Rallyrep in action

[tttoptotty]

And as a little bonus, we were both quicker than the R8 by more than 2 seconds .

like it

[Hanuman]

A more than worthy result, especially in light of the huge frustrations leading up to your lap.

And even from down by the last chicane, listening to you leave the line, it sounds fantastic. All chirping and crackling. Evocative of events 25 years previous.

[marcz]

Nice work Tim!

[Nicky C]

The first few Tim has already posted and you may have already seen.
Although Castle Combe is a huge track, there aren't many vantage points for good photos, so they are always a bit samey. But there are a couple that came out really well.


































And Tim pasted this sequence together for me .

[Tim C]

Originally Posted by 20vcqdriver

Don't leave me hanging on a thread... what mods you been upto then, or is it on another thread I've missed.. And who does your re-mapping. Asking as I need mine setting up properly in a few months after fitting the methanol injection

Thought I had better answer this here rather than infect Ian's thread .

Nothing major this year, lots of little things that will hopefully go along way.
Some of which are:

Bigger wastegate and pipework to try and combat the boost creeping up at higher revs.
Some 034 uprated engine mounts (the 90% stiffer ones not the solid ones), it was still on the originals !!

Upgraded the ECU, from Emerald K3 to K6 to enable us to use coil packs. The old K3 didn't have enough outputs to support 5 coil packs. Up until now we have had to limit the boost and revs because of spark blowout. The single coil didn't have enough time to regenerate and produce a decent enough spark for the boost after about 6000rpm, so it used to start missing. Now with some meaty coils on each cylinder we should be able to let it rev a bit further, maybe with a tad more boost .

The main reason for the map tweeking is the result of some inlet manifold balancing. On a jerry-rigged flowbench we found that No.3 was getting less than half the air of the others and No.s 1 and 5 getting more than the other 3. The problem is more obvious at lower air speeds (i.e. low boost) but still evident at higher air speeds (high boost).
So after some very time consuming engineering and re-measuring on the manifold they are now almost even.
As a consequence, No.3 is no longer running rich, so the fueling measured at the lambda in the downpipe (as an average of all 5) shows the engine is now running leaner.
It's not been quite as easy as shifting the fueling map up a bit, but the lambda is fed into the ECU and can be datalogged along with revs, throttle position and fueling map position. So with a bit of driving around, reviewing the datalog graph and adjusting the appropriate fuel map site where it is running lean, it seems to be getting there.

I'm only trying to get it drivable and safe (from detonation) to use next weekend and then I think it'll need a session on the rollers. Up until now we've been up to Emerald themselves for mapping, to see Dave Walker.

With the nice strong spark and all 5 cylinders theoretically getting the right air/fuel ratio and working properly it feels a lot, lot stronger, especially low down pick up .

[20vcqdriver]

Originally Posted by Tim C

Thought I had better answer this here rather than infect Ian's thread .

Nothing major this year, lots of little things that will hopefully go along way.
Some of which are:

Bigger wastegate and pipework to try and combat the boost creeping up at higher revs.
Some 034 uprated engine mounts (the 90% stiffer ones not the solid ones), it was still on the originals !!

Upgraded the ECU, from Emerald K3 to K6 to enable us to use coil packs. The old K3 didn't have enough outputs to support 5 coil packs. Up until now we have had to limit the boost and revs because of spark blowout. The single coil didn't have enough time to regenerate and produce a decent enough spark for the boost after about 6000rpm, so it used to start missing. Now with some meaty coils on each cylinder we should be able to let it rev a bit further, maybe with a tad more boost .

The main reason for the map tweeking is the result of some inlet manifold balancing. On a jerry-rigged flowbench we found that No.3 was getting less than half the air of the others and No.s 1 and 5 getting more than the other 3. The problem is more obvious at lower air speeds (i.e. low boost) but still evident at higher air speeds (high boost).
So after some very time consuming engineering and re-measuring on the manifold they are now almost even.
As a consequence, No.3 is no longer running rich, so the fueling measured at the lambda in the downpipe (as an average of all 5) shows the engine is now running leaner.
It's not been quite as easy as shifting the fueling map up a bit, but the lambda is fed into the ECU and can be datalogged along with revs, throttle position and fueling map position. So with a bit of driving around, reviewing the datalog graph and adjusting the appropriate fuel map site where it is running lean, it seems to be getting there.

I'm only trying to get it drivable and safe (from detonation) to use next weekend and then I think it'll need a session on the rollers. Up until now we've been up to Emerald themselves for mapping, to see Dave Walker.

With the nice strong spark and all 5 cylinders theoretically getting the right air/fuel ratio and working properly it feels a lot, lot stronger, especially low down pick up .

Thanks Have been wondering about the single coil on my 3B when I eventually get money for the upgrade and whether it will cope.

[Isimmo]

Originally Posted by Tim C

Thought I had better answer this here rather than infect Ian's thread .

