Vince964T

Hi guys.

Long time since I was on here, had to change username (Vince5 before for those who remember) since I lost my password, changed email etc..

I am considering a swap of the original turbo to a K29. I would up the pressure from 0,85 to 0,9. The car is a track only car with a lot of go fast mods but the engine is pretty stock (pressure at 0,85, race cat and that's it really) and has been extremely reliable over my 7 years and 70 000kms of ownership. Probably well over 100 track days and some races and craches... poor thing ;-)

Any of you guys have some experience of doing that swap. How does it impact the turbo response, anything special with the conversion ?
I know a lot of you have reworked versions of the K27. Anyone with a K29 ?
I have a 6 speed 993 gear box so right now turbo lag is not a big issue.

Thanks a lot !

Sal 965

I've got the K29 in my 3.6 car. The only thing i would say on my set up is the car is quite docile up to 3200/3300rpm when it really gets going.

I'd be really interested to hear how you get on with one with a 6 speed box.

maverick

I went with the K27 HF. My mechanic told me that the K29 is better suited for a track environment where you can keep the revs at 5K. On the street the lag is significant and trying to keep at 5k is not realistic. I have the 3.3 so it may be different for a 3.6. The K27HF is amazing and worth the upgrade. Anyway just my 2 cents worth.

Vince964T

Steve - I get along with the 993 gear box really well, I have had it for 2 years. Kept the original gear ratios of the 993 and it fits the 3,3turbo perfectly. Together with the race cat it more or less removed the turbo lag. My engine is close to stock and so far the gear box has not had a problem to cope even on long sessions of 40min+ (after that the gas tank is empty so it's the max you can do anyways !). I have even heard of teams running these gear boxes in some endurance series with cars more powerfull than mine. I also tested mine going all out on a gear box killer jump on one of the local race tracks, it passed the test...

On some tracks I win a LOT compared to the 5 speed trans, better engine response, no need to get down to 2nd gear. On some others the gearing became less optimal. You win some you loose some but overall I did become faster once I got used to not accelerating as early as I used to. To get around the turbo lag I used to accelerate to the max to get the pressure going as soon as I was done breaking usualy entering a corner. Then I would relax a bit on the accelerator when the power finaly came during the turn then on again when I knew I had the corner approx as I wanted it. Now it drives like a normal car i.e. no need to accelerate so much so soon (I kept doing that since I was so used to it and just understeered), you can be more progressive or can steer with the gas pedal more easily. Overall it makes the car easier to handle and faster I am sure (well I have the lap times to prove it)

On the street the car has lost a big part of the fun factor of having the turbo spool so brutaly. So yeah it has lost a bit of it's special character.


Ok if it really gets going at 3,2 / 3,3 rpms that sounds fine. Sweden has twisty old tracks so I sure can't keep her into the 5k + range all the time like Maverick's mechanic suggests. That would not work. But 3,2 3,3 is Good it's usualy as low as it gets.

Steve what other mods do you have so I am sure we compare apples to apples ;-)
I also have a light weight flywheel, that helps a little.

I am a bit apprehensive ot cranking up the turbo pressure though even if it's not much (0,85 to 0,9). She is old and has 120 000 kms on the clock with a lot of track time but heck it's geting harder to deal with the new GT3s and I am not done with her just yet

Thanks a lot guys.

Staffan

Hey Vincent, long time no see!
Looking forward to some more of this:
http://www.youtube.com/watch?v=ZfxS6guycJA
(Vincent in front of my car)

Need to deal with my gear box first though.
Sorry for OT

maverick

Vincent, Im running 1 Bar and also have the LWFW and clutch but only 52K miles on the clock. I am going to add the Tail waste-gate to complete the package.
Thats a pretty impressive wing your running

cobalt

The K29 is ancient technology. Good only for track use. The HF versions of the K27 do everything a K29 can with full boost by 3200 rpms and blow strong all the way to redline.

Don't forget these cars came with as much as .87 bar of boost from the factory and the turbo S was at .9 bar. So long as you don't have any boost creep issues and have adequate AFR's 1 bar is not an issue.

turboholic

keep in mind that you will have a much more linear powerdelivery with a HF turbo. If you want to keep the "turbopunch" HF is not the way to go. the car will drive more like a N/A car with the HF turbo installed.

911addict

I had LWFW, headers, decat, HFS with Tial w/0.9 spring. The car was streets ahead of standard 3.3, and friends with 3.6 and 355 were all amazed. Delivery very linear and great response (no added top speed though - strange).

Not sure whether more fun, and quicker low down with a standard k27, would love someone to try that combo out and feed back.

Vince964T

O yeah more of this please !!!!!!
2008 season was the best fun ever. Managed to find someone to drive "agaisnt" each and everytime. Since we are so well matched Staffan it would be the same for you.

To bad I sold my gear box or you could have borrowed it. But well guys I MADE MONEY on my car, can you beleive that ! Sold my turbo gear box at a higher price than what I paid for the 993 gear box ;-)

Vince964T

Those of you who drive with 1bar, how much do you track your car and how much respect do you have for her ?

Just want to get some reference, not sure there are that many 964turbos around with as much track time as mine and with very little respect for the poor car...

EDIT - Well there is Staffan of course ;-)

cobalt

I don't track my car. I use the C2 for that. The turbo is a street car only and can handle the small bursts of boost. I also monitor my AFR's and run slightly to the rich side as a precaution. I know of a few turbos running 1 bar on the track and have had a good long life. I know of some that run stock boost and blew their engines in 20k miles.

You run any of these cars .85 or 1 bar on the track and eventually something is going to give. Running temperatures and monitoring your exhaust and boost temps will help prolong life also.

Vince964T

I am basically not monitoring anything...Well air/fuel ratio but only at idle and I am always paranoid thinking the engine is running lean.

Regular maintenance, pretty stock engine and on average cool swedish temperatures (don't laugh I am 100% sure it helps) have been my "insurance" for a long engine life, but as you say someday something will give.
When it eventually happens I still will have the satisfaction of having run the car for a long long time with really no down time related to mechanical problems.

I ll check some prices and I think I ll go for it. I can always go back to the K27 if I am not happy with the lag of the K29. K27HF is may be good but I am far away from Imagine auto so I cba !

I ll let you know how it feels afterwards. May be time to start filming again

cobalt

I certainly agree a tracked turbo needs closer supervision than a street car. Your temps are probably helping you as you say although it is still a crap shoot when it comes to pushing these cars hard. I find I use a 1:3 ratio. Every one mile on the track I equate to 3 street miles. So if i change my tranny oil every 15k miles on the street I change it every 5000 of track mileage or once a year. It adds up but IMO doesn't hurt to keep on top of.

I was especially impressed how you did that disappearing act in the middle of Staffan's recording. Never seen a turbo move so fast it just faded away.

Vince964T

that was the only way ! I could not shake staffan off me so I hit my special IWIN button (it's a secret, I will never tell what it does haha!)

But he cut the best parts off, when he gains 10 car length on me all of a sudden as my mobile phone went flying through the car at the end of the straight and when he drops 2 wheels of the track as we turned the heat on ;-)

We are really well matched, he has a stronger engine but my car is easier to drive