Saulius' turbo 1100M

[Captain Chaos]

Check valve has no influence since it's lying in the bin.

Now Saulius has changed the plenum a bit, the air is coming in from the bottom and not from the side. Together with the air pressure pipes/tyre valves these are the only mods this winter.

Main jets were 132,5, everything was fine before, A/F around 11,5 - 12. Now with the modified plenum and vacuum pipes it is running really rich, with main jets 112 (Dynojet, Mikuni equivalent is 105) it is still too rich, constant throttle around 11, under load around 9,5 and it starts misfiring.

Could the modifications with the tyre valves cause this richness? Or is there anything else we overlooked? He drained the fuel and filled up some fresh fuel, still the same.

 

[Jaydee]

On 4/27/2016 at 7:24 PM, Blubber said:

But... Won't the check valve in it, cause a faulty reading 

I thought this was sarcasm as the internal valve would obviously have to be omitted to work. Still have to get a hang of this sarcasm lark. 

[bruteforce]

I'm still not sure what the "tyre valves" connections are used for? On my bike I only have two connections on the "carb balancing" points: One goes to the fuel reg and the other to the BOV. How could these be too small as they only give boost/ vaccuum reference?

 

Only thing I know is that a change in plenum shape/ size ALWAYS affects main jets. And if you have rich mixture now, that would indicate that the dynamic boost is working way better.

[Captain Chaos]

I'm not too sure about the tyre valve things either. Saulius explained it to me, and it seemed plausible. Basically the vacuum take-offs are too small, when he opens the throttle the fuel pressure comes in a little bit later than the boost.

Anyway I suggested him to change it back to how it was and go for a ride, he did today, I met him by accident on the way home from work and he said it's still way too rich. So you suggest that the change in plenum shape makes a 30% smaller main jet needed? It was 132,5 and now with 105 it's still too rich. Stock jet size is 125 and according to those who know usually slightly smaller is needed with boost.

[bruteforce]

15 hours ago, Captain Chaos said:

So you suggest that the change in plenum shape makes a 30% smaller main jet needed? It was 132,5 and now with 105 it's still too rich. Stock jet size is 125 and according to those who know usually slightly smaller is needed with boost.

All I know is from my own experience, I'm no scientist and can't really explain why. On my old aircooled TurboGS the plenum was larger than the one I have on now. That needed near-standard mains. On my GS550 based new TurboGS I have a smaller plenum and now I need 134DJ mains to cope (instead of 112mikuni). apparently the "dynamic boost" is relying on a certain volume of plenum. I hear some people say that they need to restrict their pitots size because it runs way rich. Never had that myself!

Same story on buddy Eggberts' old wheelie bike that had an oilcooled turbo GSXR motor: He changed things on the plenum and immedeatly needed mains changes.

Edited May 3, 2016 by bruteforce

[bruteforce]

15 hours ago, Captain Chaos said:

I'm not too sure about the tyre valve things either. Saulius explained it to me, and it seemed plausible. Basically the vacuum take-offs are too small, when he opens the throttle the fuel pressure comes in a little bit later than the boost.

Okay, I take it that he's seen that on some pressure gauges. But the lagging of fuel pressure doesn't have any effect because the floatbowls will maintain their fuellevels it that little lagging time. If the boost is measured on the plenum and fuel reg reference is off the vaccuum ports (like it should be) there will always be lagging. 

Edited May 3, 2016 by bruteforce

[Captain Chaos]

Ok, thanks for the answers. Now we know in which direction we should look / work.

 

[Captain Chaos]

Saulius called me this afternoon, he said he connected something to the plenum and not on the Pitot tube, and everything is as expected now (running very lean on #105 main jets).

Sorry I'm not more specific but I had Saulius on the phone, while answering a customer's questions in the shop, and yet another phone call coming in.

