Green Track Cup - Back To Basics

[neil a]

Looks like the track day on Friday will have to be cancelled , took the car for a quick test last night after fitting the suspension and changing the box oil and sounds like something has f@&ked up with the diff.

Who is best to use for a box rebuild ? If i send the box to Agency Trans will they strip the box and send the diff to Gripper for service/inspection ?

 

[BIGASH]

What's it doing Neil? I'm sure you know how noisy and broken sounding gripper Diffs are? What oils it on?

 

[neil a]

Its locking a wheel even at 10mph as soon as the wheel is turned, not just clunking its almost stopping the car.
Ive ran gripper diffs before in my cosworths but they are separate diffs not in a gearbox. I have done a track day with this box fitted and it wasn't too noisy before, last night it defiantly sounded like something failed to the point i had to push the car back into the garage. With the car jacked up and no load there is no noise or snatching.
It was on Castrol B373 but changed to Morris XFS 80W-140 that was recommended by someone that also runs a gripper.

 

[Martin.]

s**t that doesn't sound good :-(

Hopefully it's nothing too serious

 

[neil a]

I do have a spare standard box I could put in but alot of messing about for one track day, would rather hold off and get the gripper box checked/rebuilt.
Fraser is coming along tonight to give me a hand pulling the box out.

 

[p@blo]

This looks great. Bit of a shitter about the box problem so close to its next outing. Hopefully its nothing to expensive.

 

[Tomotek]

Great Thread.. Got me through the last hour at work :wink: .. Hope mine turns out as well as yours!

 

[neil a]

Thanks glad it helped you pass a bit of time :smile:

I have done a few quick calcs before raising the rev limiter from 7500 to 7800 or changing the 5th gear ratio to be more useable.

On the gearing i'm on jut now upping the limiter only would mean the top end of 4th would be 109 mph up 3mph , justnow im hitting the limiter in 4th around 150m before the breaking point so not sure if this would be enough of a rise.

Leaving the limiter at 7500 rpm but changing 5th gear options are

Just now with the standard 31/39 5th gear the revs drop from 7500rpm to 5800 during the change from 4th to 5th at 7500 rpm topping out at 138mph

With a 33/37 5th ratio that would become 7500 to 6500 on the same change topping out at 123mph

with a 31/37 5th ratio that would become 7500 to 6100 on the same change topping out at 130 mph

Im looking forward to seeing what some of the class D cars top out at during the first SLS race this weekend as I think this will be the group I would end up in , my thinking is upping the limiter may just be enough to let me just use 3rd 4th for most of the track bar the hairpin.
While the box is in bits for a rebuild would it be stupid not to fit a shorter 5th as I do hope to go to some other circuits at some point and 5th will then be needed.

This is my last power run done at Sitech a few months ago after a map tweak.

The decrease in rev drop from 5800 rpm to 6500 , would mean I have around 25whp more after the shift.

Also the engine is still holding onto power at the 7500 limiter so hopefully wont drop too much if I up it to 7800.

 

[MG cup]

Do you have a lower FD already Neil?

If I'm honest I found the standard ratios in the cup just right for KH with the 195bhp in my ITB'd cup. I was really buzzing the engine along the straight to carlube in 3rd when pushing and just about buzzing 4th coming into duffus. With your thing having what another 45bhp on mine then leaving things standard ratio wise and then lowering the final drive might be best... That way you get good use of 5th into the hairpin and duffus, plus it keeps the engine safer.

 

[neil a]

Hi Morgan my box has the lower 4.615 gripper FD fitted. I found the car faster out of corners with the lower FD , the only problem is im now hitting the limiter just before the breaking point heading up the straight and towards the hairpin in 4th.
With the big drop in revs between 4th and 5th on standard gearing it was a toss up between changing to 5th and dopping out the power band or hit the limiter and back off.

