slingy1157
-
Posts
223 -
Joined
-
Last visited
Content Type
Profiles
Forums
Events
Posts posted by slingy1157
-
-
My short stroke build thread is on here somewhere.
Wiseco listed the largest pistons for these engines with a rebore at 76mm. So I ended up finding ZX10 pistons. Think mine were 05 model. These are factory forged flat topped pistons but I think 17mm wrist pin. So like you stated I got the rods bronze bushed to suit that pin size. Deck height was pretty good but very slightly low. This combined with the flat top and larger valve pockets gave about an 8-1 cr. The block could be skimmed to perfect deck height and run one layer of the multy layer steel head gasket would help get it back to 8.5-1.
being 76mm means you can run a 1052cc head gasket too which is helpful. This gives an 813cc engine with turbo friendly CR and forged pistons. Mine were $40 with the rods, combined with $150 for the rod sleeving and then a rebore, so pretty good value for money.
I think the rods will be fine for 200hp. Studs is the problem. You can use 1052 ARP studs which are too long. But there is room in the head and around the cams to machine up very thick washers to make them work. Tip- replace the studs when your cases are apart getting the rods sleeved so when the old ones snap off in the cases it’s easier to get them fixed lol-
2
-
-
On 7/28/2018 at 7:49 AM, davecara said:
@slingy1157did his 750 efi turbo using zx10 pistons iirc
Yep. Mine was stock shortstroke, bored to 76mm. Stock rods sleave to 17mm? I think. 04 zx10 pistons. Deck height was mere perfect from memory and used a stock 1052 head gasket. The big problem was CR. This was about 7.5-1, low even for turbo use, and this was already with a dot head obviously. CR would improve with a longer stroke a bit but I doubt a head skim would gain enough for NA running
-
Mine was a short stroke 750 slingshot. Didnt have much luck with the carbs (just me) so went efi, then did ny own 813cc big bore with zx10 pistons. Only made about 130bhp at the rear wheel on 10psi, mainly because the zx10 pistons dropped the the cr too much so that would have dropped the na power starting point. Even though, SO much fun to ride, like a giant 2 stroke, without being silly power so could still wind it on and have some fun.
Also here in Oz on ASF site, Latheboy has a longstroke (same as your engine basically) slingshot running blow through carb, t25 on 10 psi i think, stock motor, 1100 clutch and making the 150bhp ish by memory. He does work in a dyno shop so it has had endless dyno time to dial it in perfect. Pretty sure its running different jets in each carb to even fueling to air delivery by plenum etc. But still pretty impressive for a stock motor. I think he blew a motor up at the drags, but was back running again quick as, cause 750 motors are ten a penny and no prepping other than n clutch needed lol
-
Is that a FBM kit?
Looks really good by the way
-
16 hours ago, davecara said:
Nice one Jack, hows your 750 going? Still havent got my EFi'd 750 running yet. Kept losing sync with the crank pulse, it was down to wiring and 3 duff batteries in the end. Gonna get back on with it in the new year
Hi dave. The 750 went 1052, then 1157 then sold so i no longer have it.
But definitely get back to yours and get it sorted. Efi rocks and ironically was the one element that always worked ok on all 3 engines lol
-
Got my gsxr750 short stroke rods bronze sleeved to fit zx10 pistons. No dramas woth it
-
1
-
-
11 hours ago, luke2152 said:
Bike is running great. Have put in couple of hundred miles on it. Mid range torque is great at 0.5bar boost. Keeping out of the top end revs til its fully run in and I have a decent AFR gauge. Think I have a bit of oil leaking from under alternator. Hard to tell exactly but I'm guessing there's a big o ring where the alternator goes into the crankcase? Also my header bolts keep coming loose. I used copper doughnut style gaskets. Will they settle down and stop coming loose after a few more heat cycles or should I use a pressed wire OEM type gasket.
I never had problems with oem style gaskets
-
Yep. Datalogs will tell you everything you need to answer this. What does the map sensor read when static? And what map sensor do you have and is the right one selected to suit in the software. If a gm style map sensor, alot advertised as 3 bar aren't. You need to google the part number and check. 1 , 2 and 3 bar gm map sensor all look the same so be carefull.
-
I worked with a guy here in oz, and he built a cheap drag car with a 4 cylinder motor, mechanical FI and a huge turbo. He actually filled the block and head water passages with resin to stiffen the block. And as has been said, i do remember him saying there was no over heating problems because of the methanol .