[Captain Chaos]

He visited me today at work while "test-riding". Connected the carbs on the plenum, and everything else boost-related on the tyre valve things in the intake rubbers, and it rides perfectly now, instant boost when opening the throttle and the fuel pressure rises emmediately with the boost. Main jets are slightly too small (127,5 now) but he will change them.

On 2016-05-03 at 10:06 AM, bruteforce said:

 If the boost is measured on the plenum and fuel reg reference is off the vaccuum ports (like it should be)

if it should be like this then what is the use of the pitot tube? On Saulius' bike it is now half way between the compressor and the plenum. Would it be better closer to the carbs, for more accurate boost signal?

[Gixer1460]

For me, I wouldn't have used the 'vacuum' ports for fuel reg as this will try to lower fuel pressure when throttles are closed - ok with EFI and is the norm but not necessary with carbs. They just need a static FP that rises dynamically with boost that is sourced from the pitot tube.

[bruteforce]

1 hour ago, Gixer1460 said:

For me, I wouldn't have used the 'vacuum' ports for fuel reg as this will try to lower fuel pressure when throttles are closed - ok with EFI and is the norm but not necessary with carbs. They just need a static FP that rises dynamically with boost that is sourced from the pitot tube.

Was engineered like this on the good old Yammi XJ650T and as I'm stil using its fuel pump and regulator this is how I configured it on the TurboGS

[bruteforce]

@Captain Chaos Pitot tubes go to the carbs, boostmeter is usually fitted to the plenum

[Captain Chaos]

Ah ok.

Anyway we should meet in real life one day this summer and talk boost and stuff.

[bruteforce]

On 5-5-2016 at 7:11 AM, Captain Chaos said:

Ah ok.

Anyway we should meet in real life one day this summer and talk boost and stuff.

I'll be at the Cadwell OSS meet and at the Wheelie Record weekend at Elvington

[Captain Chaos]

you'll not be at the Dutch OSS thing at Rene's place in August?

[Captain Chaos]

Saulius got it running correctly now.

Today we went for a little ride, around 300km in total (glorious hot and sunny weather here) and after swapping bikes I can confirm:

 

[Captain Chaos]

About my B12-engined EFE Saulius said: "it's like a motorised sofa".

[Arttu]

Reminds me a case when we did similar test ride with a friend. He had a big bore Kat, about 140hp, I had the first turbo revision of my 1100E, maybe 180hp that time. First we swapped bikes, agreed to ride about 20km and then swap back. Once we got in the turning point he was smiling from ear to ear and asked if he could ride it back too

[bruteforce]

On 7-5-2016 at 7:27 PM, Captain Chaos said:

you'll not be at the Dutch OSS thing at Rene's place in August?

Sure, if I'm not away on holiday. Rene lives very close to me.

Edited May 9, 2016 by bruteforce

[bruteforce]

I'm glad to hear that it runs great! Turboz are addictive and when someone wants to swap bikes I simply say NO, because...  and then the excuse-book opens...

Edited May 9, 2016 by bruteforce

[Saulius]

:-)

[Captain Chaos]

Today again we went for a little ride. Saulius upped the boost slightly, and now in 4th gear it easily lifts the front wheel, in fifth only just. Saulius said that like this it's fast enough.

Dyno run planned for later this week, dragrace next saturday.

And of course after trying it, all I can say is:
 

[Captain Chaos]

Saulius had the thing dyno'ed today. 180 hp at the wheel, not too bad.

 

 

[Captain Chaos]

in preparation for the dragrace this weekend, Saulius decided an extended swingarm would be a good idea. So he bought a B12 swinger at the breakers' (most likely from the same B12 I got my engine from), cut it in pieces, and added some bits of profile. The B12 swingarm is 5cm shorter than the 1100M one, he added 15cm, so now it's 10cm longer than stock.

 

[Captain Chaos]

The result looks amazing. And just like everything else on this bike, it has been done by himself and a mate who can weld pretty well. Nothing bought in, all home made.

No test ride yet, this afternoon (for the first time in 4 weeks) we had some rain. But it should be a massive improvement.