Q's about proposed KZ750 EFI turbo engine

So I'm a mechanical engineering student that has made a buggy with a kz750 F LTD engine and I'm thinking about making big changes to the engine to attempt to make more power. I am planning on replacing my carburetors for fuel injection and add a turbo while I am at it. Id be aiming for a max hp of ~120. I'll be using a genuine Garrett gt1241 turbo for the conversion and I'm modifying the throttle bodies of a 2005 Yamaha r6. I have a spare engine which I plan to use the head of because of its mechanical tachometer which I should be able to use as a cam position sensor. Apologies that parts of my post may overlap with other posts I've seen on the site. here comes my list of questions so far:

• I have realized I am essentially recreating the GPZ750 turbo engine so what are the differences between the engine internals? I know they have more aggressive cams but what else? are there any compatible parts I should look into buying?
• I know the GPZ turbo has lower compression than the stock kz750, should I lower it to be on the safe side? I know in the automotive world some opt to just double up head gaskets to lower compression. 
• because of extra heat from the turbo and reduced air flow because the engine is blocked by the rider I want to install a large oil cooler to help the engine stay cool. If I install a significantly large oil cooler I'm worried about how restrictive the oiling system will be with both the turbo and large oil cooler. Does anyone know if anyone has had problems with the oil pump being too weak? Has anyone installed a scavenging pump on their bike to combat a restrictive oiling system?
• switching to an EFI system will I need to upgrade my generator?
• Does the GPZ turbo have a stronger transmission to deal with the extra torque the turbo gives? If so, how can I improve my chances of not blowing mine to pieces?
• Are there any other performance modifications I should look into?
• Is there anything else I should know before getting sucked too far down the rabbit hole? I'm aware there is quite a lot of work to be done fyi

Any and all input is appreciated! thanks for your help in advance.

From what I've read here, the turbo cams are closer to 650 than GPz.

An oil pan from a GPz, with cooler take-off ports, was a straight bolt on with my 750E engine.  

Member Daftrusty installed a ZX7 oil pump and starter clutch on his hot rod 750 engine.  You may want to look up his old threads for info.

An engineer with a response from an engineer (ED, Hi ED). Might i be Your conscious, i'm sure the wheels are-a-turning in the brain!! I used to sell piles of the old air cooled KZ1000ST engines to fellas running Mini-Sprints 1/4 scale track cars back in the day. But they too figured it out in short order when water-cooled engines/proven designs came out. This might date me but this was waay back in the early 90's. So..why recreate a scenario proven to be addled with cooling issues, many persons have tried it before your interest, and moved-on. Ya know those "new" shifter watercooled powerplants from all the manufactures make waay more HP/Torque then spending thousands of dollars duplicating the same with an old KZ750 engine. Soo many options too and conservatively priced. Think about it???     

Or, if You're clever check-out the selection of watercraft engines. They have been making Kawasaki H2R power for years, way before the "touted" bike came out. Not Your Dad's Evinrude/Johnson version with cracked rods two stroke either. And by cracked rods i don't mean broken stuff. That's how they were finished, ha. 

Pretty much everything is different on the turbo engine. Sure you can do it but dont expect it last long without having a meltdown. Lots of info here on the turbo site.

750turbo.com - Index page

Interesting project, couple of things I would point out. Your second point ref lowering the compression by using multiple head gaskets "NO" if somebody suggested this the should "have their tool box welded shut" the right way to do it is first calculate how much you want to increase the combustion chamber by then get a spacer cut using the "base gasket" as a pattern so in effect you are lifting the cylinders up a little (if you are planning to run any kind of boost I would think around 8:1 would be about right)
In any bike powered 4 wheeler the weak point will always be the clutch (more weight and 2 driven wheels) once the clutch is uprated the next weak point will be the trans, then the primary drive (you get the idea) unless you really want to do this "for the doing" I'm with Clay, a water cooled motor from a later 750 sports bike will make the power you are looking for "out of the box" and won't suffer the air flow issues air cooled powered cars suffer with.(just the trans to worry about then but since it was made for the power output of the motor you have at least got a fighting chance) Just my opinion obviously but I think you are in danger of sinking "a lot of dollars" into this

As for my reason to why I am using the KZ750 shaft I have a conventional drivetrain, no chains that is. The only modern motorcycle that I know of that is a shaft drive is the goldwing, and I'd like to keep to an inline engine configuration. In short I've kinda fallen in love with the KZ platform and would like to see how far I can push it. I will attempt to explain my thought process for the issues below:

Cooling:

• I know Suzuki was able to make a high performance motor with the '86 GSX-R 1100 that was oil cooled. They had a high performance oiling system but it makes me reason that if I get enough volumetric flow of oil in combination with a large enough oil cooler I should be fine with cooling. Its controversial but I know some opt for a thinner weight oil in racing machines and go ham on cooling to run an engine cooler but within the same oil viscosity range. I am also considering adding a meth/water injection system to sweat the cylinders from the inside which is pretty common with turbo builds. 

