Garrett T25 Turbo Build

[plattey]

Actually, oil will run through the water cooling jackets to aid in cooling the turbo. I currently have an oil cooler (about 4"x4"x2" thick) but I'd like to run a larger one instead. This is another area where creative packaging will have to be used

 

[Focusinprogress]

so you're going to run two oil feeds into the turbo and two oil drains out?

 

[plattey]

Yes, one circuit runs outside the bearing system for cooling while the other runs inside to keep the bearings alive. The cooling circuit will also run in a loop with an oil cooler.

 

[zmaxmotorsports]

I know its a little late in the process but have you considered a smaller turbo?
That T25 might be better suited for a larger motor,Im building a motor for a customer right now Kawasaki 1075 that he was wanting to use a T25 on also but we decided it was too big for his motor so we're going to be using a different style once we get further into the build process.
Most of the motors I build are in the 1197 plus range so Im still in the learning stages of sizing stuff up for smaller motors

 

[plattey]

Haha, yup it's crossed my mind. I took a ice design class before I graduated and for a final project my group sized turbo's for 3 vehicles. One of them was the dearly beloved xs lol. It was mostly theoretical (temperature after compressor was assumed to 150F, R was set to 53.3 ft*lbf/lbm*R, volumetric efficiency to 90%, brake specific fuel consumption to 215 grams of fuel per hp hr, max rpm set to 7K rpm) after the calcs got a air mass flow rate of about 7.4 lbms of air per min at 23.4 psi. Went to Garrett's website and matched those #'s with their GT1544 (not the T25). Ended up getting a t25 from a friend for porting a set of gm3800 heads for him. Looked up the t25 compressor map using those #'s found from the project and found that the T25 may work ok (runs close to the surge line of the turbo but for now the turbo's limited to 10 psi so we'll see how she runs). Yes, there are better turbo's out there that would work better on the xs650 but after this build we'll find out for sure if the T25 is on that list of turbos that work or not
In the meantime, got some more work done on the bike. The parts from summit came in last week and got the fuel pressure regulator and fuel pump mounted. Also ran vacuum lines for the bov, boost gauge, and the fuel pressure regulator.

 

[Focusinprogress]

it'll be very interesting to see how this works out!

 

[plattey]

Got some more work done last night and ordered AN fittings for the fuel system yesterday. I knew AN fittings were pricey but wow! $40 for 4 fittings? Whoever's running that show is makin' bank! lol
As far as work, I mocked up the downpipe last night and was making a wastgate pipe that would intersect with the main downpipe early in the bend. Referenced the book and too early of an intersection between the downpipe and wastegate pipe would impair flow from the turbine. I'll order a 1 7/8" mandrel bent pipe with matching radius as the downpipe to make it flow well. Also made a bezel for the boost gauge and paint it once it warms up or I get access to an area that's more ventilated than my apartment!

 

[plattey]

Finished plumbing the fuel system last night with the an fittings and fuel injection hose. The fuel pressure regulator is a bypass type so a return line had to be tee'd in before the fuel pump inlet.

 

[wallywheels]

Do you have a time frame you would like to have it running by? and if so how soon? really excited to see how it plays out.

 

[plattey]

I just ordered the oil scavenge pump and that'll be at my doorstep next monday. I'll have to plumb the oil system to lubricate the turbo bearings and cool it as well. Then I have to order a bigger battery and wire everything up. Then after that I should be able to start it up and see how it runs. If it runs well and spools well, then it's time for tuning and run it on low boost for a little bit. I'm hoping that it'll be ready to start in a little less than a month.

 

[plattey]

The turbo scavenge oil pump cam in last friday and I got to work on it this weekend and last night. Mounted the oil pump just in front of the rear wheel and plumbed up the outlet to the turbo oil supply line for the bearings and the cooling jacket. Also picked up some oil cooler mounting zip ties and mounted the oil cooler where the side reflector markers mounted. I'm gonna look for an inline screen/filter that can be put in line with the oil pump inlet to prevent debris from entering the gear pump. Most of the fabrication work is complete, just have to mount the battery, wiring, drill and tap a location for an oil supply line to the oil pump, plumb in the oil cooler, and then the hard part.........tuning.

