Hwyranger

David,
Contact Chris Carrol of Turbokraft. He gave me a very detailed estimate on a 3.8L twin plug conversion. Carillo rods, JE pistons, Nikki's cylinders, lots and lots of machining, garrett turbos, motec stand alone, and the rest of the fixings. I asked for a clone of the "Marc" motor he built several years ago. It's on his website. I'm also in So. Cal and Tempe, AZ is not far at all. Estimate ran in the low to mid $50k range for everything. There are lots of variables, depending on whatcha want....
Enrique

vincentdds

If you're in the AZ area I would also recommend Bob Holcombe. He had built many high HP 3.8 engines and is considered the best of the best.

Jean

Both of the above builders have a good reputation it seems, however they both work with Motec, not Bosch Motronic. While it is not a matter of better or worse, it is just important to note that, and understand the pros and cons before making the choice. Also , for $50k (or much less) I would certainly be looking at Mahle P&C at a minimum!

Hwyranger

Jean,
Chris of Turbokraft seems to believe the JE piston/LN engineering "Nikki" cylinder is superior to Mahle. Do you disagree? if so, why?

PorschePhD

Not that anyone asked me but I have years of experience using Mahles and JEs. When tuning I have found that a Mahle has a better squish area than a JE and typically will take more timing than a JE. I have seen this through the years and continue to see it. JE says they will design whatever we ask, I have just stuck with Mahles. Doesn't mean that JEs are bad, just a difference.

Jean

Hwyranger

I don't know personally Chris Carroll but I heard good things about him, Jussi has used him and seems happy as well, however Jussi does not have enough miles or abuse on his car yet. I have run my Mahle for close to 3 years now in VERY extreme weather and heavy track usage, they are still perfect.

Mahle is what the reknown Porsche engine builders "that I know" use, both in Europe and the US, my engine builder has been doing many 3.8 TT conversions for many years and he would not use anything other than Mahle after having tested other less expensive ones.

Here is a thread that had some lightweight discussion around the topic, there are many others as well if you search.

https://rennlist.com/forums/showthre...ns#post2619183

You can get a full 3.8TT conversion for $30-$35k on Bosch Motronic using Mahle P&C.

P.S. just saw PorschePhd's post, one more experienced opinion.

Hwyranger

Jean,
If you don't mind me asking, could you pm me the specs of your build. I've contacted Andial, Mode, inc., and Turbokraft, all three were $50k plus. Mode being the most expensive. Who do you recommend? Thanks again, you are a wealth of porsche knowledge.

Jean

Hwyranger

I did not mean to say that my engine build cost me $35k, but rather that you can get one done comfortably for close to that price. There are board sponsors who are very qualified to do it, PorschePhd is a very experienced builder for instance.

My build is basically the same as many others, twin plug, twin Garrett, headers, exhaust, LWF assembly, twin fuel race pump, MAHLE, Carillos, special head sealing, head work (springs, valves, retainers, guides etc..), Pressure sensing (no MAF) , Bosch Motronic with boost controller, Intercooler, injectors, etc..

pstoppani

FYI - Kevin at UMW is doing a twin-plug 3.8 conversion for me right now. Certainly another excellent source for info and for having the work done.

Hwyranger

Should the crankcase be left at the stock 107mm or should it be machined to allow the thicker 109mm cylinder? I understand once you go 109mm, you're stuck and there's no going back. However is it safer/or a more sound build to uprate to a 109mm?

Kevin

Go with the 109mm. The cylinder liner is very thin with the 107mm drop ins. Why would you go back?? I suggest welding your 1st fins up on your cylinder heads also, along with adding flame rings.

LA964RS

Kevin...what's the update on your 3.8 monster?