Mmmmmm........Resin filled methanol WP running big boost?
-
1
-
-
On 5/24/2017 at 2:03 AM, Gixer1460 said:
Because going full control really needs a crank trigger with more resolution than 4 odd teeth. The Dyna solution is a bit ghetto / simplistic but it works if you accept the limitations - I believe it group fires two cylinder injectors - like wasted spark but with fuel!
On a normally aspirated bike you could probably go really ghetto and use the tach out of the oem ignition module as the input reference to the mS. Then use the tach out from the mS to run the tacho again for fuel only. Save trying to diode and resistor a clean tach signal off the coil negatives.
I wonder if you could use this as a crank signal and by adding a cam sensor then use the Ms for fuel and spark with the stock trigger wheel? Interesting......... .
-
Good work. If the fuel height is about the same as gravity i dont you should lower the float height for the moment. Just do what your talking about and change one or 2 things at a time.
-
1
-
-
On 6/5/2017 at 4:23 AM, luke2152 said:
Happy to say that when I moved the temp sensor to the sump the temperature was a much happier (and more stable) 105 degrees or so. I knew the head was the hottest part but had no idea it was that much hotter. I put a chain on and took it out for a few laps of the carpark and and even with no tuning adjustments it felt quite well behaved. My latest problem is the trigger wheel. It started first time with a well charged battery but its a bastard to start with a half charged battery because at low cranking speeds its having trouble syncing. I'm thinking I might remove another tooth to make a 35-2 with a more pronounced gap. But I might pose that question to the megasquirt forum.
That is actually a really good idea. Theres no reason why it couldnt be a like a 36-6 wheel and have 6 missing teeth really. As long the first tooth after the gap is still 5 teeth or more before TDC so it can work out the timing nicely for 1 and 4 it dosnt really matter.
I still like the 36 tooth wheels as it keeps the math all nice and easy with 10deg per tooth and all that and gives really good timing reference to the ecu. And as one of the main issues is sync durring cranking with these then why not make the gap bigger so absolutely unmistakable at cranking.
You can set it to whatever you want in TS so thats no drama as long as the teeth on the wheel are all the same size and evenly spaced to begin with it dosnt matter how many teeth get removed qithin reason to make the gap.
-
Ok so to throw another slight spanner in the works here with the gravity test.
The gravity pressure at the floatvalve is directly proportional to the height of the fuel not the volume.
So an 8mm pipe with the end held 1metre above carbs and then filled with fuel will give the same pressure as a 5 litre fuel tank full of fuel with the fuel level 1metre above the carbs.
So the key point here when doing a gravity test is that whatever fuel tank you are using, the fuel level needs to be about where it would be if it were in the oem tank on the bike.
So if using a temporary tank, it would be better hung from the bars or similar to better replicate the oem setup. If you have it hung too high you might get a couple of psi of gravity pressure anyway. Which is not what this test is about. Its about trying to get an oem base line setting so you know what to adjust to compensate for the pressure.
-
1
-
-
13 hours ago, El Gringo said:
I also think it might be worth replacing the float needles, they don't look to have any wear on the tips but the sides are a little shiny
Yeah mine looked fine but didnt stop flooding untill i replaced all 4. An expensive exercise on the old bst36 carbs as you had to buy the whole plastic float and frame assembly to get them .
Carbs really do need to be in 100% as new condition, not just clean. ANY wear seems to be greatly exaggerated by the fuel pressure and boost.
-
1
-
-
Good work mate. Cant beat actually seeing what is going on. I would be questioning those gravity fed levels. I would of thought, looking at the carb design that the gravity level would be about halfway between the two marks you have. So they seem rather low. The 2.5psi marks are about what i would have expected. On my carby build using a modified webber fpr i think, i drilled out the fpr return right from the seat through, as i had an 8mm return line but couldnt get the pressure below about 2.5 either as the actual seat hole was about 4mm and was having flooding issues. I also ended up leaving the spring out.
And i used 2 relays to run the pump, so it only ran while the engine was cranking or running. Much safer as if you drop the bike the pump will stop and not pump fuel everywhere as well as not subjecting the carbs to pump pressure for any longer than necessary and I'm not a fan of listening to winey pumps without the engine running lol
-
1
-
-
3 hours ago, El Gringo said:
Thanks for the info Slingy,
They are GK76a carbs so that could well be the issue, i think i'm going to go back to 20-21 and try the clear pipe idea and see what it's doing on the pump/regulator.
