Stephtell

I've also notice the changing the angle of the external wastgate has affected the way it operates so I can't wait to get on the dyno and see what I've done!

Yes, the smaller the diameter the higher the gasspeed, this much is true. However, gasspeed doesn't really tell the whole story: Due to the small diameter the engine can't breathe properly, it can't push out the exhaustgas fast enough which is affecting several things such as the burn inside the chamber, the heat of the engine and also spool up because now there's no restriction and more gasvolume to help spool up. Mind you, spool up isn't bad anyway. With this exhaust it idles easier, runs leaner at idle and it revs quicker so I don't think it'll be all that bad...a 1216 cc engine putting out 285 BHP on such a small exhaust is pretty good but imagine what a restirction the exhaust must be on this engine!

Thanks guys, usefull info here! Will check in to adapting the HSR 45 Zepp, my mate can CNC whatever I need so a new floatbowl with different fittings is no bother. Yes the yellow was fucking terrible...!!! I really should take some recent pictures and post them, will do so when the last bits are back from the painters! Meanwhile I've changed the complete exhaust!!! I kept to the design of GJG as far as the headers go only now I went from 28 mm internals to 30mm internals into a 60mm collector instead of 35 mm. Also I've complete changed the linkpipe to the turbo: from a weedy 30mm to 60mm and with an exact fit to the turbo rather than a 30mm round hole blowing into a suare hole that's about twice the size... First impressions without riding it: runs smoother at idle and revs quicker so off to the dyno next!

With regard to the 2-stroke bit: At the moment is stumbles and grumbles low down but as soon as it clears it's throat is picks up it's skirt and fuck's off like a scalded cat! Good fun! My concern is borewash due to the excess fuell and the risk of fouling the plugs. Mind you, it does start on 102 now and idles without problems so already some improvement! I've disabled the acceleration pump and adjusted the idlemixture, next step is to check fuelpressure as I believe it's flooding the carb.

Well if you don't mind me asking...any chance of sharing data with me? I can compare that to what's in the HSR at the moment and take if from there...

How much BHP were you running with the 45?

Think we have a misunderstanding with regards to the GJG bit, can't be arsed to explain but I misread an earlier post and two of our posts crossed so all is well! I'm pleased to see people repsond to question asked and I appreciate all the input! A thunderjet to get the midrange right? On the Mikuni you mean? I have one on the S&S but the S&S is overfuelling really badly so will need sorting: It has MAHOOSIVE jets, 1 to 2 psi static fuelpressure, a Thunderjet and the accelerator pump 3 full turns out and the enrichener 2 turns out! OVERKILL anyone? The fuell almost poured out the exhaust in liquid form...so to speak.

You know what would be interesting? Fitting a TB with 2 injectors and KMS management...draw through with EFI! Probably has been tried before?

But this topic isn't about 'things the bike did when GJG had it' so who cares? The bike has changed a lot since those day's!

I have a HSR45 for the bike as well as all the fitting so could easily swap over, I prefer making my own bits though as I'd like to improve on what is already there. I might stick the HSR back on for some low boost running around town untill I sort out the S&S properly. Mind you, it's lots better already after fiddling with it! Btw. the bike did do over 270 BHP

Well it's not a RayJay! It's a Turbonetics T3/4 hybrid with a 48AR STG 3 turbine and 50E blower. It's been dyno'd at 285 BHP at the rearwheel with the super E so around 300 at the crank. As for fuelling: Sean from Big CC seems to think the 45 will easily do it if the fuelentry is properly modified? You can also get floatbowlspacers although Sean reckons that won't work. Thing is the 'E is massivly overfuelling right now so i want to combat that. Won't a rising rate FPR sort things out?

LOL Thanks for that! I thought it should improve things somewhat, glad to have confirmation on that! The previous owner couldn't get the HSR to deliver enough fuel for 300 BHP, hence fitment of the S&S but as far as I'm aware 300 BHP should be no problem for the HSR? B.t.w. how did you get to 1460cc??