 

[MG cup]

Remind what speeds that gives you in each gear? Could you go lower in the FD again or did you risk spinning everywhere other than on the hottest of dry days? Terminal times down each straight is more important than off the corner really in the time attack style arrangement that you plan, speed off the corners will be better suited to door to door racing and getting a launch from undercutting etc. KH has just had sector timers And speed traps installed I'm told too so will be good to compare amongst cars.. Not so much of an aid for you with the car in bits but if you had that data you could adjust to suit.

 

[neil a]

Justnow the car pulls through the gears with no real drop off in power but on the change to 5th , there is a noticeable drop of. By changing to a lower ratio 5th I could change up into 5th earlier on the two faster parts of the track.
This then adds in an extra gearchange and with the pure shifter I find the 4th to 5th change quite notchy, I just don't know if upping the limiter 300 rpm will me to just use 4th or if I will still run out of revs before the breaking point.

Justnow this is the speed per gear and drop between changes
1st 35mph @7500 rpm
2nd 58mph
3rd 83mph
4th 106mph
5th 138mph

1st -2nd rev drop 7500 - 4500 rpm
2nd - 3rd rev drop 7500 - 5300 rpm
3rd - 4th rev drop 7500 - 5900 rpm
4th - 5th rev drop 7500 - 5800 rpm

 

[MG cup]

Given what you have said.... Get the 33/57 5th and start using it a lot earlier than you would. You have good power on tap from 5k. If that's not right then just up your limiter?

The 5th gears are what... £60? Anyway which ever way you go I'm told the 5th gear swap isn't the biggest of jobs and something you could easily manage in the car.

 

[Mini182]

5th gear swap can be done with the gearbox still in the car.

I have 3 different sets so can use different ratio's at different tracks.

 

[neil a]

Thanks a lot I will get CTS to fit a 33/37 5th and get my originals back as spares.
When I get back to the UK I will have 1.5 weeks to get ready for my first event, really looking forward to it . New suspension is fitted so need to re fit the box, get alignment, then get an official power run and weight check to find out what class i'm going to have to run in.
Actually hope the car makes a good bit less power on the official rollers used for SLS , that it has in the past on Dastek and Mainline dynos as if its above 160whp/ton then I will be in class D, which just now is full of Evo's, Scoobs and M3's

 

[NorthloopCup]

5th gear swap can be done with the gearbox still in the car.

I have 3 different sets so can use different ratio's at different tracks.

That's not a bad plan right up to the point that you encounter the splined 5th gear not playing ball and not coming off the shaft. Every single box I've stripped, the 5th gear has been a pita to remove. f**king things! Lol!
I did consider doing it the very same way though, so original 5th for ring trips to gain some sort of fuel economy, then swap to Meg on arrival.

 

[sonny172cup]

We fitted the 5th while box was in but the black end cap of the box wouldn't come off fully so had to bend the inner wheel arch slightly, not sure if this was due to solid mounts or not.

 

[Mini182]

That's not a bad plan right up to the point that you encounter the splined 5th gear not playing ball and not coming off the shaft. Every single box I've stripped, the 5th gear has been a pita to remove. f**king things! Lol!
I did consider doing it the very same way though, so original 5th for ring trips to gain some sort of fuel economy, then swap to Meg on arrival.

Yeah that is normally the case. My 5th gear shaft has been smoothed off slightly to make this easier though, still can be a PITA though.

@sonny172cup We normally just remove the gearbox mounts and support it on a jack in order to drop the box slightly, this make's it easier to remove the end cap. I didn't even know you could do the 5th gear on the car until I saw it in your thread a while back!

 

[sonny172cup]

@Mini182 fair one, cant remember reason why we didn't do this now. So you use 3 5th gears, isnt that a tad excessive? Is that due to the final drive of the Gripper? (Did you source a 172 cup box?)

 

[Mini182]

@Mini182 fair one, cant remember reason why we didn't do this now. So you use 3 5th gears, isnt that a tad excessive? Is that due to the final drive of the Gripper? (Did you source a 172 cup box?)

Yeah it's because of the gripper FD. I'm just using the PH1 box, the only difference between that and the cup is the FD anyway.

I've got the standard 5th (39/31), a 37/33 and a 39/32. They are not that expensive and should cover me for all tracks.

