hacker-pschorr

No, but some of the owners get really annoying.

Especially that a-hole Randy, what's his deal?






EDIT - I forgot about that David Hawkins, what a *****.

cold_beer839

I wonder what is the most STREETABLE pump-gas RWHP you could get from a GTS 5.4L after regrinding the cams, porting & polishing the heads/intake, larger valves w/ lite weight lifters, optimizing injector size and FP, and Sharktuning? With full length headers and x-pipe with 2.5" dual exhaust or y-pipe with 3.5" single exhaust. AND using the stock crank (i.e. no stroker crank). Base your opinion on a car equipped with a 5-spd gearbox.

Calling Greg Brown, come in Greg Brown.....

AO

You stickin' wit your suspect '93 rods?

Rob Edwards

Aw hell, there's nothing wrong with '93 R1 rods:

RyanPerrella

GREAT QUESTION!

This is what ive been pondering as well as its the direction i plan on going. But i would be replacing the rods and modifying the pistons as well.

With the SF bay area guys getting near 400 RWHP out of the 5.0 with stock valves and the exhaust you mention here but without the bigger valves (5.0 really may not benefit from it as much as the longer stroke GTS would) I would have to think that you should get pretty close if to 400 RWHP if not eclipse it slightly.

I know that 5.0L engine may have a once in a lifetime Sharktune, but with the extra displacement (A stock GTS mind you makes near +60 ft/lbs of torque over an S4!) and the larger valves I think its possible.

I would plan to upgrade the intake to the Blackbird (assuming they do make +15hp as has been documented already) as well, possibly add spacers to the intake, maybe bore out the throttle body a bit too. I have to imagine all those things could sure get you close if not over 400 RWHP.

These discussions are the best for me, DAMN, i wanna get that damn car i have my eye on NOW!

potsiewebber

While we are on the subjest, sort of, does anyone know what the 93 rods can handle hp wise before they give up?

S4ordie

Rob Edwards experience and those of others would indicate "less than stock".

cobalt

That's a bit extreme. There have only been a few documented cases of them failing and in each case it was under less than ideal conditions.

S4ordie

Hmmm, though a noob to 928's I have read enough posts about about 93 GTS rod weakness to make me think there are a number of issues with that engine in general that makes it, for me, an unlikely base platform for power adding without some significant work to strengthen and improve oiling. I can tell you I would not bump the hp up to 400 on a bone stock engine with 100k miles on it.

I don't think Rob's engine failure was "under less than ideal conditions". He was traveling at moderate highway speeds.

Not trying to bash the 93 GTS engine here, just saying there is enough evidence for me to think I would not add power to it.

hacker-pschorr

I cannot help but think detonation is a part of this. The oil ingestion issue with the GTS points in that same direction.


The damage was there long before the catastrophic failure.
If detonation is part of this equation, it's a hammer smacking that piston over and over......it will take time for anything to actually fail.
Which is why I cringe when I hear people say "only a few knock counts" when shark tuning a 928.

My 944S threw a rod bearing while sitting in stop / go traffic.

potsiewebber

I have 97k on my 93 GTS and have had no problems yet. I would love to supercharge it but i know it would not be a good idea

Rob Edwards

I was being a bit disingenuous with my post- It's not fair to blame the rods (as a primary source of failure, anyway) when that motor had hammered its #2 rod bearings into oblivion either due to previous on-track-related oil starvation, detonation secondary to oil fouling due to the lack of oil control ring drain holes, or whatever. Not the rod's fault I was too dumb to turn the motor off before the vicious rod knock I'd heard turned into more ominous noises.....

That said, Greg has mentioned (though I've never seen it firsthand) some cryptic TSB from Porsche saying something to the effect that if you change at least two connecting rod nuts on a GTS, you should R&R all eight connecting rods. That plus the huge # of R2 rods still available from the factory makes one wonder how much faith the factory had in the R1 rod design.

As a semi-non-sequitur, I was looking through my other 928 TSBs and found this one (below) This give anybody chest pain? It's from May 8, 1990, so hopefully everything in the supply chain now is ok.

Rob Edwards

I found the other TSB- remove a nut, then completely rebuild the engine:

cobalt

To be honest, as is with most Porsche engines they can only handle so much of an increase in power before threatening the longevity of the internals. I would agree with you that the base 93 connecting rod GTS engine is not ideal for High hp applications without doing internal changes. I would not say they were not capable of handling the factory power output. I would also suggest that this goes for most Porsche engines and although some like the extra kick of a supercharger on a GTS IMO the car is perfect as is if running correctly. I would probably look into rebuilding a higher mileage engine long before adding a supercharger. This in itself might improve the experience.

The 928 is a car with creature comforts something Porsche stayed away from with their other models. If there were a way to bump power to 400BHP without supercharging IMO that would be ideal and would probably find that more people would be happy with the added 50 hp.

I find it interesting that the TSB refers to 944 S2 and turbo rods also. I know they have far less issues than the 928 rods do and the S2 has no known issues but that is probably because they are at their power limits from teh factory.

slate blue

By Cobalt Anthony would you mind sending that GTech file to me at ggray1964 at yahoo.com as I have a file of my car I would like to compare it too. Same time but different speed, we both have 5 speeds.

Cheers Greg