Special getting closer...

domtoni · Post by **domtoni** » Mon Jun 27, 2011 2:56 pm

Just a quick thought, and I am most likely a bit off base, but when the Cosworth Escort was under development, I was at the Ford test ground and the UK development engineers took off the big superwide tyres and put on the Sierra Cosworth 6 inch wide wheels. The lap times around the test circuit increased considerably (don't remember just what the numbers were after 20 years).

Anyway, I am off to Italy a week wednesday and will be north of Bologna.

911hillclimber · Post by **911hillclimber** » Mon Jun 27, 2011 5:22 pm

Just got back from Lake Como!

There is quite a debate about the wheel width elsewhere in hillclimb circles, many say it is far tooooo wide, but the real issue is in a drag race start the car does not go like 440 bhp/ton is should be.

My 73T 911/3.2 is as fast on road tyres!

going to re-jet the carbs soon and see what happens. The engine spends most of it's time ticking over or 80+ % throttle opening so tune may not be too sensitive.

Enjoy Italy!

Graham:

Those pesky mites in this engine you describe i hope will be gone soon...
Hows that Radical repair doing if the back is OK?

gridgway · Post by **gridgway** » Mon Jun 27, 2011 6:58 pm

the Radical repair is going very well indeed tks. So well that by a miracle of economics, there is a new car in build to replace it! Bizaare but true.

The back is doing well, I've had the all-clear to restart the racing when the pain is diminished enough. That'll be at Donington in 7 weeks hopefully. It feels unlikely to be in 2.5 weeks as I am still sitting on a cushion with a hole in it!

Graham

domtoni · Post by **domtoni** » Tue Jun 28, 2011 9:03 am

Graham,

Just a thought. I was never a big drag race person, but in drag racing, you need a bit of wheel spin to get the car launched. If the tyres are too wide, you risk bogging the engine on start. But as you say 440 bhp / ton is alot and it should go like stink.

911hillclimber · Post by **911hillclimber** » Tue Jun 28, 2011 12:49 pm

This car has an LSD, 14" wide AVON hillclimb slicks softer than a draftsmans rubber, aluminium covered Sach clutch and it certainly wheelspins off the line.
It does not spin after that in any other gear though.

I leave the line at 5000 rpm and dump the clutch. Car covers the first 64 feet in 2.1 seconds, same as my road spec 911. My slick shod Impreza did 1.86.

Getting the new jets tomorrow.

domtoni · Post by **domtoni** » Tue Jun 28, 2011 2:34 pm

The Impreza certainly got the power down in a far better fashion. Just curious, how wide were those tyres? How much power did the car have?

Also, what's the torque curve like in the Lola? Sounds to me like the car is bogging after it launches.

Mike911scrs · Post by **Mike911scrs** » Wed Jun 29, 2011 10:22 am

HI Graham
do you know what cams are in the car and what the timing is set at??? Left and Right

regards mike

911hillclimber · Post by **911hillclimber** » Wed Jun 29, 2011 12:55 pm

Standard 1988 3.2 cams Mike and the timing was set in the middle of the tolerances in the Works Manual.

Bob Watsons set the cams in the end for me. Technician took great care to set them both.
On the rollers, Bob was happy with the actual timing etc and the rollers gave 269.4 bhp. no reason to doubt that, but it sure does not drive like 440 bhp/ton, hence my times.

At Prescott, the start is long and gently curved to the left (I think you have run Prescott?) and the speed trap says it all.

I go under the bridge measured at 67 mph, the Impreza did 78 and the 911 did 65mph.

Getting the jets today/tomorrow as spec'ed by PMO's Richard Parr as the starter jets. Will simply pop them in and run the engine.

Plugs are black and the engine clears it's throat off the start with a little black smoke.
Engine simply feels lazy in response to me.

I know I have 100% throttle movement etc so should be a rocket-ship.

Several Porsche driving compatitors say it just does not sound 'right'.

Two GT3's were as quick if not a second quicker than me. (on slicks).

I'll get to the bottom of this yet!

Gary71 · Post by **Gary71** » Wed Jun 29, 2011 1:01 pm

911hillclimber wrote:Standard 1988 3.2 cams Mike and the timing was set in the middle of the tolerances in the Works Manual.

Bob Watsons set the cams in the end for me. Technician took great care to set them both.
On the rollers, Bob was happy with the actual timing etc and the rollers gave 269.4 bhp. no reason to doubt that, but it sure does not drive like 440 bhp/ton, hence my times.

At Prescott, the start is long and gently curved to the left (I think you have run Prescott?) and the speed trap says it all.

I go under the bridge measured at 67 mph, the Impreza did 78 and the 911 did 65mph.

Getting the jets today/tomorrow as spec'ed by PMO's Richard Parr as the starter jets. Will simply pop them in and run the engine.

Plugs are black and the engine clears it's throat off the start with a little black smoke.
Engine simply feels lazy in response to me.

I know I have 100% throttle movement etc so should be a rocket-ship.

Several Porsche driving compatitors say it just does not sound 'right'.

Two GT3's were as quick if not a second quicker than me. (on slicks).

I'll get to the bottom of this yet!

When we are at Loton I mentioned it sounded like it was stumbling and sounded a bit reluctant coming out of the top bend.

