Oooooh!

Oops...

Anyone got a tissue?

I have lost the coil packs.....dont trust them....I now run 2 coil packs which are made to work with the ECU and run leads (magnecor) and being an 8 I have the VVT which operates at 1500rpm and programable on my ECU so no probs there.

Feel free to come and have a nose around any time

Avos, the motec ECUs are a complex bit of kit, probably about the best of management systems available which reflects in the price.It would be great to use either motec or Life racing ECUs but it would simply price our systems to high. I have used both in the past, but both are time consuming to program .However they are very good.Even then , with these I have used DIS packs in the past. The problem with individual coils is the recharge time and getting the right resistance coils to run.I use Omex here,they are a very good value ECU , easy to program with easy to use software. However you will find many of these suppliers leave the garage to do the development work. I use Steve Greenauld for my rolling road tune. He has been around forever,a kind of Guru .I`ve never seen him stumped, though our Lotus Elan caused him all sorts of problems on individual coils, on the rollers under load.
In lowering the coil recharge time we unfortunetly reduced the power the car was developing, but it did cure the missfire issues at higher RPM. We found this out ourselves programming the car on the road.No reason for this to happen, but we established it must be a softwear trigger issue.If it had been developed further we could have saved a huge amount of time tuning, which my business had to absorb.
I feel many ECUs cannot run a broad selection of individual coils effetively Care has to be taken to select the correct resistance. Then consider plug resisitance and how Hot/ cold plugs react to that fat spark under load. No rules , just trial and error and list your findings.
Running DIS packs (which we do on all of our conversions) you naturally run plug leads which have an inherent resistance, so there are few problems on the whole, but if your pocket will stretch go for the Motec, expect a big bill and expect an even bigger one on the rollers, but you must do your research on those coils though if you go that route.
Don`t forget the golden rule, tuning is like cooking, leave out some of the ingredients and the dish becomes a compromise.
You still need the cams compression, porting, valve shape, dry sump etc etc to get the absolute most out of your management system.Hope this helps, have a good weekend.

Thanks for the feedback, and I see your point regarding the coil packs/ECU type and efforts needed. Working with someone who has years of experience in Dyno/Tuning is indeed very valuable, even if they know less about the more modern cars with all the electronics, basic engine knowledge stays crucial for proper tuning.

Fully agree with the cooking analogy, have learned that also the hard way, going for the max requires serious knowledge and also knowing what you are doing to and understanding the full design you want to achieve. Nevertheless it is fun tuning cars imho, even though you miss some knowledge here and there, and even greater that people share experiences ;-).

For know I work together with some one that is also able the program the modern Denso ECUs from our cars, unfortunately not inexpensive either, but at least you can keep the full car electronics.

1 use the bell housing from an XK, they unbolt and can be fitted via an adapter plate.

2 and 3 Use an Aston Martin flywheel and clutch from an AMV8

Or you go the really expensive way and have one made, you will also need a twin plate clutch as the bell housing is so small.

Simples

You might of looked at an XK8 box as apposed to the Merc ZF XKR box which the bell housing is removable.

I made my own flywheel and clutch (OK AP racing helped a big bit with the clutch)

What you do have to bare in mind is the diff ratio 3.09, it would be handy to get a manual box that works with that otherwise it is another expensive route, having a crown wheel and pinion made.


The Aston flywheel and clutch will work, you could even use the gearbox if you wished, I beleive it is the same as mine a T56, but like I said you will have to play with the diff to make that work.

Hmmm spares....I think not...

If you go to AP be prepared to pay £1000 for the clutch, the flywheel I do have a darwing for, but again the Aston will probably be cheaper, unless you have access to a large(ish) lathe.

I also fitted the timing ring and starter ring from the original fly plate into my flywheel.

What gearbox are you going to use? I chose a T56 as I was offered one from a Dodge Viper Leman car compete with release bearing, what you need to remember, I did all this 12 years ago long before Aston or even Jag did the XKRR. It will be much easier for you just to buy the parts and make them fit as at least you do have a parts source for any other issues you might have with them.

Did you have any problems using said gear box and accomodating it in the tunnel of the shell? Are most of the things said applicable to the X308 XJR also?

There was a little 'jiggery pokery' involved, did not have to alter the tunnel, but had to extend the posistion of the hole the gear stick went through, you can get over this when making the gearbox mount and changing the way I did my gear stick. I did mine remote straight off the top of the box, but it is possible to move the stick back on a fabricated mount and have the change coming out the back of the gearbox instead of the top.
I am unsure if the same setup would fit an XJ but if you assume a 308 has the same setup as the XK, then you can only assume everything will fit the same.



Have fitted XJ diffs already and they simply are not man enough for the job, they will work fine when rolling but from a standing start, would not last that long at all, you also have the prob of the nose of the diff being off centre where as the XK is inline, if you was to do it in an XK8 you would need to fit a XKR 2 piece prop as a minimum, otherwise it will rub.

I did not bother trying an XJ diff for my car, it will not last, unless Hewland builds it for me at a cost of £5K......Think I will pass on that one, I will be happier with a quaife and my own crown wheel.

I do know someone who has fitted an XJ diff into his manual XKR, can't remember what ratio he has? I think it's a 4.0, but he is not planning driving like an utter lunatic around a track.