 

[neil a]

Home in a week and had the plan of getting the box back in the car, alignment,weight and power run done asap, to hopefully get a track day in before entering a SLS race but not sure if plans are going ot work out.
After CTS having the box for 3.5 weeks, having it stripped for over 2.5 they were just today building it back up and found a crack in the casing :rage:, so Bernie is going to see if that can get welded if not I will have to wait until im home and send a spare box down. On the plus side the diff has been refreshed and now have shorter 5th gears fitted.

 

[NorthloopCup]

I have a spare set of casings mate.

 

[neil a]

Will keep that in mind Mark thanks, still not heard back from CTS to see if they managed to weld mine

 

[NorthloopCup]

Will keep that in mind Mark thanks, still not heard back from CTS to see if they managed to weld mine

They're quite awkward things to weld tbh mate. Normally the heat from welding causes tension elsewhere so they crack again. Need em in the oven so everything's at the same temperature.

 

[BIGASH]

Yeah I had a box welded a few years ago and it lasted no time at all

 

[neil a]

Well casing was welded but cracked again during reassembley.
Anyone near Hertfordshire have a some JC5 129 casings or a cheap box.
CTS are going to get a price for new casings but expect ££££ for that.
I don't even know what section of casing it is yet to so not sure if it has to be a 129 or if any 172 box would do

 

[neil a]

New gearbox casings are now on the way to CTS thanks to Northloop (Mark) .
Today i received my last fg panel in a new tailgate from Chris at CMC, so now have his doors ,tailgate and roof scoop , so hope to get that dropped off for paint at the start of the week along with a centre console for the porsche.

 

[neil a]

I got my fiber glass tailgate fitted and painted today , only a small saving in weight over my gutted standard part but every little helps. With the passenger seat removed and my lighter wheels I would think the car should now weigh 900kg with fluids.

 

[sonny172cup]

Looking spot on mate

 

[Mini182]

Looking good.

How you getting on with the gripper problem? Seems like you have had a similar issue to me.

 

[neil a]

Having a bit of a nightmare with the rebuild , the gearbox shop noticed a crack in my outer casing and had issues trying to source the correct casing. I'm hoping to have the box back soon , they didn't find anything obvious with the diff but have re plated it and checked preload.

 

[neil a]

To cheer myself up about still not having a working car I bought myself a new skid lid today , also got myself a alpine star suit.

 

[NorthloopCup]

^^^^^^Nice!! Bet that was cheap!

 

[neil a]

I wish it was Mark, wasn't planning on spending much on a helmet but seen this and though I want lol

 

[Fletcher]

Liking the new boot!

 

[Carbonraider]

Loving the new lid I have just bought a similar stilo item. Still can't believe the box situation hope all gets sorted soon and you get back out on track.

 

[neil a]

Either can I its getting beyond a joke that's over 6 weeks , even giving the time waiting for the 5th gear and sourcing a new casing I think that's a joke.
The part that's annoying me is they messaged me while I was in Malaysia asking for a serial number to order a casing and I explained that the box wasn't original to my car but it did come out a late 2003 cup. They then left it up to me to try and source another casing but when that turned out wrong I then had to call agency trans who told me what casing I would need. After that inf was passed to CTS they called a place that they deal with and a new casing was sourced in a day. Why they couldn't have dealt with that 3 weeks ago buy sending a picture to the companies they deal with I don't know.

 

[neil a]

Gearbox is back in with new 5th, 3rd syncros , shorter 5th ratio and re built diff. Hope to get alignment done on Monday. I'm book on track on wed but if I get alignment done I will book Monday night aswell.

 

[NorthloopCup]

Gearbox is back in with new 5th, 3rd syncros , shorter 5th ratio and re built diff. Hope to get alignment done on Monday. I'm book on track on wed but if I get alignment done I will book Monday night aswell.

Which 5th have you opted for mate?

 

[neil a]

Went for the 33/37, will be interesting to see if I end up using it on track or if upping the limiter a little to 7750rpm and holding 4th will be quicker.