Nothing major this year, lots of little things that will hopefully go along way.
Some of which are:

Bigger wastegate and pipework to try and combat the boost creeping up at higher revs.
Some 034 uprated engine mounts (the 90% stiffer ones not the solid ones), it was still on the originals !!

Upgraded the ECU, from Emerald K3 to K6 to enable us to use coil packs. The old K3 didn't have enough outputs to support 5 coil packs. Up until now we have had to limit the boost and revs because of spark blowout. The single coil didn't have enough time to regenerate and produce a decent enough spark for the boost after about 6000rpm, so it used to start missing. Now with some meaty coils on each cylinder we should be able to let it rev a bit further, maybe with a tad more boost .

The main reason for the map tweeking is the result of some inlet manifold balancing. On a jerry-rigged flowbench we found that No.3 was getting less than half the air of the others and No.s 1 and 5 getting more than the other 3. The problem is more obvious at lower air speeds (i.e. low boost) but still evident at higher air speeds (high boost).
So after some very time consuming engineering and re-measuring on the manifold they are now almost even.
As a consequence, No.3 is no longer running rich, so the fueling measured at the lambda in the downpipe (as an average of all 5) shows the engine is now running leaner.
It's not been quite as easy as shifting the fueling map up a bit, but the lambda is fed into the ECU and can be datalogged along with revs, throttle position and fueling map position. So with a bit of driving around, reviewing the datalog graph and adjusting the appropriate fuel map site where it is running lean, it seems to be getting there.

I'm only trying to get it drivable and safe (from detonation) to use next weekend and then I think it'll need a session on the rollers. Up until now we've been up to Emerald themselves for mapping, to see Dave Walker.

With the nice strong spark and all 5 cylinders theoretically getting the right air/fuel ratio and working properly it feels a lot, lot stronger, especially low down pick up .

With risk of hijacking a thread you've clearly attempted to avoid hijacking... (If you get my drift).... John (at JMR,) was adamant 'NOT' to modify the AAN inlet manifold, as Audi had spent hundreds of hours working out the manifold air flow balance to each cylinder and 'cutting' the manifold would compromise this flow and any water cooling the AAN inlet manifold jacket provides around the throttle bodies. Johns' approach is pretty much 'Audi knew best' for the engine air passage/delivery (the AAN standard inlet manifold delivers the air mid-manifold)... Which is easy for a 20vT convertee, but groundbreaking for a 10vT.

The brave take the more challenging path...

[Tim C]

Originally Posted by Isimmo

With risk of hijacking a thread you've clearly attempted to avoid hijacking... (If you get my drift).... John (at JMR,) was adamant 'NOT' to modify the AAN inlet manifold, as Audi had spent hundreds of hours working out the manifold air flow balance to each cylinder and 'cutting' the manifold would compromise this flow and any water cooling the AAN inlet manifold jacket provides around the throttle bodies. Johns' approach is pretty much 'Audi knew best' for the engine air passage/delivery (the AAN standard inlet manifold delivers the air mid-manifold)... Which is easy for a 20vT convertee, but groundbreaking for a 10vT.

The brave take the more challenging path...

It's like being a triple agent.

To a large extent I'd agree with that. We've always said that Audi came up with all the bright ideas and did an awful lot of development work to optimise performance, particularly for motorsport. So a lot of what we have done has not been purely for the "recreation" aspect, but also there's no point re-inventing the wheel. If we can improve on anything with a bit of modern technology, all the better.

Audi also benefited from a huge budget which allowed them to manufacture bespoke parts such as inlet manifolds for their 10V engine (you remember those Ian ). In order for us to recreate (because it worked well) the layout of turbo, intercooler across the front, induction pipe back across the engine to the rear of the inlet manifold, we used an inlet manifold from a non intercooled 100 IIRC. It had the throttle body at the back but it was to the left, away from the engine. We chopped that off and grafted a new one on facing the other way.



In doing so, the air comes in from the opposite direction for which the inlet runners were designed, hence the further modifications.

So in employing the "Audi knew best" policy and copying the layout but not having the budget for a bespoke a manifold we've had to work with what's readily available .

Could have just dropped a 20V lump in it I suppose .

[Tim C]

After sorting the fueling at the lower range, last night we started to take the revs further up and start making some boost.
It seems the spring in the new wastegate was a bit strong, it hit the 2.2 bar overboost limit at about 4500 rpm! 'Kin 'ell, did it pull though . Not sure how long it would hold together though .

A weaker spring in there tonight allowed the N75 valve to take control of the boost, holding a more managable 1.5 bar. Might edge it up a bit more tomorrow .

[Tim C]

We kicked the year off with another sortie of the Group R quattros at Rallye Sunseeker.
Now our hill climb and sprint season starts in earnest next Saturday (26th), where we left off last year, at Castle Combe.

Last October's sprint was 1 full lap, a starting from the grid, a flying finish across the line and back in the normal pit exit.
This first event of the year is a lap and three quarters. Starting from the pit exit, doing a full lap and then carrying on round for a second lap to the finish line just after the second chicane and exit via the pit entry lane.

Can't wait to get going again .