3.0 16V engine mods, etc

[Bergerac]

Jumping back into this car after enjoying others with far less punch is always a surprise and opening the throttle to run at only atmospheric pressure whilst casually cruising in 5th brings the speed from 60 to 100 mph in the effortless and comfortable manner of a jet about to take off, suggesting the larger turbo flows just what the head needed to show its true colours even at the lightest loads, making the car not only a rear tyre executioner but the ultimate long distance cruiser. It may sound like a hyperbole but it really creates its owner weather and you better be on it when you open the tap.

I certainly agree with this, even at only 9psi the car has instant torque nearly everywhere as the turbo spins up. It drives like some kind of insanely fast reving V8. Cant wait to wind it up to 18psi.

[Thom]

Cant wait to wind it up to 28psi.

Fixed it for you...

[Bergerac]

Not all of

Cant wait to wind it up to 28psi.

Fixed it for you...

Not all of us have sexy closed decks

[Thom]

It is turbo weather at the moment with ambient temp a little above freezing with the sun shining pretty nicely for the season. I was able to improve gear changes and work around the lack of progressivity of the new clutch disc by softening the overrun fuel cut which was too sharp. It makes a world of difference in drivability though still not quite as easy as with the previous 930 disc as the biting point in the pedal remains too high for my liking. In retrospect I suspect the springs in the previous clutch disc may have taken somewhat of a beating considering how seamless gearchanges were with the same abrupt overrun fuel cut settings.
With roads on the edge of freezing I did not feel brave enough to open the throttle wide but at only 50% and 22 psi the same IC hose popped out again at the end of 4th gear. This is getting irritating and I will have to find stronger clamps.

[Tom]

It is turbo weather at the moment with ambient temp a little above freezing with the sun shining pretty nicely for the season. I was able to improve gear changes and work around the lack of progressivity of the new clutch disc by softening the overrun fuel cut which was too sharp. It makes a world of difference in drivability though still not quite as easy as with the previous 930 disc as the biting point in the pedal remains too high for my liking. In retrospect I suspect the springs in the previous clutch disc may have taken somewhat of a beating considering how seamless gearchanges were with the same abrupt overrun fuel cut settings.
With roads on the edge of freezing I did not feel brave enough to open the throttle wide but at only 50% and 22 psi the same IC hose popped out again at the end of 4th gear. This is getting irritating and I will have to find stronger clamps.

I hope I didn't give you a bum steer with the Southbend clutch. I fear they have completely changed their disk material since I tried their 'feramic' disk back in the day. Hopefully a combination of tuning and break-in will make it feel a bit more civil.

Undeterred by the possibility of giving more bad advice, have you considered Wiggins clamps for the IC pipes? They take less room than a t-bolt clamp and boost braces, and are truly the ultimate coupler for intercooler pipes -- good enough for F1 racing, jet fighters, and human space flight. Only downside is that you need to trim the pipes and weld on the fittings, but they will never ever pop off or leak once installed. (There are oodles of 'clamshell' knock offs these days by Vibrants and others, but given the effort to install I'd go with the true Wiggins clamps...).

If you are not up for that kind of fab work, the other thing you might try is enhancing the bead on the pipes --especially if the hose is mostly slipping off the pipes and not off the intercooler or throttle body. Vibrant sells a cheap bead roller for this (and now there are cheap knock-offs) which you could use to make your beads bigger still. Thinner-walled couplers also help.

[Thom]

No worries re the clutch disc, I am pretty sure it will hold the torque and I can put up with the slight judder in city traffic. It has done 600 miles already so I think it will be durable, fingers crossed.

Thanks for the info on the clamps. The hose pops off from the IC inlet and there is little room/access to increase the size of the bead which is just a little bit thinner than on your IC pipe. It worked with the previous turbo so I will try a stronger clamp before I need to take the IC out which I really don't want to at this stage.

[Thom]

It is beginning to dawn on me that what I took for a loss of traction mixed with the smooth/progressive nature of how the OS Giken LSD worked was in fact valve float kicking in at around 5500 rpm when running more than 18 psi of boost. Stock 16v springs were not going to perform otherwise I suppose. It just doesn't make sense that a 044 fuel pump runs out of flow under the conditions experienced so far, and if valves do not close properly then there must be loads of fuel wasted into the exhaust.
I can't say I'm in a rush to investigate this as the car sees 95% of its use at legal pace with zero boost. Definitely pathetic but that's how it is.

I have been talking with Cat Cams about stiffer valve springs but interested to hear about possible other options. Any suggestion?

[cda951]

No worries re the clutch disc, I am pretty sure it will hold the torque and I can put up with the slight judder in city traffic. It has done 600 miles already so I think it will be durable, fingers crossed.

Thanks for the info on the clamps. The hose pops off from the IC inlet and there is little room/access to increase the size of the bead which is just a little bit thinner than on your IC pipe. It worked with the previous turbo so I will try a stronger clamp before I need to take the IC out which I really don't want to at this stage.

The 993 Turbo has a terrible design for its boost hoses between the turbo outlets and intercooler, the hoses will pop off even with a 100% stock engine and boost pressures if the hoses and clamps aren't positioned properly. Increased boost pressures exacerbate the situation---I was turned on to these Breeze hose clamps a while back, and they do a good job in my limited experience with a few 993TT running higher boost pressures. Worth a try if unwilling to go full Wiggins .

https://breezehoseclamps.com/breeze/constant-torque/

We ran into the same issue with a customer's modified 991.1 Turbo, the main hose to the throttle body would pop off. Porsche came up with an updated hose that uses an interesting spring-loaded clamp, also seen in Macan and other applications as shown in this link:

https://www.pelicanparts.com/More_Info/ ... KeEALw_wcB

[Bergerac]

It is beginning to dawn on me that what I took for a loss of traction mixed with the smooth/progressive nature of how the OS Giken LSD worked was in fact valve float kicking in at around 5500 rpm when running more than 18 psi of boost. Stock 16v springs were not going to perform otherwise I suppose. It just doesn't make sense that a 044 fuel pump runs out of flow under the conditions experienced so far, and if valves do not close properly then there must be loads of fuel wasted into the exhaust.
I can't say I'm in a rush to investigate this as the car sees 95% of its use at legal pace with zero boost. Definitely pathetic but that's how it is.

I have been talking with Cat Cams about stiffer valve springs but interested to hear about possible other options. Any suggestion?

Ive used the Catcams springs/retainers, I didnt find any other options out there that didnt require custom parts. They are a BMW size so maybe you can use the Cat retianers and find springs elsewhere.

Are you using stock valves as well?

[Thom]

Yes, stock valves here.

How much boost and how far high up have you pushed your engine yet?