It lives

[RGV]

Hey Paul, im more than happy with the way the bike performed at the Lake. Im just having trouble convincing myself that 56 RWHP got me to 140 MPH. Perhaps I dont need to work on the Aero like I was going to.

Yep a bit of over rev would be good. This motor was just to test the new piston rod combo so I can build a Methanol burning one but I might keep going on Gas now.

Im out of work at the moment so didnt have the $$ to play round with tuning on the Dyno. I might be able to get some more HP and over rev by tuning the ignition and I know I can go leaner.

After looking at the Dyno readout I can pull a heap of ignition out of the top end to get some more heat into the chambers and create some over rev. As this motor didnt rev like I thought it might I had the ignition set to peak around 1000 RPM more.

Just did a comp test and the left cylinder is down 10 PSI. Ill rip it to pieces and see what I can find. Only 11 months to go.

[AuotonomousRX]

What is the cc of that Head you're running Dave?

Pete

[RGV]

10.5 cc excluding plug hole.

Dave

[AuotonomousRX]

Dave

As far as the RPM side of things, when I ran the 9.5cc Inserts, my Engine would not Rev past 10500 rpm.

When I fitted the 11.9 cc Inserts It would Rev to 11500 rpm with the same Tune and Ignition Map.

I wonder if that is going on here maybe?

Pete

[RGV]

Hey Pete

I kept this quote from a post on the RGV forum from Vince.

"when inserts have high compression ratio and large squish band, the mid-range is better, and when the compression is low and squish band small the high-range is better."

These are still my original Lozza Heads. They were only ever meant to be a general purpose/track head.

So when I get my O ring groove re-profiled I might get an extra cc taken out. Who wants mid-range LOL.

Dave

[ChrisACT]

If you can increase your crankcase volume, you'll get a higher redline. It lowers the pumping losses (lowers crankcase compression).

If your engine is a reed valve thing then spacing your reed valves out from the intake has the same effect. It's not massive but it all helps.

An easy way to raise your redline is shorten your pipe but that will cost you in the bottom end.

[RGV]

Hi Chris. Ive got reed spacers installed but the RGV's have big c/case volume. More might be better but thats some thing I need to test on a dyno.

Ive also fitted longer rods and lifted the barrels, mainly to have stronger rods and pistons but this also increases c/case volume.





Im going to try ceramic coating on the chambers to raise the gas temp. I painted them with black ceramic VHT paint this time.

Ive got no bottom end to loose so thats another option. Im just starting to get my head round chamber design I think. From what ive read the belly would be the section to shorten? Thanx

"Belly - Located between the divergent and convergent cones, it's length determines the relative timing of the negative and positive waves. The shorter the belly the shorter the distance positive waves travel and the narrower the RPM range. This is good for operating at HIGH RPM only. The longer the belly the broader the RPM range. The diameter of the belly has little or no effect."

Ive been reading up on ignition advance and am pretty sure I cam use that to get some more RPM.

Im open to suggestions.

Dave

[Stayt`ie]

Dave, my inital comment about getting the power not to drop away so quickly, was not so much increasing the rpm range, but, flattening the top horspower curve out ,, instead of it rising to 10500 then falling apruptly away, try and have it up near peak earlier at say 9800 then a slow curve over to lets say 11000, round the top of the hill so to speak,, back in the day with my Mach111 in drag racing we went searching for torque (this was no mean feat with a mach111 ), i seem to recall that we fattened (and legenthened ) the chamber in the middle and made the header pipes longer, also widened the transfers and kept the exhaust ports top low (standard),, we were kids back then and couldnt afford dyno tuning, however "seat of the pants", and improved timing slips told me something worked somewhere,,
by flattening the curve you will be helping the driving forces at the wheel at and near top speed, ,,

[AuotonomousRX]

Dave and I are both looking at ways to get the most out of these Engines for Land Speed Duty.. it's a learning Curve....

Ron to get an RGV to make more Power you have to get it to Peak at 11500 +, it's just the nature of the Beast, with a 56 x 50.6 Bore and Stroke.

Dave's Curve is a typical RGV with Tyga Pipes shape.

And yes, Pipe Design is Critical and it's the central point where and how much Power can be made.

As Dave said the known way to get less drop off, Over Rev, is through Retarding the Ignition Timing, this "extends the On Pipe range" by maintaining Exhaust Temps a little longer.

We are lucky these days with the Zeeltronic Adjustable Ignition, it allows us to get the Curve right...eventually...

It is getting the rpm reading of your Peak Power and then you can get the Timing to line up .... I think both of us are just starting to get the Basic Data to go forward.

The next 12 months in RGV Land will be very interesting I'd say

Pete

[BONES]

If any of you guys are in Sydney you are welcome to measure up some TZ cylinders.
The setup will be similar with the crankcase reed.
Alex is making noises about putting my A model TZ into his chassis---- 90 hp should liven it up

Bones

[AuotonomousRX]

What Year is the TZ A model Bones?

Pete

[dplecko]

[BONES]

The A is 1990--3tc reverse cylinder
also have-- 3yl
& -- 4dp
Bones

[Stayt`ie]

ya know ya want it Pete,

[AuotonomousRX]

Ron, I'll get a TZ, when you get a Busa

I would go the late model Honda RS250 engine for A 250 Classes but the Superkart Boys have stuffed that idea +++ $$$$

But I'd say I got at least one more Year in APS, got to be third time Lucky.

There is still M/G and PP for my RGV ..... then again SC is always an option

Pete