JJayB

Andial is still doing special projects and parts. In fact they just finished Porschmeister 3.8 GT2 conversion. (almost finished). They continue to do service on all 3.8 that they built.

TB993tt

It seemed to me that because Ruf was never involved in racing the 993 GT2s he never got a handle on the technology developed to make those 3.8l 640+hp EVO racers and possibly decided his own ~520hp motors were plenty in the reasonably lightweight 993s he built hence AFAIK he has never done a twin plug 993tt.
LAT on here has the most up to date highly developed RUF 993tt engine in his CTR2 which dynoed at the 580hp mark on single plug.

The main benefit of the twin plug on our cars is the ability to allow more mid range boost and higher peak torque number, but to do that means the tuner must be able to manipulate the boost control effectively....

Having said the above, there is no doubt that certain engine builders in the US have and are building high boost high hp twin plug 3.8 engines using fixed boost which whilst a little "unruly" (and would doubtlessly grenade at le Mans using full boost) seem perfectly suited for most people's daily driver needs

To build 3.8 with EVO type heads ie twin plug and sealing rings you need a very experienced builder. I would go with Porsche PhD, Protomotive maybe Bob Holcombe. The guy from Turbokraft seems to have pointed Jussi in the right direction but I don't know how much input he had in building the engine ?

Jean

I don't think there is one answer to this question. It depends what you are going to do with your engine.

Will it be a track car mainly, do you want to go all out on the boost side, turbos, rods, etc.. The choices for the heads are also very critical, do you upgrade springs, valves, guides, or do you stick with stock for a milder performance engine.. Do you go with mechanical lifters or stay with hydraulic?

If you are looking for a high performance engine, almost everything has to be changed or upgraded, then the bill will be hefty, and the complexity just the same.

There are small tricks that need to be done if one wants to build a high performance 3.8 engine, each builder has his own, and I am sure each has a different POV. I was surprised to see how many things were not as simple as they seem while doing a top end rebuild recently, from the different ring sizes (thicknesses) and gaps to the valve guide lengths, etc.. there are many different options to use, all of them for a 3.8 engine. It is not that simple.

If you want to twin plug, then that is a new complexity, doing the holes is simple, but using two stock size spark plugs weakens the heads, the niro rings also, so you need to weld the heads, otherwise you can use EVO heads which had smaller plugs, to weld the heads you need special alloy matching the heat characteristics of the RR350 etc.. not very simple.

For a street driven moderate tune 3.8, things are much simpler.

Three years ago when I was planning to do my engine build, I had the engine crated to be shipped to Sportec then I changed my mind because they do not do twin plug, and they were sticking to 3.6ltrs, while it is not a must, I wanted those changes. RUF doesn't either...

Any 3.8 high performance engine will have its life reduced dramatically if used as it is meant to be used.

I agree with TB993TT on the above, he made a very good summary. The only thing I do not fully agree with though is that the GT2 TAG based racers all had fixed boost control, for several reasons, one of them is tuning facility, the other is practicality during racing, and another is the control it gives in different situations, that one does not get with an ECU controlled boost, nevertheless, fixed boost if properly used can be a very reliable option but you will be leaving some torque on the table for that.

tar6day

Jean,
What is the "ballpark figure" on the cost of your 3.6 to 3.8 conversion? Anything you would have done different?
Thanks,
Tim

vincentdds

Here 's my Protomotive built 3.8L Twin Plug being tuned on an engine dyno.

Bradford

Vincent, which intercooler are you using for your new monster?

tar6day

Vincent,
What kind of HP did you see?

vincentdds

Scott

Protomotive IC and hard pipes .

vincentdds

Spend the money and go with the guys that built these 3.8TT engine for a living. Also remember very few tuner in the US who can tune the Motronic on these engines right.

Jean

Tim, the build price is VERY dependent on how far you want to take it. A GT3RS oil pump alone will make a difference of $3k+, do you need it? Not really, but it is better to have one maybe if you track regularily.

It all depends on what you want to do with your engine. You don't need to put niro rings, you don't need a special intercooler, you don't need pressure sensing, you don't need equal length headers or mechanical rockers, etc if you just want it for a fun and still very powerful street car. You can get your 600+HP with that, for the duration of an acceleration run as we've seen from Jussi's run.

However, if you want to track seriously your car, all bets are off, and cost can be double.

I would say you can go from $20k to $50k. For $30k you get an excellent street engine.

As far as to what I would have done differently, definitely I would have gone the MAF route, being that I live so far away from my tuner, and it does impact somewhat drivability in traffic jams and needs more fine tuning. I would also go with BB turbos.

tar6day

Jean,
thanks. just thinking.

sealbeach1

WOW!!!

That being said I really appreciate the input that you have all offered. I know now that I must really think this through. I know I want go to the 3.8 ltr.

The twin plug is another issue all together. Here in So. CA we are limited to 91 octaine and in the hot rod world porting the heads is the answer to run higher compressions. My previous Cobra ran 10.5 to 1 compression on pumped gas because of the head work. I know it is different in the turbo world but does the twin plug offer help in performance using 91 octaine?

Thanks, You guys are amazing.

Kevin

Twin plugging offers you the safety factor that will save your engine when running crap 91.

With 91 and the 102mm liners I wouldn't build one without the twin plug setup. I would go as far as welding the fins and installing the EVO flame rings to lock the heads in place. Money well spent on a engine in hotter ambient temps.

Acropora

From the niro ring/head welding/twin plug/tune from protomotive to the turbos/carillos from Kevin I wouldn't change a thing in my engine build.
Well, maybe smaller compressors/intercooler upgrade/case locks as this car now is 75% track run.
With this build and suspension you can smoke race vipers on the track and leave them scratching their heads as to why.
I posted a while back questions re. the engine build and you can research the pros/cons folks offered. Twin plug is a must w/ 91 octane and it's gonna cost you. An alternative is to run 110 octane or more but just one mistake and your engine can detonate.

PorschePhD

Any race turbo motor Porsche built was twin plug. Hell, I do not go a half of point or above 1 bar without twing plugging on a air cooled motor.