Transmission:

• When I was doing research on turbo conversions (if I remember correctly) all people tend to recommend is to replace all the bearings so I kind of assumed that should be all I should have to do. I am part of an FSAE club on my campus in which we design, build, and compete in competition with a purpose built race car. We use a 2005 r6 motor that we've done plenty of modification to that has a higher torque output than the stock bike yet we don't touch the transmission (apart from removing first gear). I understand the problem with clutch slip  but what else should I have to do to ensure good transmission health? Does anyone have horror stories about high power KZ750's tranny's blowing?

Thanks for the input so far guys and keep it coming! I'll make sure to post on the 750turbo forum to see what they have for me as well.

I'm interested to watch this develop

Dunemaster post=910298 userid=65727As for my reason to why I am using the KZ750 shaft I have a conventional drivetrain, no chains that is.
 

First off, please post many many photos of your buggy. We'd love to see the details.

Second, you should absolutely do an EFI and turbo conversion on your KZ engine.  Why not?  Even if you blow it up, the process of getting it built and tuned and running will have provided you with a huge amount of knowledge and experience.  And you already have the engine in the buggy right?  Just do it.

Oh.  If you do want a later KZ650/750 oil pan with the oil cooler taps, I have one sitting around I'd be happy to send to you.

Dunemaster post=910298 userid=65727 

• I know Suzuki was able to make a high performance motor with the '86 GSX-R 1100 that was oil cooled. They had a high performance oiling system but it makes me reason that if I get enough volumetric flow of oil in combination with a large enough oil cooler I should be fine with cooling.

That's not necessarily true. The SACS GSXR engines were designed from the ground up with oil cooling in mind. They had internal oil sprayers to cool the underside of the pistons, and sprayers in the head to cool the combustion chambers. That type of targeted oil cooling does not exist in the KZ engine. Even the oil cooler itself was an afterthought, added much later in the engines evolution.  Even if you keep the oil very cool, it's not necessarily going to carry heat away from the top of the cylinder (piston crown and combustion chamber) fast enough to keep the engine cool.

en.wikipedia.org/wiki/Suzuki_Advanced_Cooling_System

The SACS system uses high volumes of engine oil aimed at strategic points of the engine, like the top of the combustion chamber, which are not typically well served by air cooling alone. In order to provide enough oil for both cooling and lubrication, the system uses a double-chamber oil pump, using the high-pressure side for lubrication of the parts (crankshaft, connecting rods, valvetrain), while the low-pressure, high-volume side provides oil to the cooling and filtering circuit. The oil removes heat from hot engine parts through direct contact, is pumped away and subsequently routed through the oil filter, followed by routing through an oil cooler before being returned to the main sump.

 

Dunemaster post=910269 userid=65727

• I have realized I am essentially recreating the GPZ750 turbo engine so what are the differences between the engine internals? I know they have more aggressive cams but what else? are there any compatible parts I should look into buying?
• I know the GPZ turbo has lower compression than the stock kz750, should I lower it to be on the safe side? I know in the automotive world some opt to just double up head gaskets to lower compression. 
• because of extra heat from the turbo and reduced air flow because the engine is blocked by the rider I want to install a large oil cooler to help the engine stay cool. If I install a significantly large oil cooler I'm worried about how restrictive the oiling system will be with both the turbo and large oil cooler. Does anyone know if anyone has had problems with the oil pump being too weak? Has anyone installed a scavenging pump on their bike to combat a restrictive oiling system?
• switching to an EFI system will I need to upgrade my generator?
• Does the GPZ turbo have a stronger transmission to deal with the extra torque the turbo gives? If so, how can I improve my chances of not blowing mine to pieces?
• Are there any other performance modifications I should look into?
• Is there anything else I should know before getting sucked too far down the rabbit hole? I'm aware there is quite a lot of work to be done fyi

