mik711
Oviraptor
Posts: 13
Bikes: gsxr 7/11, cagiva v raptor 1000
Reg: Oct 2, 2013 13:36:14 GMT
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Post by mik711 on Jan 7, 2014 21:23:37 GMT
I'm currently part way through a turbo build on my 1052 slabby. It,s had a complete bottom end rebuild (new shells, bearings, seals, all gaps plastiguaged), sent the top crankcase away to have the bores widened to accept the 1260 barrel liners. At the same time they removed the snapped cylinder stud and timeserted the hole. Now the DOH!! part of the rebuild. I bought Ape heavy duty studs and don,t remember where the shorter studs go! Anyone out there with the knowledge to impart would be most welcome. After that problem is solved its on with the cometic base gasket and barrels,drill out the snapped exhaust stud then have a look for some new cams. The originals are well marked up on the right hand side (lack of oil when parked on the sidestand i guess). The finished bike is gonna have a drawthru Garrett T3 and Mikuni hsr42 carb running about 6psi and i'm looking for about 200bhp at the wheel. I'm thinking that standard profile cams will be best but i'm happy to listen to any advice available. Right that's the end of the essay' feel free to take piss, criticise or offer advice. Cheers, mike.
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Post by nicearris on Jan 7, 2014 22:35:03 GMT
Just my tuppence worth but if i was you and had the engine broken down to the crank and was going to turbocharge it then i'd make the following changes, assuming your new pistons are forged and standard compression. Buy 2 base gaskets and a base spacer from debbens to bring your static compression ratio down to about 8.5:1 so you can use more boost (If your not going to use the air a T3 can produce then why use it?) If you do use more boost i would suggest an HSR45 may be more suitable.
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Post by bagm on Jan 8, 2014 19:09:13 GMT
bike looks gr8
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Post by captain chaos on Jan 8, 2014 19:41:00 GMT
Bike needs more headlights though. As far as i can see here, the shorter ones (no. 3) go on the rear between cil. 1 and 2 and cil. 3 and 4. But I don't know how accurate these part diagrams are.
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mik711
Oviraptor
Posts: 13
Bikes: gsxr 7/11, cagiva v raptor 1000
Reg: Oct 2, 2013 13:36:14 GMT
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Post by mik711 on Jan 8, 2014 20:36:42 GMT
I'm using the T3 turbo as i was given it , along with a draw thru plenum chamber. I've got a 2mm cometic base gasket to go on and wiseco pistons that take it out to about 1260cc. The plan was to build it and run about 6psi boost and hope for around 200bhp at the wheel. If the compression needs lowering i'll bang a thicker head gasket on. I'm new to this turbo business so it's a fairly steep learning curve.
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mik711
Oviraptor
Posts: 13
Bikes: gsxr 7/11, cagiva v raptor 1000
Reg: Oct 2, 2013 13:36:14 GMT
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Post by mik711 on Jan 8, 2014 20:38:41 GMT
P.S. Cheers capt. chaos i'll have a look tomorrow night and see what it looks like
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Post by CHR15 on Jan 8, 2014 20:50:45 GMT
if your building it from scratch and you need to lower the cr, do it with base gaskets rather than head gaskets.
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mik711
Oviraptor
Posts: 13
Bikes: gsxr 7/11, cagiva v raptor 1000
Reg: Oct 2, 2013 13:36:14 GMT
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Post by mik711 on Jan 8, 2014 21:06:03 GMT
Cheers CHR15 i just figured if i lowered the compression too much at the base gasket it would be a pain to strip down and put right. Why is it better to do it with the base gasket?
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Post by nicearris on Jan 8, 2014 21:16:44 GMT
You already have a base spacer!! Thats good. Now you have to find out what the compression ratio is for the Wiseco pistons you have. If they are around 10;1 then you could quite possibly build your engine up with a base gasket either side of your spacer, slot your cam wheels to dial in your cams 'coz you've altered your cylinder height with the spacer, double check your compression ratio with a syringe and a plastic plate and if your static comp ratio is around 8 to one then your good for 15psi boost(boost is addictive!!) BUT if those pistons you have are the really high comp ratio ones at 13 to 1 then with the same procedure as above i would estimate you would be limited to around 10psi boost. You need to know what comp ratio those pistons are before you do anything then you need to get familiar with physically checking your engines comp ratio and valve piston clearances. Its all a learning curve. And as Chr1s says, best to alter comp ratio on the base gaskets as the head gaskets bugger up your squish.
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mik711
Oviraptor
Posts: 13
Bikes: gsxr 7/11, cagiva v raptor 1000
Reg: Oct 2, 2013 13:36:14 GMT
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Post by mik711 on Jan 8, 2014 21:39:34 GMT
Holy shit, so much for keeping it simple!! The wiseco pistons and barrels supposedely came off steve burns mission improbable bike and the last time they were on an engine they put out 160bhp with lots of smoke.Barrels have been honed and new rings ready to be fitted. the pistons have had the crowns shaved at some time in the past and i was hoping that the 2mm spacer would be enough to get it on the road.I've read on the old site that standard comp is good enough at low boost pressures.
