot of the m96/7 issues it also loses what someone described "the gravel" of that engine.
are confirmed.ooid said:
didn't that car already had a rebuilt engine when he got it?! Seriously, 996 has just became literally the most expensive Porsche out there!
Yes. But I believe it had done well over 200k miles before it's first rebuild. It belonged to poppopbangbang (on this forum) who replaced it with another 996 which I believe is over 300k now.You can still pick one up for about 12k wait for it to break or do a future proof rebuild on the engine for c£10k. 997.1 has similar engine issues and a 997.2 will stand you for at least £30k. But don't think that puts you clear of risk as there have been a few reported borescore rebuilds on early ones of those.
nunpuncher said:
I can't see how a bells and whistles Hartech capacity increase build wouldn't have been cheaper, easier and netted similar results. Or surely a crashed GT3 engine could have been sourced and fitted for what's been spent on all the fabrication and shoe horning.
While the 9A1 fixes a lot of the m96/7 issues it also loses what someone described "the gravel" of that engine.
Engine mountings are different for the GT3 engine so that hits the similar snags as fitting the 9A1 engine. The 9A1 has only 5 shafts to spin (crank and cams x4) as opposed to the Metzger six that has 7. Slightly lower CoG as well. While the 9A1 fixes a lot of the m96/7 issues it also loses what someone described "the gravel" of that engine.
I’m getting the impression that Jethro is doing this because he can and afford it.
On the smoking tyre podcast he suggested they did it because in theory it didn't seem that difficult. He suggested Lichfield thought it might be a conversion they could offer customers. However, it's apparently been a total pain in the hole and I think all plans of doing it again are in the bin. He said the main issue has been trying to get all the electronics talking to each other.
I greatly admire anyone who takes the plunge with a project like this. It's a bit of an unknown whether you'll ultimately be satisfied with the end result but you'll certainly have something quite unique, which in itself is cause for celebration.
People often scoff at the monetary side of a project like this whilst ignoring the experiential value!
People often scoff at the monetary side of a project like this whilst ignoring the experiential value!
I think it is great to see such an unusual build, I don't really see a huge benefit though compared to a 3.7 hartech build? I imagine it will be slightly more powerful but the additional (assumed) cost will wipe that away in my eyes.
Either way, i hope he does a video/ write up once it is finished.
Either way, i hope he does a video/ write up once it is finished.
I believe the timeline was along the lines of;
A long time ago...
- Engine borked and initially diagnosed as terminal by RPM
- Options mulled over and landed on a new 3.4l X51 block from Porsche Classic
- Engine strip down and fault identified as rebuild not required by Porsche Swindon
- Everything put back together and used sporadically while work took him over seas with Motortrend and TG-USA
- Then as per linked evo update, things took an interesting twist while over at Litchfields!
I personally thought a new, super rare, 3.4 X51 Porsche Classic block was a mega solution, although it may have been an impossible dream with little/no available parts.
I haven’t read the evo article but pleased JuanPablo has built his 911 hot rod, the overall spec sounds immense, must be a corking drive.
It’s a shame Litchfield can’t make the engine swap economical, having thought about it, I’d be tempted...
A long time ago...
- Engine borked and initially diagnosed as terminal by RPM
- Options mulled over and landed on a new 3.4l X51 block from Porsche Classic
- Engine strip down and fault identified as rebuild not required by Porsche Swindon
- Everything put back together and used sporadically while work took him over seas with Motortrend and TG-USA
- Then as per linked evo update, things took an interesting twist while over at Litchfields!
I personally thought a new, super rare, 3.4 X51 Porsche Classic block was a mega solution, although it may have been an impossible dream with little/no available parts.
I haven’t read the evo article but pleased JuanPablo has built his 911 hot rod, the overall spec sounds immense, must be a corking drive.
It’s a shame Litchfield can’t make the engine swap economical, having thought about it, I’d be tempted...
Edited by CocoUK on Wednesday 14th April 21:40
I'd hazard a guess at it being the ancillary parts availability that kiboshed the X51 plan, speaking as someone who tried to order a large number o them a few years ago.
The actual block for a 3.4 litre X51 is almost identical to a stock unit, same crank, rods - but different pistons.
It's the heads where things get interesting, with the ports reworked and the cams changed (hence the pistons requiring more clearance for the valves). Porsche did re-start production of the aluminium intake manifold for the X51 engine, but that alone isn't going to get you (or Jethro) the higher rev performance that he was after, and (I suspect, I've not read the Evo article) played a part in why he went for the Cayman engine.
What he was after (I believe) was an engine that performed like the X51, which was designed by Porsche at a time when they were considering using said engine in the Cup cars - a decision that went in favour of the Mezger in the end of course.
The actual block for a 3.4 litre X51 is almost identical to a stock unit, same crank, rods - but different pistons.
It's the heads where things get interesting, with the ports reworked and the cams changed (hence the pistons requiring more clearance for the valves). Porsche did re-start production of the aluminium intake manifold for the X51 engine, but that alone isn't going to get you (or Jethro) the higher rev performance that he was after, and (I suspect, I've not read the Evo article) played a part in why he went for the Cayman engine.
What he was after (I believe) was an engine that performed like the X51, which was designed by Porsche at a time when they were considering using said engine in the Cup cars - a decision that went in favour of the Mezger in the end of course.
I’m putting 2+2 together here, but for what it’s worth, I believe this may have been the 991 CS scrapper Litchfield pulled the engine from - based on vintage, description, damage and location.
Gawd knows how I stumbled across it but thought I’d share for any fellow car-geeks that have followed the rebuild journey!
Gawd knows how I stumbled across it but thought I’d share for any fellow car-geeks that have followed the rebuild journey!
Hmmm
Cool idea, but I can imagine the electronics would have been pretty tricky on the basis of my experience (the Cup engine was “relatively simple” in comparison) no FBW throttle, no Variocam, runs Alpha N etc. The trickiest bit was adapting the Motronic ECU to drive the resonance flaps in the correct sequence.
Jethro’s car will be a cracking thing to drive, and that 9A1 will have plenty of torque care of its increased capacity, added to which there’s still a fair chunk of additional horsepower on the table (should he decide 400 isn’t enough)
Of course, it won’t scream (or thrill) like 997 Cup engined Mk 1 punching out over 460 gee gees
http://911uk.com/viewtopic.php?t=135064
Cool idea, but I can imagine the electronics would have been pretty tricky on the basis of my experience (the Cup engine was “relatively simple” in comparison) no FBW throttle, no Variocam, runs Alpha N etc. The trickiest bit was adapting the Motronic ECU to drive the resonance flaps in the correct sequence.
Jethro’s car will be a cracking thing to drive, and that 9A1 will have plenty of torque care of its increased capacity, added to which there’s still a fair chunk of additional horsepower on the table (should he decide 400 isn’t enough)
Of course, it won’t scream (or thrill) like 997 Cup engined Mk 1 punching out over 460 gee gees
http://911uk.com/viewtopic.php?t=135064
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