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Pros & Cons opinions per G50 in old 930

Pros & Cons opinions per G50 in old 930. I believe I want to put a G50 in my old 1979 930. Anyone out there have any input? 930 has 2K on fresh engine -Carrillo, 964 cams, Leask, B&B, MSD, Single plug, K27, Turbo Kraft IC, etc. Probably close to 400HP. Car performs very well with the exception of lack of gearing. Seems like G50 with 5 speeds would be more desirable than re-gearing 930 4 speed. Any input/suggestions appreciated.

EP Slick

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Old 07-03-2009, 06:48 PM
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Doug Siegel
 
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Hey Slick,

I've been studying gear ratios day and night. The cost of the Patrick Motorsports G50 set-up, not including labor is over 11k. And, might make the wheels spin too much. (Which is why perhaps the g50-50 is a taller set of ratios.)

Currently I've got a super tall 1st gear, taller 2nd, stock 3rd, and a shorter 4th. The car doesn't want to move off the line, but once it gets going, every shift is leaves me in the power band. But, my set up is only good for the track IMO. Not what I want.

I'm hoping that there is away to optimized the 4 speed. I'm not home right now so I can't give you the gear charts and ratios, but basically, my solution:

Stock 1st or lower to a 15:36 (I think) Which basically mimics the g50/50 1st.
Lower 2nd 2 steps, which is one step higher than a g50/50 2nd gear.
Lower 3rd gear 1 step (Which still allows you to cruise in the low to mid 3k rpm at 65 mph)
Lower 4th (I'll report later)

The tranny Cleve is selling is a stock 1st, and a 2nd, 3rd, and 4th that mimics the g50/50.
By using the 1st 4 gears of a g50/50, the highway cruise at 65 and 80-85 doesn't sit well in the rpm range IMO, thus is good primarily for the track.

Having tall gears with the power to support them is great. But, for me, getting the thing off the line is difficult. My first gear takes me to 60 mph at 6000rpm. So, the gear is usable and quite fun once I get to 2500 rpm. But lots of around town b.s. driving requires a quick response short first gear and a 2nd gear that doesn't lug.

If you keep a four speed, my suggestion prior presents a question.

A shorter 1st gear desires an exponentially shorter 2nd gear, so 2nd allows us to feel the turbo thrush immediately. 2nd gear is where most of the fun should be IMO. So, the shorter the better. BUT, 3rd gear needs to be tall enough to cruise at 65 mph in the low 3k rpm range. So, 2nd gear can't be made so short that it screws up 3rd gear. Hence, lower 3rd by one step, lower second by 2 steps. (lower fourth...I'll give info tomorrow),,,,,and 1st gear becomes a question.

Leave it stock and enjoy the benefit of blasting off in 2nd gear, or lower it and possibly have some lag whence shifting to second.

Opinions???

At 6000rpm
g50- 38mph
g50-50 42.5 mph
930- 48 mph
doug's car 60.

How many of you guys with stock gears wish for a shorter 1st? I can't remember what my stock 1st felt like. I don't want to rebuild mine a 3rd time.

Hope this helps you Slick.
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88' blk/blk 930: Haltech EFI, Twin Plug, Pauter Rods, Nascar Bearings, custom crank work, dowel pinned case, ported manifold and heads, Kokeln I/C, SC Cams, Turbonetics ball bearing 62-1, BB headers, RARLYL8 Zork, additional 993 oil filter, plx/inyourface gage, RS style coilover, Fikse FM10-17 wheels, TIAL 46mm 1 bar. (where the heck did all my money go?)

Last edited by dsiegel360; 07-03-2009 at 10:53 PM..
Old 07-03-2009, 10:51 PM
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I had a G50 w/LSD from Patrick Motorsports in my old 87 930 (just sold last month) about 10 years ago. To me, it one of the best upgrades performed during my ownership, it cost me about $8K parts and labor. I live in the San Francisco area and it made the car more drivable for the roads and speeds. Other upgrades I had were 964 CAMS, Euro fuel system, K27/7200 turbo, B&B exhaust. The car could spin it's wheels in first gear on demand...