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Post by nicearris on Jan 8, 2014 22:02:45 GMT
So you've no idea what comp ratio you will end up with!!!!!!!!! smileychair You need to know how much boost you want to run and what compression ratio you need to achieve that!! I agree that a standard engine properly set up will take 6 psi but at the moment you have no idea what you are going to end up with with the configuration you have described. Checking the capacity of a barrel and a head is not difficult. As with everything, its only difficult the first time. Its a simple process detailed in several books on tuning (I hesitate to say "on the interweb"as a lot of bollox is spoken on the net....HELL, I might be talking bollox to you but you dont know!!!!!!!) Anyway, keep going. An awful lot of people want to build a turbocharged motorbike but very few start it and even fewer finish one!! And just in case you are getting complacent with the whols turbo thing i'll just ask....Is the T3 you have been given...carbon sealed? Coz if it isnt, you cant run a draw thru without it and you've got another expense coming!!
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Post by duckndive on Jan 8, 2014 22:25:34 GMT
The trouble with boost is it becomes addictive.... 6psi becomes 8psi then 10psi then race gas and 12psi...etc etc...you just cant get enough... Do a dry build of the engine to find the deck height and as already said find out the head chamber cc .. that will then allow you to work out the CR as it is.....you can then work out whats needed to get to your target CR.... 8.5:1 is good for a street driven draw thru and will run fine at 6-10 psi on superpi55 after that you will need race gas if you want to keep the pistons in one piece....... Build it right and build it once ...
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mik711
Oviraptor
Posts: 13
Bikes: gsxr 7/11, cagiva v raptor 1000
Reg: Oct 2, 2013 13:36:14 GMT
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Post by mik711 on Jan 8, 2014 22:30:55 GMT
The turbo was re-furbed and carbon sealed as the first job when i was given it. The pistons have had the tops shaved and a 2mm spacer is going under the barrels. I will be running 6psi boost. If a standard engine can take this pressure (if it's in good nick) then surely with spacer etc. my engine is going to have less compression than standard and so should take it too? Please don't think i'm being argumentative, i've just no experience at this and figured to just try and keep it simple .By the way it's going to be a road bike and i don't like extended swingarms so is it going to be too much??
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Post by CHR15 on Jan 8, 2014 22:50:58 GMT
lifting the barrels via the base gasket will affect squish just the same as doing it with a thicker headgasket.
the reason for doing it via the base, is that the thicker something becomes the less pliable it becomes. more like a head spacer than a head gasket. you also run the increased risk of it blowing out as the surface area on the inner face of the gasket is increased.
if i was doing it, i would start off by fitting a piston and rod, with the base spacer plate and no base gaskets. you can then see how far down the bore the piston sits at tdc and work out the volume.
if there flat top, its nice and easy, (pi x 1/2 bore^2)x depth, if not, you'll need to work out the volume of the cylinder and the volume of the piston below its uppermost surface and add them together.
once you've done that you can flip the head upside down with the valves and a plug in, get a piece of perspex, drill a little hole in the middle and wipe some vasaline on one side, put it on one of the combustion chambers and fill it with 2t oil using a syringe (a burette is better) you've now got the volume of the head.
use (pi x 1/2 bore^2)x stroke to work out the displacement volume.
a cometic mls headgasket is 0.65mm thick when compressed. (pi x 1/2 bore^2)x 0.6 to work out the headgasket volume.
genuine basegaskets are 0.3mm thick when compressed. (pi x 1/2 bore^2)x 0.3 to work out the basegasket volume.
now add the displacement volume + the head volume + the cylinder / piston volume + the headgasket volume + the basegasket volume to give you the swept volume.
add the head volume + the cylinder / piston volume + the headgasket volume + the basegasket volume to give you the clearance volume.
now do swept volume / clearance volume to give you your final c/r
bear in mind, you also need to adjust for a nice squish band (1.1-1.2mm is a nice number)
to work out the squish take the distance from the tallest part of the piston at tdc to the face of the block + the headgasket thickness.
add or minus base gaskets to get that figure right. then re work out the c/r taking into account the new number of base gaskets.
easy peasy.
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Post by nicearris on Jan 9, 2014 11:50:36 GMT
To qualify my statement on squish adjustment. Yes, the squish clearance can be increased via either the base or head but for best squishband angle, in my opinion, its best to do it via base as you said. Just a wee note of caution mik, unless you are some sort of nutter on the road then you will probably only ever be using boost about 5% of your riding time if its a road bike so watch you dont set your comp ratio too low coz it'll make the bike a real slug to ride off boost!!. So there ya go mik711. As above, easy peasy Lots of opinions and hopefully you found out where your studs go. Get on with it and keep us posted.
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