Full power at max rpm may be ok, but I would concurr it sounded like it was overfueling on the way up there.

Any chance of just sticking a standard 3.2 injection system on it?

Bruce M · Post by **Bruce M** » Wed Jun 29, 2011 1:48 pm

I'm very reluctant to start throwing around fueling theories given that Bob has tuned the engine.

However, I get the feeling there is perhaps an issue with the acceleration enrichment. Perhaps if the carbs have had larger jets than PMO typically suggests, when you floor the throttle (you'll do that a lot on hillclimbs I guess), the pump jet may over fuel the engine making the response slow/mushy until the rich mixture has cleared (by which time you'll be heading for the brakes again or changing up?).
This rings a bell because some webers are tricky to set up because there is only one or two pump jet sizes. The real tuning is done by changing the size of the bleed valve which allows a proportion of the fuel to return to the float chamber, bypassing the pump jet. The give away is the sooty exhaust when you blip the throttle.

I know that the PMO enrichment is set up by adjusting the rod length but I also spotted the following in the PMO technical notes:

3. Reducing Injection Quantity

We have found that race engines often need varying levels of injection quantity. Coming out of a turn, too much injection quantity can actually cause bogging. PMO has different float bowl check valves to adjust the injection quantity up or down. Rob King at S-Car-Go has cut the injection quantity down to almost nothing with excellent results. The normally installed float bowl check valves have a .5 mm side hole for bleed back. The larger the bleed back hole the less injection quantity. The valves come in increments of .1 mm up to 1 mm. We have 1.5 mm valves for people who want to almost eliminate injection quantity but still start the engine. I'm reading "injection quantity" as acceleration enrichment here but I could be mistaken.

Also..... excess acceleration enrichment might not be that obvious on a WOT dyno run through the full rev range.

Again, I feel slightly uncomfortable suggesting that the carb setup is not spot on but since you have already decided to try a re-jet, I thought it was worth sharing.

Cheers.

Mike911scrs · Post by **Mike911scrs** » Wed Jun 29, 2011 1:49 pm

HI Gary
3.2 injection ? not with the cooling fan in that position, will need some PMO throttle bodes to run the EFI injection.

HI Graham
what fuel pressure are you running at the carbs, actual pressure not what a regulator set up is saying if it is one of the round dial a pressure things, as the PMO's are sensitive to fuel pressure and the float hight, are you running a fuel return to the tank.

regards mike

MikeB · Post by **MikeB** » Wed Jun 29, 2011 3:01 pm

Graham

Are you sure the ignition timing hasn't slipped, retarded itself?

I had some issues setting up the fuel pressure on my 2.2S with PMOs, over pressure by-passing the float valves, easily sorted with the PMO pressure adjuster. But it didn't adversely effect the performance, just made it a tad rich low down, but still pulled well. I think the carb settings would have to be way out to make the car under perform as much as you state.

I'd really have a look at the ignition settings and the voltage

Really hope you get this saga sorted, it's frustrating enough reading about it, never mind poor you trying to work through it.

911hillclimber · Post by **911hillclimber** » Wed Jun 29, 2011 6:25 pm

Thank you all very much for bothering with this divvel!

Bob did ease the accelleration pump stroke before he got stuck-in as it was a massive squirt.
The engine really does not feel 'get-up-and-go' at all, and sounds like that as Gary has heard first hand.

Bob and i thought the chokes too big @ 38mm but this is the size PMO supply for a stock 3.2 with 46mm PMO's. We thought 38's too big with a low signal in the air flow. They made set-up hard for Bob. We tried to get some 35's at the time which if too small could be bored to 36 on a lathe.

It feels slower to respond than my 3.2 in the 911 (stock injection).MB is right, the flat fan stops normal injection being fitted.

The fuel pressure is 3 psi Mike set by Bob and as spec'd by PMO. The fuel system is not return-to-tank.

I have to admit to being low about the car now. I too am very very tired of the difficulties I've been through.

Watching Peter's GT3 run a good second faster than me at Prescott in a car that cost less than this Lola turns me over.

My enthusiasm comes and goes.....

Still: this is unfinished business, it is also only a bloody 3.2 on carbs!! Why should it be so flippin ard?

A good thing is the box that MB did is getting nicer by the race and seems rock solid.

I now have the PMO spec jets, but Bob wants a call from me before I touch them!

I would be perfectly happy with 230 bhp if the engine had some sparkle.
Doesn't even sound like a flat 6.

MikeB · Post by **MikeB** » Wed Jun 29, 2011 6:38 pm

Graham

If it eases your mind from my experience Richard Parr knows his stuff, the set up he sent me for the 2.2 was absolutely spot on. The 3.2 is his bread and butter, so it should all be an easy swap

Good luck

(check the ignition...he repeats quietly

)

And the carb balance in case that too has got out of true

impmad2000 · Post by **impmad2000** » Wed Jun 29, 2011 7:39 pm

Not the same I know, but perhaps a useful comparison (?). I took all the accel enrichment out of my Megasquirt setup at Bob's, so that it didn't affect the overall tune, I haven't found the need to put it back !!
Good luck with it. At the minute you know its not right, just stay with it and hope the day it all hooks up is not too far in the future

Tim