Steve
Old 07-03-2009, 11:11 PM
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I have a 4 spd that at 60 MPH I'm at about 2750 + or - a RPM in 4 gear,I shortened 1st and 4th,left 3 and 4 stock and run a 8.41 R/P. other mods are 964 cams.. euo fuel head... headers from powerhaus... monster I/C from powerhaus... Fuel enrichment system... custom built 3LDZ ( runs more efficient the the K 27).. if you want the gear set, I can sent you the numbers and what it graphs out to be... It makes it very desirable drive around town ( stop light to stop light) on the free at 65PMH I'm at 3 K rpm. GARY
Old 07-04-2009, 01:21 AM
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Doug Siegel
 
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Quote:
Originally Posted by berg0658 View Post
I have a 4 spd that at 60 MPH I'm at about 2750 + or - a RPM in 4 gear,I shortened 1st and 4th,left 3 and 4 stock and run a 8.41 R/P. other mods are 964 cams.. euo fuel head... headers from powerhaus... monster I/C from powerhaus... Fuel enrichment system... custom built 3LDZ ( runs more efficient the the K 27).. if you want the gear set, I can sent you the numbers and what it graphs out to be... It makes it very desirable drive around town ( stop light to stop light) on the free at 65PMH I'm at 3 K rpm. GARY
Gary,
I'd be interested in your gear ratios. Sounds like a great box...as long as you stay away from long highway driving. I'm assuming that at 80-85 mph, you are at 3800-4000 rpm.
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88' blk/blk 930: Haltech EFI, Twin Plug, Pauter Rods, Nascar Bearings, custom crank work, dowel pinned case, ported manifold and heads, Kokeln I/C, SC Cams, Turbonetics ball bearing 62-1, BB headers, RARLYL8 Zork, additional 993 oil filter, plx/inyourface gage, RS style coilover, Fikse FM10-17 wheels, TIAL 46mm 1 bar. (where the heck did all my money go?)
Old 07-04-2009, 06:30 AM
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What are you priorities? Stop light drag's, track, cruse...

Gears can make a big difference. However, there will always be compromises.

I think before spend I would spend $7-11k on a transmission I would do an EFI conversion to better match the motor to the transmission. I have seen this done and it worked very well.

If the issue is off the line starts in town, displacement, compression, turbo choice and EFI can make up for gears to a large degree.

Nice wide stock gears w a turbo that has a fat power curve can be very fast.

Having said that, many have reported that just drooping a lower R&P in has made for a reasonable cost improvement that significantly improved the car.

I like staying with the original design intent of the 930 so I would not mess with a conversion. I would stay w the 4 speed and look at a re-gear if needed for a special need like building a mostly track car.

For a street car I might look at close ration gears through 3rd that keep the motor in its power band. Then with 4th I would go with a gear that works on the freeway and keeps me at the ege of boost.

If a track car, I would look at close ratios that support a 4th no taller than is usable on most the tracks that will be run.

Most of us are so into making a big number in the HP instead of building there car to be the fastest it can be and put on turbos with to large a compressor and a small restrictive hot side. Even with my 91 G50/50 I was much happier and I think in many cases faster when I dumped my K29 and early 7006 based HF and went back to a K27-7200 with a few other tricks that woke up the early part of the power band.
Old 07-04-2009, 08:37 AM
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whne I did my coversion back in 1989. th eonly tranny out there was a Ruf 5 speed at 9 grand. I got my shortened 1st gear,my shorted 4 gear and my R/P ( 8.41) all gremany made for 1200 dollars. My friend had this gear set made ( 3 of them in 1983. So he had one left and sold it to me at his cost. So her are the gears
1st gear is 17/34-- that is shortened= 67,7 KM/h at 6000 shift point
2nd gear is 23/30-- that is stock--------- 104 km/h at 6000 shift point
3rd gear is 28/25---- that is stock--------- 152km/h at 6000 shift point
4th gear is 32/22---- that is shortened---197 km/h at 6000 shift point
the ring/pinion is a 8.41
that was all done using 215/60Vr tires
so for those that can power up to 7000rpm without running lean is makes for an all around strong stree car. this was done so that a stock 930 ( no mods ) would never see lag time. so you can imagine what much more scary it would be if you had mods done.
I run 285 40's on 15 inch. at 35 I've had the tires break loose, on stock tires when shifting 1st thru 3rd, you break loose. GARY.
Old 07-04-2009, 09:25 AM
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for us people on in calif. how do you my smog inspection on an EFI system. gary
Old 07-04-2009, 09:30 AM
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I like the 930 4 speed the way it is. I just want to raise the compression ratio to 8:1 so there is more very welcome low speed torque.

