AO

I went with all NS.

Tony

[QUOTE=mark anderson;8392102]what did you do with the propeller?

AO

[QUOTE=Tony;8394761]Tony, that's a boat propeller. It won't make cars fly.

(Damn pilots always afraid of a little competition.)

OBehave

I use half NS and half regular in my 85 track car and everything is happy now.No noises or issues.Of course I don't have 600 hp in that car, but I am going to follow this fix that Mike is working on very intently because I have basically the same set up in the Hanson racer as John has just blown up!

Benton

So you go 4:1 and Devek said 1:1? Confused with that, but thanks for the input. Edit: Ed, just saw your post, thanks for the input as well.

I'm also confused as to what you are referring to with the RPM match as the engine speed does not affect the input shaft speed when the clutch is disengaged--for instance, when downshifting and blipping the throttle, clutch is obviously disengaged.

I'm pretty proud of my rev-matching heel/toe skills (I know you don't heel/toe, but that is another subject for another day), but the gearbox has gotten up there in mileage and we have since had to double clutch on downshifts to alleviate the crunching (which matches the trans speed with engine speed). When my dad drives the car, he skips gears on downshifts and just waits until the end of the braking zone to blip into the necessary gear. While I know it is a little tougher on the 'box, I "row" through the gears on downshifts--just the way I prefer to do it as it feels right and keeps me in rhythm. But it gets a little tiresome double-clutching on every downshift. Back straight at Road Atlanta = 6 pumps of the clutch pedal to go from 5th to 2nd in a very short period.

Luckily, I have a low mileage gearbox that is going in at the same time as the LSD, along with a cooler. Track car v1 was great and we beat the crap out of it, but it's time for v2 with some reliability revisions on the engine and trans so it will be race ready.

A little OT, but still along the same lines of extending the trans life.

James Bailey

Kibort just likes the sound of the throttle blip but it does reduce the engine braking effect as you drop down in gears while engine RPM is higher allowing for downshifts in the corner. And I too need to double clutch into second with the old very brown 1980 and always heel/toe with my size 14 ... Driving a 1947 Plymouth with a none sycronized first gear teaches you a lot about shifting and with the VW bus I got pretty good at downshifting without using the clutch.....why just because I could !

John Veninger

Street car I do 2 NS and 3 regular.
Track is NS with one qt of regular. Think I use a total of 6 or 7 qts due to the cooler and pump.

John Veninger

It did hold for a few years.........

mark kibort

yes, i went even more on the NS, probably would go 100% if I knew the logic with going half and half from the beginning. (just trusted their advice)

anyway, as far as hard blips. let me see some video of your "crunchiness" Like I said, mine got very hot and very crunchy before I started with the real heavy gas pedal blips. it would happen near the end of the race. it would be crunchy, but the races were races and I didnt care. thankfully, the gear box survived, nothing was damaged and in '04 when I really started to drive the trasmission better with this technique, SUDDENLY, there never was cruchiness again!

rpm match with the clutch in, is matching the rpm that the gear box wants to see, (based on gear and vehicle speed) when you select the next gear. (up or downshift ) the point is, if you have the right RPM match vs the speed of the car and respective gear, letting off the clutch will instantly spin the transmission w torque tube, to the matching rpm. this allows for clutch less downshifts and upshifts, if you are REALLY good. (but not really the same)

why the double clutching? this isnt grampa's chevy truck from 1945!
by letting the clutch out in neutral, you speed the transmission up, but that could be done with just dumping the cutch in the next gear at the right rpm and make a nice fit. post some video. let me know what you are doing.
let me see some of those heel toe downshifts.

I do it in such a way, that when the clutch starts to go in its not all the way depressed until gear goes through neutral, and the blip and press are right in between. probably gives the torque tube a little rpm kick, and the synchros force the gear train and torque tube up to speed as well which is a fraction of the force . I know what you are saying, but its hard to put into words on paper.

yes, the rythym is very important. putting it in neutral, (or missing a gear for example) you will be reving and grinding to find the right match of speed vs gear. your brain is not a speedometer, and its all feel. thats why going through the gears is a good idea for a lot of reasons.

Again, ive been there before. knotchy gear box. i happens when hot. very hot. and under extreme racing conditions, where not much care is happening with shifts. get more careful, you can even get more agressive and the notchiness goes away. like i said, watch scots video with the OB gear box. it was no issue to drive it. 2nd was a little tricky, but i got the hang of it after a few laps.

IcemanG17

I still think part of the answer is gear sets made of stronger alloy.....like what Rockland Standard Gear does in their T-56 tranzillas....stock is around the strength of our 5 speeds...but upgrade is 1000+

However it Simard came up with a fix using stock parts that lasts, and I'm sure Anderson and Mike will test it big time then that is the most cost effective way to go!!

However I still am a fan of the automatic.....and I intend to test it to the limit, once I get enough torque to do it!!!! Hmm....a semi automatic with a clutch up front...just to pass tech inspection and allow for "both feet in"

svp928

Brian just put a locking converter in it....

Benton

Mark, man, I appreciate you taking the time to discuss... but I'm just going to call it quits at this point. Low mileage trans + cooler going into the car, so it isn't really a concern of mine anymore. Not looking to get into a discussion about my shifting technique and how what you do is better.

mark kibort

Thats fine. no problem I just found a way that seems to cure the problem that we all might see on the track with an older or weaker transmission, and I was sharing it with the group. Dont get defensive if your way of double clutching isnt working and you still have notchiness in the trans when it gets hot.

I still want to know why double clutching the 928 transmission would help.
Ive tried it before and it just makes things worse. but maybe im just no good at it.

Benton

Must... resist....

ah what the heck. It appears you did not fully read what I posted before going into your diatribe. I double clutch to cure the problem. It does not crunch when double clutching. OK, now you are allowed to get the last word in, maybe with another unfounded--and perhaps belittling--remark:

slate blue

Can I just add an idea that might be of some use??? The Ferrari 6 speed transaxle in the 599, 575 for that matter is extremely strong and it is the same basic gearsets that are used in the 599XX which has in excess of 700 hp from the factory. The rear end axles should bolt directly up to our axles as they are both ZF and I had someone measure them for me.

What is needed is a new custom case to fit those gearsets into a Porsche 928 friendly casing. So that the input shaft is where we need it along with the gear selector and mounts.

For racing etc many Porsche casings are refitted by Hollinger and Modena engineering here is Oz. So it is not so crazy, just the other way around and I would have thought a casing would be cheaper than gearsets. If it got done for $15 to $20K I would say that is accepatable on the basis that it is what is required for high level power outputs.

Greg