Scary day tomorrow

[Darkspeed]

Out of interest - assuming an ambient of 15C and a RH of 50% - what pressure drop are you expecting along a 500mm long duct and what sort of entry is being used?

Can I just clarify, I don't beleive ram air has a measureable effect, but I think you're missing the point...
Pub bragging figures have no basis in science... and bragging is what Yamaha are doing when they claim there figures.

That said, there's more than enough air going down an inlet at speed to supply an engine without is having to suck. Stick an unrestricted 4" pipe in a 100mph air flow and over 200,000 lts of air will pass through it in 1min. Think thats more than enough to supply 7000lts into the engine.

[adithorp]

Presure drop... erm, honest answer?... Not got a Scooby Doo.

Inlet is via two 75mm flexi tubes in front of the rad'. Unfortunatly they had to be ovalised to fit the gap between rad' and bonnet, so now they won't take flarred bell-ends.

I got chance to do a bit of post RR checking today.Got a tiny oil weep butnot enough to worry about and a slight leak from the waterpump. This was worse when the engine first ran (result of standing for 2 years and the pump gland getting dry I suspect) but it's just damp now (no drip).

I also got around to making a prop catcher for the rear (front one was fitted last year) and refitted the floor. Allready now for Blyton track on Sunday, when I'll find out what it's realy like.

[matt_gsxr]

Good to hear that you finally got that engine installed, and its a good one.

On the issue of Ram Air I agree with what has been said already. Its there but you have to look very carefully.

Here are some data that I collected with megasquirt when I had 1m long 100mm diameter hose pointing out the front of my grill (pre-turbo install).

This snippet is through the gears 2, 3, 4. The MAP is of interest, as with the increasing speed of the higher gears the MAP rises slightly (pale blue line scaled between 90 and 100) although all other characteristics of the engine remain the same. The increase in pressure is of the order of 1% (94kPa to 95kPa).


The turbo seems to add a bit more than ram air!

[adithorp]

Real world testing at Blyton today and the result is.... it's fecking great.

Pulls like a train. Before i could light the rears up if I really wanted/tried to, but now it'll spin them up anytime I like. Gained speed as well; Before on the back straight I could get to 100mph but only if I got the bend before absolutely spot on and pushed the braking point into the chicane Now it hits 105 every lap without pushing the limits too hard. Only thing going quicker was Danny Keenan in his race spec BUSA powered MK on slicks and to be fair he's a better driver than I am to boot.

Only down side was the number of red flags and the last session of the day it overheated. Fingers crossed it's just because I was pushing it hard for a long time. I think a new rad would cure that as the current ones fins are a bit the worse for wear.

[adithorp]

Started it up last night and it missed and ran on 3 cyls, #4 was wet (appeared to be fuel) so dried and warmed the plug, put it back and it started and ran fine,then started missing/OK/missing/OK. Shut it down, pulled the plugs and #4 was the culprit. Went home to sulk

Got here this morning and #4 cyl has a nice pubble of waterin it.

Still better it happens here than in France/Spain. Can I make Stoneleigh? Do I fix this or drop the old motor back in?

[jeffw]

Sorry to hear about the head gasket. Do you not have a water temp guage on the dash and a fan? Seems a little odd that it would overheat like that.

[adithorp]

Yeah and I'd had a glance going down the straight a lap earlier. Read 95c but oil temp was creeping towards 120c so was about to come back in. Suspect the gasket went and compresion gases blew the rad cap. At full chat the compresion gasses would overheat it very quick.

I'd thought I heard an odd exhaust note as I cme back in the previous time but had my helmet on so it was hard to tell. Stopped and took it off before having a listen and it sounded right so dismissed it as coming from another car in the paddock.The water level was OK at the time but there was a slight drip from the cap. I suspect the gasket was going on #4 then and what I heard was a slight misfire which disapeared by the time I'd taken my helmet off, opened the bonnet and restarted.

Feel free to take the piss Jeff... I did it to you.

[jeffw]

Nope....I don't enjoy other peoples mechanical issues.....

So it actual sounds like the oil temp is the major issue and the water is a side effect. I guess you might need a bigger oil cooler.

[adithorp]

I'm just running the standard oil to water cooler. Looking at the guage it was actually 110c. I think a new rad will be enough to keep the temps down and cope. I'd like to avoid the complication of fitting an oil cooler if I can and the race bikes don't use one I beleive.

Speaking to a guy who builds race engines (and works alongside the guy I got it from) it seems I may have fallen victim to a common tuned R1 problem. #4 cylinder runs up to 20% hotter than the rest due to having no water jacket around 1/4 of the cylinder (where the cam chain gallery is). As a result detonation can easily kill it.

If your too keen with the mixture/timing at full throttle or don't pay enough attention to low/mid range then that can be an issue. We spent ages getting the low/mid range sorted and were pretty conservative at the top end last week. So I suspect it had been mortally wounded before I got it.

Either way it's got to come out and given the spec I think I'll let the experts re-build it; I wouldn't like to get it wrong. Just hope he can fit it in amongst his pre-TT rush. Then double check on the RR to make sure it wasn't our fault. Might be tin-top for Stonelleigh... is it worth the effort to drop the old one in temporarily?

[dopdog]

Yeah for the sake of an afternoon, just do it.