I had it running again over the weekend, seems like it had eaten a couple of the plugs.
At one point it sounded like it was trying to chime in on all 4 cylinders - which was odd as i thought it already was running on all 4?!
Carbs are now fully apart again to be cleaned and float heights re set. Will also get another fresh set of plugs
I shall not be beaten!
I found new old stock plugs on Eblag from the us and ended up buying a dozen at a time as ngk's seem to die for a pass time as has already been mentioned. I could even park mine up running good and come back to it a few weeks later and struggle to get it running due to dead plugs.
On a side note, i had an old dirt bike with a self tuned 2 stroke. It ran great on an old Champion plug i plagged from an ancient boat engine. Twice i thought, i really should give it the propper plug, and twice they died within literally seconds of running. I ended up just running the old Champion plug which it just bloody loved for some reason.
Keep at it. If it was easy, everyone would do it lol
-
2
-
-
Are running the GK76a carbs?
If so the standard float height is 20mm. Looking at the float design and measuring point, at 23mm there is a real chance the float is jammed between the float bowl and the valve and there is no movement left to let fuel in.
-
1
-
-
With the float height 2 things to remember.
1. You lower the float height because the fuel pressure has increased from virtually only 0.25 psi of gravity pressure from the tank to 2psi of regulated pump pressure.
So now more force is required on the float valve to hold back the fuel. This extra force can only be generated by the float displacing more fuel to create more buoyancy . So imagine, for a given set float height, as the fuel pressure goes up, the fuel height in the bowl will rise as the buoyancy of the float needs to match the force required to hold the float valve shut. So by lowering the float height ( as viewed durring normal opperation or an increase in the float height as measured with the carb upside down and bowl off) at increased fuel pressure we are only really returning the fuel height in the bowl closer to factory levels and definitely should not be lowering the fuel level.
2. Every type of carb will vary wildly with how they handle the fuel pressure. One of the best ways i think is to put a bit of clear pipe on the bowl drain
And open the drain with the pipe run up the side of the bowl. With everything factory, mark the fuel height on the outside of the bowl. Then with reg and pump running, use the clear pipe and adjust the float to try and match the original mark or just slightly higher. Should be alot quicker as saving any guess work. You will see what is happening and it will be set correct for any given pump, reg gauge, combo .
-
2
-
-
Thats right where the header pipes are though. There is only so much space to play with at times.
-
14 hours ago, Gixer1460 said:
I doubt it, as why would you have a hose clamp end, if it screwed into a rail? The thread is std. metric and clamps the reg to a bracket where ever you want it.
No i mean the regulator thst SRR is using is this one.
Which is designed to fit into a purpose designed rail but SRR is using it With a housing to give it hose bard connections. Better to just use a reg with hose barb connections is all i was getting at
-
Nope your right, the return line is the centre one , my bad.
The fuel comes in from the rail from the side and pressurises the underside of the diaphram. Once the pressure is high enough to lift the diaphram the adjoined centre needle valve lifts and lets fuel pass back to the tank via the centre connection.
But i wouldnt like to rely on that for this setup as thats a reg normally fitted staight into a purpose designed fuel rail that had both inlet and return together on the bottom, now mounted in some sort of custom adapter. So anything coukd be happening.
-
I'd be heading off the the nearest self serve auto wreckers and grab something like this for a few quid
Look at this on Eblag http://www.Eblag.com.au/itm/162087962374
Plenty similar out there.
Like its been said, I take it the return line is on the otherside of the fitting?
-
I wired mine through 2 relays. One gounded by the oil pressure switch ( using the normally closed contact), and one powered off the starter relay (using the normally open contact in parallel with the above normally closed contact) so the pump would run when the engine was cranking to assist with priming etc and then when the engine was running due to the oil light going out. Worked well and meant as soon as the engine was stopped the pumo stopped so no noisy pump running and could have ignition on for testing stuff etc. Plus in the event of a crash it woukd stop the puml as well. I have a diagram i can post if intersted
-
Brilliant, brilliant, brilliant. Cool solution and excellent engineering skills. As Maggot said, " Gold"
turbo/EFI setup
in Forced Induction
Posted
I didn’t weld mine. Just a machined press fit is fine. There is no load on it essentially and the hardness of the 2 materials is very similar so the expansion rates should be close so the press fit resistance should be the same regardless of temperature. Plus if you want to change the missing tooth spacing to aid starting or anything, you can.