 

[plattey]

Fabrication is done! Got a lot done this weekend. Finished the wiring for the oil and fuel pumps and moved the master kill switch. Also finished plumbing the oil cooler and made a restrictor system using a vm carb main jet. The turbo journal bearing feed line and the cooler line both receive oil from the auxiliary oil pump. The banjo bolt for the journal bearing feed has a set diameter (without drilling it out to a larger size) so a restriction to the oil cooler line is put in place to force more oil flow through the bearings instead of the cooler. I'll be doing a test to verify that the turbo is getting about a half gallon/minute of oil flow. If not, then drill out the banjo bolt more or restrict the oil cooler more. Hoping to test fire it in the next week or two

 

[plattey]

So I made a mistake. After talking with co-workers about the blow through setup, I ran plumbing for the float bowl vents incorrectly. The external float bowl vents need to see the same pressure as the carburetor's intake bell, not get plugged. I thought that the float bowl vents were located in the intake bell, but there's only pressure references for the pilot jet, needle jet, and the choke circuit. So last night I tapped a 1/8" NPT fitting and T'd in the outside external float bowl vents from the two carbs. They should now see the same pressure as the intake bell and flow fuel correctly through the carb.

 

[Tron]

Any updates plattey?

 

[plattey]

Yup, the weather warmed up a little here in Osceola wi and I moved the bike out with the help of a co worker. Went to the gas station and bought some race 110 and filled up the tank and started kicking. Learned 3 things:
1. The needle and seats in the current carbs are too large and 5 psi of fuel pressure will push past the needle assembly and flood the engine with fuel. The current needle and seat assembly are 3.3's and 2.5's can be installed. There are 1.5's available but not surenif they will fit the VM 34's since they come in the vm28's.
2. The electrical load is too large for the 5ah battery and the stock charging system is marginal. For now going to source a ballistic battery rated for 15ah to help that issue. Should really opt for a PMA but then I'd have to install a pamco or points system and ditch the billet can covers I made.....in the end more money to spend hahaha!
3. It is very difficult to make boost pressure when the blow off valve is adjusted too loosely. The turbo was spooling but by the time I noticed the bov was adjusted incorrectly the battery died.I have a short video on my phone and I will try to upload it soon.

 

[plattey]

Also ordered rods from mikes plus a couple seals and gaskets. Also talked with the Honorable Hugh from Hugh's Handbuilt concerning the crank and will hopefully be sending a spare crank with the race rods out to him soon.

 

[cowboy3669]

the turbo won't make boost unless under a load.won't boost up just winging the throttle.

 

[plattey]

.....think a road test will be necessary soon in that case cowboy

 

[Johnt3]

plattey, You got some balls man. Sounds like your getting this figured out.Good luck with the road test.

 

[member3480]

LOVE IT. I have done about 25 Turbo bikes and just finished up a Busa turbo. I have one of those little turbos sitting on the side here and want to do a XS650 but have not got to it yet. The only thing i can tell you with the turbo you got is it may be a little bigger than you need and boost will be low. If not you may just blow the boots off the carbs but i don't see anything else that you did won't work once you work out the bugs.I have talked this over with Jon from Monstercraftsman a while back and they did one that worked fine and spooled up. Crank and rods should hold up for street use with low boost.LOOKS COOL.get a video up.
The other guy with the KZ done many and it will take a big turbo easy. My last KZ pulled 28 pounds of boost with big turbo and was only 1200 motor low compression pistons and i was clocked on the AC Expressway at 193mph. Took cop 7 miles to get me only because i had to stop for toll HAHA.
Guys Turbos are fun but big difference from street use and Drag use.
Good luck with your build VIDEO!!!!PLEASE