4722 replies to this topic

[Nev]

The OEM standard gearbox (a Getrag F23) is supposed to be a good strong item. However having said that, I imagine stupid use of power in 1st and 2nd gear would break it pretty fast. Even if it breaks, F23's are so cheap on eBay I am not that concerned as you can pick them up from £150. I think what is more worrying is burning out clutches as they are a LOT more expensive (

Edited by Nev, 09 December 2009 - 08:34 PM.

[cheeky_chops]

Is there a specific reason why you asked the question ?

no specific reason, just keen to see the fruits of your labour!

Shall i rephrase the question - when do you envisage each phase being complete?

[vxr36]

As for the Quaife LSD, I will install one if I have any money left at the end of the project !

Nev.

You should definitely have one fitted. If you don't you will see all the power being wasted through one wheel or the other. I had this problem in a straight line and corners were worse.

ETA: Mine is the Plans spec. and I am extremely happy with it. No whining, it just does what it is supposed to do.

Edited by vxr36, 09 December 2009 - 11:22 PM.

[Nev]

Thanks VXR36, I certainly realise the important of the LSD and am aware of the Plans spec one having a slight tweak to it to make it more rear wheel drive compatable. Hopefully I will have enough money to put it in, though a price of £670 for a few cogs and discs is outrageous !

[Nev]

I have spent about 2 hours today modifying a lot of the blog pages with:

o Extra pics inserted
o More detailed write ups
o The costs/parts spreadsheet is now updated and fully online

I am on the verge of spending £4k on parts in the next week or so (*gulp*) and I am determined to go ahead even if I am going to be as poor as a church mouse for the next 6 months

I have now changed my mind yet again, and am going to install solid lifters and get blank ground cams with an aggressive lift/drop mechanical profile. This alone is a £700 option, but means I can revs the bollox out of the engine without the fear of valve float and piston fouling. In theory the parts I am putting in should cope with 9000 RPM, though the turbo/cam profiles I have chosen will run out of puff way before then. I can now see why Stephan Klassen moved from a GT30 setup to GT35, the temptation to install overwhelming power is always gnawing away at my brain, but at the moment I am still aiming for a humble +/- 430 BHP.

Edited by Nev, 12 December 2009 - 01:43 PM.

[VXT Tim]

Keep going Nev

[Sticky]

Thanks VXR36,

I certainly realise the important of the LSD and am aware of the Plans spec one having a slight tweak to it to make it more rear wheel drive compatable. Hopefully I will have enough money to put it in, though a price of £670 for a few cogs and discs is outrageous !

Have you considered a plate diff rather than the Quaife? I've been quoted around £500 but I don't know anyone who's fitted/run one.

Def agree you need an LSD with all that power/torque

[Nev]

Sticky, any idea who makes/sells that plate diff for approx £500? Is Gripper ?

Edited by Nev, 12 December 2009 - 09:13 PM.

[Duncan VXR]

Nev sounds about right for diff price at gripper speak to Jon at Dave mac propshafts - 02476683239 as they have taken over gripper diffs. Spoke to him for one for my M32 box and all fine other than getting the setting correct as you don't want it to aggressive Tran-x are round the corner from me also Nev but never dealt with them, dealt with Jon quite a lot, really helpfull guy and knows his stuff ATB type diff would def help but in fwd cars have never been fully convienced and found torque steer can be interesting and of course when you loose traction fully in one wheel it acks like a std open diff. Plate diff in the same car always felt better imho. Be interesting to drive the 2 different types back to back in a vx - certainly Chris has one in the europa and seems to work for him Keep up the good work Nev DG

[cnrandall]

I run an ATB in mine with the normal ramp angles. Usually I try to avoid putting slippy diffs in these cars as they do cause unwanted handling traits but if you end up with massive torque you really do need one to get the power down. Mine took some setting up and I'll probably change the ramp angles for next year but generally I've been pretty pleased and it does help the lap times. I can supply ATB's and fit them if anyone is looking for a good source and some helpful advice in how to get the most from them.

[Crabash]

If I'm not mistaken the ATB type would in theory loose all drive should there be zero traction in one wheel due to the way they work but they realise this and build in some pre-load to stop it happening. At least thats what I read somewhere.

