Stirring up the class 2/3 debate

[Peter Carmichael]

I just found these words on the web from Dave Andrews, dating back to 2001:

Here is a real example from a big rolling road day at Walkers workshop on Sunday 15th, two

engines, one an 8 Valve 'Kent' Crossflow, 1780cc, fully worked big valve head, 296 degree cam

40 Webers and 4->1 exhaust, the other a 16V Rover K series 1788cc, standard head, standard

plenum, 268 degree cams, 4-2-1 exhaust.

Both engines made around 146BHP (xflow 145, K series 147)

The following figures are torque in ft/lbs

 

RPM 8v 16v

1500 45 56

2000 68 91

2500 101 130

3000 112 133

3500 112 129

4000 111 132

4500 126 140

5000 129 136

5500 130 134

6000 126 126

6500 112 118

7000 99 108

 

Speaks for itself... at 1500 RPM the 16v has 24% more torque, at 2500 the 16v has 29%

more torque, at 4000 18% more. These are real life engines, no theory here, in order to match

the 16 valves output the 8 valve has to use a lot more cam and a big valve head fully reworked.

This has worsened its low down torque. The output from the 8 valve is considered very good for

a road engine too.

 

So this shows the clear advantage a 16 valver has over the crossflows for any given peak power figure.

 

Edited by - Peter Carmichael on 30 Sep 2004 16:16:52

[barry.h]

Good comparison.

 

To add fuel to the flames my X-flow produced 165bhp but torque still maxed at only 130 lbs/ft.

 

Also k-series is lighter and better positioned in the car.

 

Barry

[robmar]

without going into too technical a debate (which I would loose due to lack of knowledge)

 

how can you explain the following, times across the line at curbuuger in August

 

best xflow - DaveMc 1700 xflow - 97 mph

best 1800 K - Paul Dickens - 87 mph

best 1600 K - Adrian Williams - 86 mph

 

please don't get too technical

 

rob

[robmar]

I guess what i meant to add was that witht he rules as they stand

 

it is possible to get far more out of a xlfow (irrespective of the figures you give) than a K

 

none of the 1600 runners in class 3 seem keen or likely to be modifying there cars internals so I would not expect any of them to have much over the 147 you mention....

 

rob

 

PS I am happy for the regs to stay as they are

[Graham Perry]

My crossflow max's out a bit more than Barry's did, but at 3500 produces only 65ft/lbs ☹️

 

So could a crossflow be said to benefit from a 6 speed more than a K in that case ?

 

Edited by - Graham Perry on 30 Sep 2004 15:09:24

[Peter Carmichael]

Rob,

 

I won't get technical, because the point you make is right. Dave's speed across the line indicates a surfeit of power and can't be anything else. FWIW, with a Fen-Emerald 157bhp I was getting ~91mph across the line. (With Brixton Emerald 253bhp I used to get 106mph).

 

I am sympathetic to your cause. Starting from a principle that compliance with tech regs need to be easily verifiable, I have always reckoned the only way to go was:

- top crossflow spec - anything goes on twin carbs.

- 1.8 litre K spec - anything goes internally on a standard head casting, but still on a standard production plenum - up to 52mm single TB allowed - Emerald or other mappable ECU allowed.

- 1.6 litre K spec - anything goes internally on a standard head casting, but still on a standard production plenum - up to 52mm single TB allowed - Emerald or other mappable ECU allowed.

 

Worth remembering that two notable top runners in class 5 have been running 1.6 Ks against all-comers, so the difference 1.6 to 1.8 appears less of an issue than the state of tune.

[barry.h]

I suppose that the only other thing apart from differences in transmission train losses which might affect speed across the line is the presence or absence of a screen. But given the 150+bhp involved any measurable effect will presumably be at higher speeds?

 

The concept of a surfeit of power is possibly alien to us but 97mph certainly suggests significant bhp. My 165bhp was only good for 94mph - albeit with a screen.

 

Barry

[david nelson]

Intresting post.

 

I said I was happy with the regs as they are, but also stated that if there was an x-flow or twin lotus that had significantly more power/torque that this car should be put into class 4 or 5. If this does not happen then all the K series will be fighting for is 2nd place.

 

Time will tell what happens, but may be we need more data like Peter's posted to make an educated/sensible disition on where class 2 and 3 go for 2006.

 

 

David

[robmar]

Peter - we only have the current 1.8 no mods rule to annoy the heck out of the 1.8 boys especially Mr Nelson 😬 rather than any real technical reason

 

Barry - Dave has one quick car (and he is not a bad driver to boot), I wasn't at Aintree but I think he was 125 plus over the line

 

rob

[david nelson]

Rob 😬 😬 😬

[robmar]

[annoy the 1.8 boys mode]

 

the problem with what you say is that there will always be some people with more power than others.

 

And even if the mythical 190 bhp xflows or twinks do exist, they would not have much chance in class 4 or 5. So unless you create a new class then you will not please everyone. i think 6 classes is about right for our championship and I don't see why we should change for now.

 

I think Adrian and Paul Dickens showed that it is possible to get close to DaveMc and Tony Thorp. You and me will just have to try harder next year 😬

 

Plus also remember that cars at that state of tune sacrifice reliability int he quest for power, ask DaveMc so sort of balances it up.

 

[/annoy the 1.8 boys mode] 😬

 

rob

[Adrian Williams]

Guys

 

Speeds across the line @ Curburger:

Dave Mc 96

Paul Dickens 88

Me 85

 

@ Aintree

Dave Mc 121

Me 107

Mark Durrant in 1800K with 1a's 114

 

Adrian

[david nelson]

It go back to the origanal post's point I think or was it Peter's idea of class regs.

 

I am happy to sit and wait till 2005 to see what happens. I think Peter's idea of what is allowed is ok, but I thought one reason for keeping thing as close to standard, was to encourage new compediters.

 

We know the 1.6 and 1.8 are close its down to drivers as you put it Rob, Adrian and Paul are close, and we are a bit further back ☹️.

 

 

David

[robmar]

well as we are all stirring

 

I reckon we should send the 1.8's back to where they belong after this years 'experiment' and have a blanket 1600 cc max rule in class 2&3, what do you reckon Adrian 😬

 

BB - i bet you are glad you are out of this now 😬

 

rob

[Adrian Williams]

Sounds like a splendid idea to me Rob 😬 😬

 

Talking of Graham he was 105 @ Aintree

 

 

 

Adrian

[david nelson]

The only reason to ban Paul and me from class 3 is becouse you are in fear of what might happen in 2005.

 

long live 1.8k's

 

 

ps anyone reading this with a 1.8K and would like to join class 3 next year is more than welcome, is just the boys with the small engines are throwing the toys out of their prams (cars)

 

 

David

[robmar]

[Graham Perry]

We seem to have various trap speeds quoted. Anyone got those for classes 2/3 for MIRA as iirc there were some closer speed differentials there

[Mark Durrant]

Graham

 

The only thing to take into account at MIRA is that the speed trap is immediately before the braking zone at the control tower and therefore it is not as conclusive as some will be lifting before braking for the corner.

 

Mark D

Su77on Se7ens

Considering my options for 2005

[Graham Perry]

Not me, I have still got the skidmarks 😬

[Steve Robinson]

IIRC my speed across the line at Curborough was sub 90, so it really is only the very highly tuned X-flows that are pulling any significant advantage. Mine is thought to be in the region of 145 BHP, and I bet I lose more through having no LSD and drum brakes at the back than any slight power advantage may gain me.

 

I still favour leaving everything as is which gives me freedom to throw vast pots of cash at my engine so I can nick some prizes next year 😬