930 G50/WEVO shifter conversion--initial review

[Bruce M.]

I've recently made the switch to a G50 from a 930 box, in a 1978 930, and I thought I'd share my initial impressions. I added WEVO's new G50 shifter as well. I won't bother you all with my build sheet, but I'm not sure how transferable my experience will be for most, since my car has a 500+ wheel hp (at 1 bar) built 930 engine with efi (Motec), and a 935 clutch.

But, given that, the switch was superb--right up there with the engine build and efi as the single best improvement in driveability on the car. The shorter first gear makes take-offs easy as pie in comparision--the 935 clutch is a pure puck design, so the modulation in the stroke is minimal. With a stock first gear in the 930 box, and the 935 clutch, I had to rev the crap out of the engine to get going, with about 1/2" of clutch travel to work with. Not any more; just "bump and go". First is no longer really a cruising gear past about 15 mph or so, but so far that hasn't proved to be a problem. Pedal effort is lower, and the clutch is therefore easier to modulate. The release point is quite high in the stroke, but, again, that is something I'm learning to deal with fine.

One caveat--I haven't taken this car back out to the track yet after the conversion. From what I can tell on the street I'll stay in the boost easier on the one hand, but I'll have to be doing a lot more rowing to avoid hitting the limiter, on the other. I also think I'll risk breaking the tires loose under boost quite a bit. We'll see next season.

I don't know what a G50 shifts like without the WEVO shifter, but the WEVO unit is excellent. Throw is nicely shorter (not NSX short, but also not school bus long, like a stock 930, and a bit shorter than my 930 box with a short shift kit was). It's taking me a while to learn the new shift planes, especially at speed, but the WEVO is quite precise and repeatable, so that shouldn't take too long. One cool side effect of using the shifter is it resulted in my very own "console delete", and with a black anodized shifter, and black leather interior, the cockpit looks very clean and purposeful. I spent some extra dough to get a nice boot made for the shifter, and to get new matched carpet for the area once occupied by the console, so it looks pretty tight.

The downside? Very very spendy. I bought a blueprinted G50 unit from Patrick Motorsports. It came with a new Guard torque-sensing diff, which is nice. I paid $6700, which included a $1000 trade-in I got on my old box, which had a good ZF style diff. The Wevo shifter was $600. The install was far too much money. My advice if you are not doing it yourself is to get someone who has done it before, and can comfortably and accurately estimate the time it will take. My wrench was a Porsche-only guy, but he had never done this conversion, and it showed in the time it took. Jim Patrick will tell you it's a 15-20 hour job, from the time you drive the car in until you drive it out. Not even close, in this case.

Right now, though, the car is pretty much where I've wanted it to be. The Motec and the G50/WEVO give it a certain quality of civility, but with lots of power and still good lightness. It's got good elements of both the old and the new in Porsche. It's been a long road. But now I get to drive it it in my custom-made machine...

[herman maire]

Pleeeeease post some pics of this car.

A G50 is also in the cards for my 72 RSR turbo but is waaayyyy down the road, for now I am stuck with the 915.

How quick is the 1 to 2 shift is it pretty instant? and how quickly can you shift this G50?

If you can Pm or post all the mods for the motor im sure others will be interested.

Does the MOTEC have knock sensors and what compression are you running.
500hp, is this with the k27 and what is the lag like ? I am thinking of a Bi-turbo 3.0L but I am stumped as to what turbo I will be going with.

would really apreciate youre feed back on this. I have so many turbo questions.

[ewave]

Is that a Carrera G50, or a real Turbo G50/50? (What are your gear ratios?)

[Bruce M.]

O.k., here's the build sheet.

I wouldn't characterize the shifting as "instant", but it is a heckuva lot better (much more precise, shorter, and quicker) than a stock 930. Dunno about a 915.

I'm sure the Motec could be configured for knock sensors, since it is a flexible unit, but I haven't heard of a reliable knock sensor for our engines yet, so I don't have one.

1978 930 3.3
Anthracite Metallic
Engine: 993 crank, 98 mm 7.5/1 Mahle Sport pistons (displacement now 3.45 liters); Carrillo rods and bolts, titanium retainers, competition valve springs; twin-plugged head, Niresist rings, Raceware head studs; Carrera manifold, AirResearch TS04 turbo; Siemens 72 lb/hr injectors; factory GT2 EVO cams; stainless steel, hand-fabbed exhaust (headers and muffler) with built-in twin HKS wastgates, 1100 cubic inch intercooler; Motec 48 Pro engine management, programmed on engine dyno, cockpit boost control with 5 settings--.8, .9, 1.0, 1.1 and 1.2 bar. Dyno figures: 512 hp at the wheels at 1.0 bar. Other: Big Reds up front, G50 hydraulic 5-speed conversion with Guard limited slip diff, WEVO G50 shifter, 935 clutch, Fikse FM-10s, 8s in front and 11s in back (running 315/35ZR17 Michelin Pilot Sports); front strut bar, 23mm torsion bar up front, 30mm in back with 200 lb progressive helper springs, custom valved Bilsteins all around, Charley bars front and rear; Ruf front spoiler with fogs, factory boxed rockers, Champion momo wheel, gauges reconditioned by North Hollywood, 935 boost gauge in place of clock. All engine work, and exhaust, performed by Bob Holcombe of Motorsport Design in Scottsdale. Additional Motec tuning by Chris' German Auto in Seattle.
Sunroof coupe, black leather interior; special ordered from the factory in 1978 by Ted Williams and his son

[Bruce M.]

It's a Carrera G50. I wanted the shorter first, given my clutch, and there's a lot of good experience around that says you can feed the G50's a lot of power and they'll hold up fine...

[herman maire]

thanks
this is getting off topic but Is there much lag with Motec and TS04 ?
what rpm does the boost kick and where does it fade off? or can it pull cleanly to 7k rpm ?
also what is the throttle response like when youre in the boost range is it similar to a NA motor where the response is electric.
I have never driven a heavy boosted car just mild boost this is why I ask this lame questions.
Oh and if you get a chance post some pics
thanks

[Bruce M.]

I don't have any recent pics to post, unfortunately. I should take some here pretty soon, though, come to think of it.

The Motec sharpens throttle response, off and on boost, but it's not like a positive displacement blower or anything--that's part of the turbo experience. Boost comes on noticeably by about 3000 rpm and does not fade to redline.

I think my next performance upgrade will be maybe one of those HighFlow close tolerance turbos...