Then open the intake ports and intake manifold openings to 40mm from the stock 32mm while port matching them to some 40mm aluminum injector blocks I have to help the top end horsepower.
Already have the usual bolt ons and 964 cams for around 350-380 flywheel horsepower with stock 7:1 compression and 1 bar boost.

3000rpm in fourth gear is about 80mph. I like getting around 21mpg cruising on the highway.

Last edited by JFairman; 07-04-2009 at 07:52 PM.. Reason: 4th gear correction
Old 07-04-2009, 10:58 AM
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well this set-up make it very drivable and you have alot of bottom end torqe and you rev very quickly,so quick that you will hit 7000rpm very quickly. My mod. turbo starts at 2200rpm,I'm at full boost by3000rpm (1.1bar) so living in the bayarea there isn't many places you can get to 160 mph. 4th gear pulls like 1st gear. you just top out at 145 @6700rpm. but you get there very quickly. with my set-up I made 385 RWH at 5100RPM and 394 RWH@4950rpm no head work was done. my turbo ran out of power at 5100 ( that what the guy dyno'ing said). I have since upgraded the turbo by putting a bigger wheel in the same size housing. I haven't been to the dyno since my last upgrade. But I could feel the pull where the last turbo fell off. One more thing I've run a K27 back in 89 so I quess that would be the 7006. I've run with th e11 hot house and the 13 hot housing. Then I sent both my K27 and my 3LDZ (which is a schwitzer turbo) a guy where He said that by mod. the 3LDZ he made the efficentcy improve by 50% over the K27. What that means is you now how you car runs when its 40 or 50degs out side. imagine you running like that at 70 degs.thas how the turbo responds the incoming temp is cooler then when running the K27. by the way I also monitor in/out temp from the inter cooler. GB
Old 07-04-2009, 12:19 PM
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Oh yes I did give up my gas mileage,but then again I drive a gas saver to and from work and save my toy for joy rides. GB
Old 07-04-2009, 12:22 PM
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Doug Siegel
 
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Slick,
Rarly runs a 915 tranny. Perhaps an easier and cheaper conversion (I don't know).....but limited HP capability.

Great Thread!

Like JFairman, I would love higher compression even at the expense of less boost. But even so, stock gearing is for the autobahn. A 3.2 N/A has very short gears. Raising compression and lowering boost still IMO begs shorter gears....but not as short as the g50/50. I'm running 500-600hp. Rarly is in the 300's and loves his 915 short gears. AND, he'd probably kick my ass in a race.

I think I've settled on
15:38
18:25
28:26
31:22
stock 9:38 r/p

google "transmission calculator" and test'er out.
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88' blk/blk 930: Haltech EFI, Twin Plug, Pauter Rods, Nascar Bearings, custom crank work, dowel pinned case, ported manifold and heads, Kokeln I/C, SC Cams, Turbonetics ball bearing 62-1, BB headers, RARLYL8 Zork, additional 993 oil filter, plx/inyourface gage, RS style coilover, Fikse FM10-17 wheels, TIAL 46mm 1 bar. (where the heck did all my money go?)
Old 07-04-2009, 07:33 PM
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FWIW I have a G50/03 that is ratiod and heavily reinforced --zero use since rebuilt.
I had this Trans in 930 ( and subsequenly in a 993) and is big plus in the early car compared to 4 speed. It is for sale( here on Pelican) .
Couple of points--- the G50/03 is considerably lighter than a G50/52.Perhaps most importantly in relation to this thread it is also a lot shorter in length than a G50/52.
Old 07-04-2009, 08:06 PM
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FWIW I have a G50/03 that is ratiod and heavily reinforced --zero use since rebuilt.
I had this Trans in 930 ( and subsequenly in a 993) and is big plus in the early car compared to 4 speed. It is for sale( here on Pelican) .
Couple of points--- the G50/03 is considerably lighter than a G50/52.Perhaps most importantly in relation to this thread it is also a lot shorter in length than a G50/52.
Old 07-04-2009, 08:06 PM
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Ya, a G50/50 tranny in my car would be very cool, but not at that cost. On the way to making my car more drivable, I changed the ring and pinion to a shorter set, bumped the compression and went EFI. Now, around town, the car is perfect - great low end, great throttle response, and so on. A G50/50 would be perfect on a technical track like Barber, but Road Atlanta the 4sp is just fine now. $11k is a lot of money for a tranny when there are so many other improvements that can be made for that kind of money.
Old 07-04-2009, 08:50 PM
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Crotchety Old Bastard
 
