ESE's works engine tuner

[F5 Dave]

Hmm, how far out do you think usable charge flows?

Thanks for response.

[husaberg]

Hmm, ok lets talk pipe temperature insulation while the topic is up. We used to see lagged pipes, then that went out of fashion, possibly Ti pipe insulated better was postulated, but largely there was talk of the charge being returned to cylinder cooler was better.

Think it could have started with the snowmobiles as they supercool so lagging really helped. As an aside we've seen the lagging to avoid heating the cases.

Clearly there was the overall change in timing of wave. I've lagged & HPC coated my 50 pipe (awaaay back in the day) & all it achieved was rust, maybe 100rpm move & no power change. I HPC coated my 500 pipes (250x2) for convenience (its a roadbike), thinking it would not do squat but keep it looking nice & unrusty but heck did it whap the peak revs up, maybe 1000rpm. Stripped them & went for boring old paint.

"Is there still a place for them?" I should think so; look at the Aprilia RSA125. There the cover does two things: shield the pipe from a cold air stream, but more importantly, as you can tell by the shield covering only the top half of the pipe: shield the crankcase from radiated pipe heat.
How much difference? We can only guess (which I avoid as much as possible) because nobody ever took the trouble of measuring the difference on a real track (were measuring the power would not be simple anyhow). The crankcase-shielding will give more power everywhere and the pipe-heat conservation will give more overrun which is extremely import for lap times.
Attachment 249819

The insulated pipes also (for those that missed it) the first time arround i missed it before Frits mentioned the cases............

[Grumph]

Quick question for Frits or Wob - material for spacers on the piston pin for overhead rod guidance ? What works ?

Background - I was shown today two Suzuki TR500Mk3 cranks which use this method of rod location. The guy rebuilding them has had bad experiences with the spacers breaking up and is converting them to big end thrust washers.

Given that this era of racebike is now used in no more than 15 minute bursts I doubt if it'll cause a problem but I'm curious....

[wobbly]

7075 is the material of choice for the KT100 Yamaha that runs the upper end washers, but they are still no where near reliable as " proper " silver plated big end washers.

[RAW]

7075 is the material of choice for the KT100 Yamaha that runs the upper end washers, but they are still no where near reliable as " proper " silver plated big end washers.

7075 Aluminium has the highest ultimate tensile strength of all of the commercially available grades, However at elevated temperatures it becomes quite soft compared to most of the other commercially available grades, in short there's more to it than just the advertised room temperature data in the shiny brochure.

[RomeuPT]

I always start at the header and work along, these sections are easy to hammer and linish with a 25mm flap wheel in a die grinder.
The rear cone is thus the last and I use a length of 19mm Hi Tensile bar with the end radiused, clamped in the vise,to hammer the last joint smooth.
Make very sure the ALL grinding grit is wiped out, when the engine first fires all the shit will end up on the piston face and cause havoc.
I use argon purge inside when making Ti chambers, but its not really the weld thats the issue with mild, its the slightly uneven joint overlaps.
A hammered header radius looks and performs better than the as welded sections do.
Tig is way faster and WAY cheaper than a gas welded pipe, but I still think gas welding looks better if done right.

Thanks again, this is such a great topic, I cannot say otherwise...

Yes the exhaust's are tig welded, right I will hammer the curve a bit and try some grinding in overlap joints, mostly on the strong exhaust's...

I usualy make each cone with 6 or 7 of cut angle, so a joint will have a total of 12 or 14º angle. I think it was in the 2 stroke tuners handbook that each cone should not have more than 7,5 or so if I remenber...

I am using 1mm mild steel, cheap, resistant, relativelt easy to work, I think is the best compromise.

Possibly will try some stainless steel soon....

Regards

[wobbly]

You will find that 0.8mm cold rolled will make more power than 1mm every time.
If you want to get really tricky, make the header and last 1/2 of the rear cone in 0.6mm.

The upper end washers take a bashing over a much smaller bearing area than big end washers do, if the crank is not dead straight they fail from cracking - the lower strength
at elevated temps isnt an issue.

[F5 Dave]

You will find that 0.8mm cold rolled will make more power than 1mm every time.
If you want to get really tricky, make the header and last 1/2 of the rear cone in 0.6mm.
. . .

So we are talking cooling again? As the di get smaller but why at the end?

[RomeuPT]

You will find that 0.8mm cold rolled will make more power than 1mm every time.
If you want to get really tricky, make the header and last 1/2 of the rear cone in 0.6mm.

The upper end washers take a bashing over a much smaller bearing area than big end washers do, if the crank is not dead straight they fail from cracking - the lower strength
at elevated temps isnt an issue.

Well , why it makes more power in a theory explanation?
What is the difference between cold rolled and a spread sheet?

Actually the ideia is good for the final cone, or baffle, because is the hardest piece to work with, using of course just one cone for it..

Sometimes the cones go a little oval, not perfectly round, would that be utmost important to performance?

Thanks

[RomeuPT]

So we are talking cooling again? As the di get smaller but why at the end?

If you want to keep temperature...
I am thinking if the steel get's in play with the ressonance effect, and 1mm would "eat" some of the "energy"?

[wobbly]

1mm takes a long time to heat up, and in reverse takes a long time to cool down on trailing throttle into a turn.
0.8mm is the best compromise between weld strength and power.
0.6mm isnt easy to weld with good strength, but it does work "better".
Using thinner sheet at the header, and the end of the rear cone - the hottest areas in a pipe means they will heat up faster, getting the engine onto the pipe faster
but also they will cool quicker, equalising to the lower overall temp quicker on the overun.

I gave TeeZee a RS125 A kit pipe I made a while ago in 1mm to the Honda dimensions - it was useless on the dyno, but maybe he can take a pic of the hammered welds at the header to
show how nice it can be done.

[RomeuPT]

1mm takes a long time to heat up, and in reverse takes a long time to cool down on trailing throttle into a turn.
0.8mm is the best compromise between weld strength and power.
0.6mm isnt easy to weld with good strength, but it does work "better".
Using thinner sheet at the header, and the end of the rear cone - the hottest areas in a pipe means they will heat up faster, getting the engine onto the pipe faster
but also they will cool quicker, equalising to the lower overall temp quicker on the overun.

I gave TeeZee a RS125 A kit pipe I made a while ago in 1mm to the Honda dimensions - it was useless on the dyno, but maybe he can take a pic of the hammered welds at the header to
show how nice it can be done.

Thanks, and after the exhaust is covered with carbon inside, it still makes important difference?

Most 2t people here in Portugal, mostly DT and DTR 125 do drag races with friends at friday night... The exhaust's are not for track use, but may the same rule apply...

Regards

[F5 Dave]

whoa. erm thanks I think. might be time to go for a walk & think about that,

[wobbly]

Drag racing its more important - starting with a relatively cold surface the thinner pipe will heat up quicker.
I could also add that after several huge single malts I just " maybe " believed the VIP storyteller, that thinner pipe walls pulse or resonate more - but who knows, all I care is that they are faster.

[Buckets4Me]

Drag racing its more important - starting with a relatively cold surface the thinner pipe will heat up quicker.
I could also add that after several huge single malts I just " maybe " believed the VIP storyteller, that thinner pipe walls pulse or resonate more - but who knows, all I care is that they are faster.

I can tell you from experiance that the thicker the pipe the longer it lasts (very usefull in the 2 hour on a wet day)

thinner walled chambers don't tend to last well after being droped run over and chrashed into