'Evening! I'm currently running a modified Super E on my draw through GSX but will convert it to run a Mikuni HSR 45 this winter. Now I'm thinking that the closer the carb is to the turbo, the better it'll be as far as response goes...what says you? Since I'd have to make a new adapter to fit the HSR I might as well make it a lot shorther than the one currently fitted...this will move the carb inwards so it sits underneath the fueltank. Might not be the pretiest but I'm thinking it should improve the lower RPM running...?

Hence my blanket idea...coating is an idea but I don't fancy taking the turbo apart just yet...

Good explanation that, thanks! As for heat: I've a massive blower that can produce the boost relatively easily, so heat not so much of an issue. However, radiant heat from the turbine is! I checked this, deffo coming from the turbine so I will fit reflective foil on the plenum to keep radiant heat out and will fit a turbo blanket as well. Don't get me wrong: it runs great, docile enough around town even though it's a bit of a pig off boost due to running very rich, and it's very quick up top as well (as in: fuck me, it's quick!!) but I'm just looking to improve slightly here and there to make it an even better package for road use.

It's not actually THAT bad...but it leaves somewhat to be desired... One point of attention is heat: I can feel the plenum heat up significantly which won't do it any favours so that will be adressed shortly. Can anybody tell me WHY they think the plenum should stay small? I think that, as long as the distance between the butterfly and the intake valves doesn't change, a larger airvolume would indeed aid off boost throttle response...

Errr....the make is Turbonetics, T4 blowerside, T3 exhaust side but the actual name of the turbo? Fuck knows....

Quick specs (full specs and pics in a month or so when I open a proper topic for the project) 1206 cc 10:1 Turbonetics T4/3 hybrid S&S Super D carb with thunderjet 285 BHP at the rear wheel, 212,3 NM at the rear wheel I know the fuel doesn't atomize very well on a draw through but I was thinking the available airvolume off-boost might be too small for the engine...? I'm thinking of fitting a MIkuni HSR45/48 with enlarged floatbowl as that is a much more sophisticated carb then the S&S (5 versus 3 carb areas to tune with much crisper response, atleast on N/A engines)

Goodmorning, I've a draw though bike that runs great on boost, 285 BHP at the rearwheel so fairly nippy. However, off boost it's not so good and part of that, in my opinion, is the fact that the plenum is rather small. So, I'd like to fit a larger one BUT due to space restrictions I can't just fit something larger. It'll have to be bigger on side than the other to get enough volume but I'm wondering if that's gonna harm the engine because of unequal airflow? What I mean is that it will be (for example) 1" deep on the left side (where the turbo is in the way) and 2" at the right side where there's more space. That's pretty much the only way I can increase plenum volume so.... Cheers for the advice!

What exactly do you mean by crossmember with reference to the intake? A 4-way divider in the intake or...?

Yes, that is the idea...I'm thinking it should produce more power and leave the engine running a little cooler...

Well, I might fabricate a 32 mm header and run them both on the same day and the same dyno...won't be for a while though

Turbo is a ceramic bearing Turbonetics T4/3 hybrid...it's currently running 24 psi of boost and pushes 300 BHP. It would be interesting to test both headers on the same day, on the same bench...I do have previous experience on a turbocharged car where fitting a larger bore exhaust system made it possible/nessecary to deliver a significant ammount of extra fuel to the engine and it made a good ammount of extra power.

No-one?

Right then, I've recently purchased an 1100 which has been fitted with a draw through turbo system. Now the headers are currently 28 mm BUT I'm considering upping them to 32 mm just because the material to do so is available. However, I'm wondering what effect you lot would expect to see from the change... On the one hand I'm assuming gasspeed will decrease due to the larger diameter, thus slowing down spool up on the turbo, however the gasvolume should increase so that part might level out. I'm figuring it will make it easier for the engine to breathe so temps should be lower and maybe it should make some more power... What do you think? Cheers, Steph