You should start by going on here :
www.750turbo.com/

The big differences on the GPZ750 turbo engine are 16 mm wrist pins, M7 rod bolts, and a scavenge oil pump system (to feed turbo) except for the low compression pistons it is very similar to a gas 750 engine. The GPZ cams only have about .030" more lift than KZ cams, and higher lift cams are not really necessary on a turbo engine (but good if you can get them)
Don't do any porting on the cylinder head as that may ruin it, only port or big valve the exhaust side if you need to.
The KZ engine has a lower compression ratio compared to a GPZ gas engine so I don't expect you would benefit from a piston swap.
Forged pistons would be a good choice but getting pricey new, are far as I know only the 810cc available for 15mm pin. Stock GPZ turbo pistons are cast (thick dome?) so they must be OK for limited boost - go on turbo that web site to investigate.
Stock GPZ750 Turbo HP was claimed 112 to the crank so maybe 100HP at the wheel with stock engine internals.
If you expecting to turn up boost to output 120HP you need to run a MLS head gasket and a quality base gasket. You should upgrade to APE aftermarket cylinder studs and nuts at the least.
You need to upgrade the oil pump to a ZR7 unit as the make more pressure, a must for turbo applications.
Make sure you run a tripac ATV fan on the oil cooler, a intercooler would also be a good idea if you have room.
Get a GPZ750 oil pan as they are already drilled out for a oil cooler. You can also drill out the stock oil pan at the front as well.
Cooler lines for a 750 should be limited to -6AN, don't think you need bigger lines, that is a common mistake.
Don't run a old stock ECU to control the injection (no way to control) get a modern ECU like a Microsquirt or any other brand name, much easier to work with and make changes to the tuning maps.
You need to find out amp draw on all electrics to make sure you not going to have to run a non stock alternator. The big draw will be the fuel pump, if you can run a in tank pump that would be good as the external pumps draw way more amps.  A crank driven non stock alternator will also reduce HP.
GPZ750 transmissions come stock from the factory with undercut dogs to aid in high RPM shifting. If your on a budget you could DIY the undercutting of the gears on a conventional mill using a rotary table.
You need to check to see that your clutch hub is not loose, if so split it apart, change the rubbers, and weld it back up. Use stock clutch plates and aftermarket HD springs with  APE pusher, should be good to go.

Start by going on the UK Turbo web site, lots of guys have already done DIY conversions from gas engine to turbo/EFI engine. There are also lots of examples on YouTube.
 

This member (RIP) did a carb/turbo conversion :

www.kzrider.com/forum/11-projects/423436...-turbo-kz650?start=0

Lots of good info there plus he was trying to get a DIY scavenge oil pump working, not sure if it working or not because he got sick

I am not a turbo expert by any means but have collected some information over the years. I was going to put a Eaton supercharger on one of my builds (sort of similar) so I have investigated putting power adders on Z1 and 650/750 engines in the past.

Dunemaster post=910298 userid=65727Cooling:

• I know Suzuki was able to make a high performance motor with the '86 GSX-R 1100 that was oil cooled. They had a high performance oiling system but it makes me reason that if I get enough volumetric flow of oil in combination with a large enough oil cooler I should be fine with cooling. Its controversial but I know some opt for a thinner weight oil in racing machines and go ham on cooling to run an engine cooler but within the same oil viscosity range. I am also considering adding a meth/water injection system to sweat the cylinders from the inside which is pretty common with turbo builds. 

Transmission:

• When I was doing research on turbo conversions (if I remember correctly) all people tend to recommend is to replace all the bearings so I kind of assumed that should be all I should have to do. I am part of an FSAE club on my campus in which we design, build, and compete in competition with a purpose built race car. We use a 2005 r6 motor that we've done plenty of modification to that has a higher torque output than the stock bike yet we don't touch the transmission (apart from removing first gear). I understand the problem with clutch slip  but what else should I have to do to ensure good transmission health? Does anyone have horror stories about high power KZ750's tranny's blowing?

Water/alk injection into the plenum to cool the intake charge is a good idea especially if you have limited air flow.
Stock Kawi transmissions are basically bullet proof. Only Z1 drag bikes use aftermarket gears, normally replacing 2nd gears on bikes over 160-180HP (big slick tire bikes) they do replace other gears on engines making over 300HP.
I was told by a Kawi Top Fuel guy that stock case castings are good to about 500HP.
The 650/750 series bikes were designed much better, the same head engineer worked on the Z1, so the 650/750's had upgraded systems.
I run a stock transmission on my 650 slick tire drag bike (831cc alcohol injected) never had a trans gear issue.