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My $0.02
Unfortunately a 915 won't work for you at your power level.
The track gearing you have sux on the street so at least first gear needs to be lower. You have done those calculations.
Also your torque curve needs to be as broad as possible. You already have EFI so that is no additional help. Dump the big turbo for something with more mid-range and then tune the cams and ignition for low end torque.
The combination of all of these things should make you more happy for the least amount of money.
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Old 07-04-2009, 09:13 PM
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Doug Siegel
 
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Quote:
Originally Posted by RarlyL8 View Post
My $0.02
Unfortunately a 915 won't work for you at your power level.
The track gearing you have sux on the street so at least first gear needs to be lower. You have done those calculations.
Also your torque curve needs to be as broad as possible. You already have EFI so that is no additional help. Dump the big turbo for something with more mid-range and then tune the cams and ignition for low end torque.
The combination of all of these things should make you more happy for the least amount of money.
Rarly,
I don't want to fully hijack EPSlick's thread. The 915 was mentioned for his sake. 400 hp CIS.

As for my car, I've installed the hot housing that is actually appropriate for turbo I have, as suggested by turbonetics. I'll test her out when I get the zork and see where boost kicks in.

My sc cams are timed to web cam's guidelines. I don't know which end of the spetrum they are set. Any suggestions?

As for timing, I'd love to hear your thoughts. More advance or less on the low end?
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88' blk/blk 930: Haltech EFI, Twin Plug, Pauter Rods, Nascar Bearings, custom crank work, dowel pinned case, ported manifold and heads, Kokeln I/C, SC Cams, Turbonetics ball bearing 62-1, BB headers, RARLYL8 Zork, additional 993 oil filter, plx/inyourface gage, RS style coilover, Fikse FM10-17 wheels, TIAL 46mm 1 bar. (where the heck did all my money go?)
Old 07-04-2009, 09:51 PM
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Patrick isn't the only place to get a G50. I think if you were resourceful you might do it for 1/2 that. My total conversion was $4400 but I did all the work and that was a few years ago. And I didn't rebuild the tranny.

I have a ROW G50 in my car and the ratios are very close to the stock 915 that came out of my car. Which is fine for me cause it is a street car. The US G50 is a little taller geared I think, so that might be better with a turbo car.

The only con is cost.
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Old 07-05-2009, 03:57 AM
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Wo ist die Rennstrecke?
 
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Quote:
Originally Posted by dean View Post
Patrick isn't the only place to get a G50. I think if you were resourceful you might do it for 1/2 that. My total conversion was $4400 but I did all the work and that was a few years ago. And I didn't rebuild the tranny.

I have a ROW G50 in my car and the ratios are very close to the stock 915 that came out of my car. Which is fine for me cause it is a street car. The US G50 is a little taller geared I think, so that might be better with a turbo car.

The only con is cost.
Where did you find the tranny? I couldn't/can't find one under $5k and that's without the pedal cluster, etc.
Old 07-05-2009, 05:45 PM
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Crotchety Old Bastard
 
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Boy I'm having troubles with this site or my computer. I posted a reply at lunchtime and it is not here. At the risk of ridicule I'll post my one data point concerning the 915.
Yes the 915 can live in front of a 400CHP 930 engine IF you shore up the weak spots and are mindful of them while driving.
I've had my 915/930 combo for about 10 years now with the only issue being one I caused at the drag strip. Don't do that.
The weak spots are the R&P bearing retainer, side cover, and 2nd gear.
I use the WEVO bearing retainer, stock late model side plate, and don't speed shift 2nd gear. With a mild 315 WHP (362CHP) I can lay down 0-100mph in less than 10 seconds. The gearing is really fun for auto-x and sharp curvy roads like the Dragon. There is no doubt in my mind that my car would push any 4spd 930 through the Dragon. Torque is always there nomatter the gear. Top end is 150mph @ ~6700rpm; it pulls hard all the way as you never drop out of boost.
I have another tranny built and ready to go in the car that has all the goodies, custom 5th gear, WEVO stuff, and factory oil cooler. I figure I can blow up a half dozen dozen or so 915s for the price of one G50 conversion so that is the plan.
Should you decide to do this "downgrade" you should keep your 4spd to protect the resale value of your car. It will also come in handy if/when you decide that 400CHP is no longer enough.

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Old 07-05-2009, 06:36 PM
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