[Nev]

Farndon rods have arrived HERE as an early Xmas pressy )

To be honest, starting a new job 3 weeks ago has impacted the project, however the new year should be exciting once this weather disappears and I can actually brave going into the frozen garage.

Edited by Nev, 24 December 2009 - 06:48 AM.

[VXT Tim]

Anything else ordered Nev?

[Nev]

I am just making a decission about what pistons to use ATM. Most other bits are already on order from an engine builder I know.

[Duncan VXR]

Nev what are your options? Rods look good, was going to do mine this week but never ordered any in time and ended up with snapped spark plug in head to sort out Can't remember if you were going to lower the compression any further? Are the costworth ones recently released worth considering (upto the power required)? Must pop over when I have some free time to have a good look at progress and if needed give you a hand for a few hours Think my 3071 plans are on hold and just going to do rods / cams and maybe inlet mani and remap for now and concentrate on getting her looking nice (long overdue) 320ish bhp with no lag should be enough to keep me interested for now may make more who knows??? at 310 currently but rods should help raise the revs and not worry about the torque so much, cams - ????? but felt good in Cheeky's car DG

[Nev]

Dunc, Working out dynamic dynamic CR is bloody hard. This is because I dont know: 1/ How much material will be skimmed off the head and block. 2/ How much material I will have to grind out of the piston pockets to allow for 10mm or 10.5mm of inlet valve lift. 3/ Most importantly I dont know how much boost I will use/get out of the turbo. 4/ It is very hard/impossible to estimate how much of the boost pressure will be lost out of the exhuast valves due to cam overlap. 5/ I may put the inlet cam on a vernier pulley which will also affect point 4 above. With all this volatility, I will most probably start with a 8.5:1 static CR piston (assuming fitting a std 1.3mm gasket). This seems high to me and my calculations say this will lead to risky pre-ignition conditions. however if I encounter too much dynamica CR and Courtenays have to retard the ignition a lot while remapping it, I can easily put a Cometic 1.9mm gasket in (or even stack 2 Elring 1.3mm gaskets on top of each other), thus lowering the CR. I have tried getting exact factual info on the new Cosworth Courtenay/PEC pistons. When rung up, neither party could furnish me with exact info that any engine builder would want, specifically whether 260 degress of overlap cam (at std advance) and 10.5 mm of lift would cause fouling of the valves on the piston crowns. I can understand that the modelling of this is complex, but it is important for any engine builder who would want to use these items. On the assumption that I would have to machine them anyway, I see no reason to buying them . I will most probably go for Accrolite or some other piston though I haven't made a final decission. Lastly, I am now seriously considering using a GT30R76, as I dont think a GT30R71 is going to get to 440 BHP. Am also having probs getting hold of +1mm larger inlet valves - can anyone help me with find these please?

Edited by Nev, 31 December 2009 - 02:22 PM.

[Nev]

Just thought I'd metion why the project is stalled at the moment - because I am having a hell of time getting +1mm inlet and +1mm exhuast valves. I am currently chasing Ferrea in the USA for their valves to check their GM 2.2 Ecotec ones are the right size, collet, valve angle etc for the Z20LET - hopefully they will be, as I am raring to get on with it all.

[theolodian]

Wish you'd said, they were at Autosport!

[Duncan VXR]

Nev is there really a need to do that much work with the head? Does Stephan do much with his (thinking of the only other person running mega power)? If you have oe ones can a decent company not copy and spec to the larger size required? Would not think it was that hard tbh Will give you a shout when the cams are in and let you know what they like been speaking with Dave H about inlet manifolds and we have a few options that may help you also been talking with the companies about your piston options and think the 600bhp rating of the new superspec pistons should be just fine Dave getting more tech detail onit) they are also releasing some H rods in the next few weeks that include under piston oil spray (not as good as LEH setup but a step forward CS have purchase the complete stock of cosworth pistons at the moment Also working hard on a new inbox for the crazy ones in the group DG

[Duncan VXR]

Wish you'd said, they were at Autosport!

never knew or would have spoke to them