Garrett T25 Turbo Build

[plattey]

Sorry for replying so late. I just moved to Osceola WI and was busy moving in and such.
Cowboy, thank you very much for the reply. It's amazing that the stock rods and pistons have held up as well as they have for this long now! As far as the cam goes, if there's a cam out there that has less valve overlap, that would give the intake charge less of an opportunity to short circuit and exit out the exhaust. More lift would be beneficial though?

alwaysmonday, that's pretty sweet! Living the dream of Burt Munro that's for sure! I like the way the 350f engine looks
A friend of mine from college gave me this book to use during this build and I've been referencing it.
http://xedomibe88.blog.com/2012/11/...-performance-street-turbocharger-systems-pdf/

I don't have garage access at my new apartment so.........I have a new roommate! Latest update. I've decided to go with a blow through setup with two vm34's. Thought of using a blow through with a single vm38 but I've got the 34's already, so why not.

 

[plattey]

Took some time to make an intake manifold. The manifold is made from 2.5" exhaust pipe. I used a holesaw to cut the holes in the intake manifold and tin snips and hand files to make the runners. The bov pipe that I'm gonna order is 2.5" diameter and the silicone connectors from the bov pipe to the intake manifold are 2.5" diameter. The intake runners are 2.25" diameter to match the intake bell for the vm34's. For now looking for someone or a shop to weld the intake manifold together and also cleaning up the wiring underneath the seat to make room for an auxiliary oil pump, fuel pump, and fuel pressure regulator.

 

[plattey]

Finished cleaning up the wiring last night. The pigtails coming from the RR unit and the TCI box had to be shortened a bit. Trying to fit most of the wiring and components under the seat was like trying to fit 10lbs of shit in a 5lb bag

 

[Focusinprogress]

I missed the part about whether you plan to go blow-through or draw-through carb/fuel-injection.... Do you plan to have the intake manifold coated with something to prevent rust? If it's going to have atomized air&fuel flying through it, I'd be concerned with the fuel being a catalyst for that mild steel to get rusty quickly.....come to think of it, if having it coated inside and out, the coating will probably have to be fuel-resistant

 

[plattey]

It's gonna be a blow through setup. Probably paint the manifold after it's welded. I'm not sure if I'll coat the inside though because I don't want the intake manifold to retain heat. Aluminum manifolds are already installed between the carbs and head too. Wise Guys Customs ceramic coat their manifolds but they have the carb at the intake since fuel and air go through their manifold.
Last night I modified the oil return line from the turbo center housing so it would direct the return line more towards the bottom of the engine. The fitting is a 1" pex brass fitting and the original return line from the T25 just slips inside the pex fitting. So I used a 3/8" ratchet extension to expand the T25 line fitting to make it an interference fit. Once I have the supplies, gonna try my hand at brazing and braze the two pieces together. The starter removal mod (somewhere on this forum) allows you to use the front snout of the starter motor as a block-off plate. I tapped the snout for a pipe fitting when I did the starter removal mod (see pic). The oil return line for the turbo will be going there once I get a barbed fitting placed.
Ordered the bov pipe today. Hopefully have it in next week.
http://www.ebay.com/itm/TYPE-S-RS-T...Parts_Accessories&hash=item2eb9fcdd54&vxp=mtr

 

[plattey]

I really wish that I could say I did the welding on the intake manifold and the oil return flange but I'd be telling a huge lie A co-worker of mine that's big into the old kz's has a mig and tig welders in his shop and helped me out majorly. He tried brazing the pex fitting onto the steel flange but the steel was so thick that by the time the steel would take braze, the pex fitting would overheat and melt away. So he suggested that we get a 1/2'' npt coupling and tig that on instead. Worked beautifully.
Ordered the bov pipe and silicone hose connectors last friday and parts should be arriving this thursday.

 

[plattey]

Some pictures of the oil return system for the turbo. The oil return hose will have some braided sleeve to protect it from the road and debris.
Going to have to find a good place to mount a large oil cooler. Was thinking of mounting it parallel with the front wheel, just above the alt cover in front of the engine and building a scoop to direct air through the cooler. Would like to mount the cooler so that it doesn't impede air flow to the cylinder head and jugs. Could also have multiple smaller coolers as well. Suggestions?

 

[Yamaha_chop]

Don't have any suggestions, but I really love the turbo drain return location. I retained the electric start on mine so I couldn't do that, but it's a great idea!

 

[scabber]

Nice work platty. The bike should be a hoot to ride once the turbo starts boosting.

 

[itrguy]

Diggin it!

 

[JP50515]

If this works, What you do is start selling a kit for this ha. bet you'd make some decent money

 

[wallywheels]

After seeing this I am 99% sure I need this on my bike I have nothing behind my engine so plenty of room kick start only. A question though. Is there any advantage or disadvantage to running the "carb or carbs" before or after the turbo.

 

[plattey]

Thanks everybody for the compliments. Wallywheels:
Draw through (carb at turbo inlet)
Advantages: 1. No need to run a blow off valve
2. No need to run a pressurized fuel system

Disadvantages: 1. Fuel can drop out of the air flow stream more easily
2. Poor throttle response
3. Under high vacuum (for instance, going from wot to no throttle) oil can get drawn past the compressor oil seal and end up in your intake tract. Eventually hurts the turbo.

Blow through (carbs after turbo)
Advantages: 1. Better throttle response (carbs closer to the cyl head)
2. Solves the draw through setup disadvantages

Disadvantages: 1. Need to run a pressurized fuel system and pressurize the carb(s) in the case of the vm's need to block off the float bowl overflows. From the book I reference to, it says that fuel system should be about 4 psi above boost psi.
2. Need to run a blow off valve

Hope this helps.

Another thing, I'm going to have to remove my kickstarter everytime that I get the engine running. The intake tract will be in the way of the kickstarter returning. I talked to a friend of mine that does ahrma racing with the xs and he said that one of the racers actually removes the "E" clip that holds the kicker in place so he can slide the kickstarter arm on and off as he needs and it doesn't fall off when he kickstarts the engine.....we'll have to see if this works well and wear shinguards during initial testing

 

[wallywheels]

I am running a Mikuni 36mm roundslide single carb setup is it possible to block overflow lines on this carb to create a fuel pressure and if not how do I get pressure with a pump? I am going to run a post turbo carb setup? Thanks for the help

 

[wallywheels]

If I went with a fuel pump would something like this
work? http://www.ebay.com/itm/Universal-1...Parts_Accessories&hash=item5d39d87fcc&vxp=mtr

 

[plattey]

Wally, even if you block the overflow lines on that vm, the float bowl vent is connected to the intake bell. If you run a blow through design (carb after turbo compressor outlet), you will have to run a fuel pump. Otherwise the boost pressure will either prevent fuel from flowing into the float bowl or escape past the needle and seat and past the gas tank cap (if it doesn't cause other havoc). Also, a setup like that without a fuel pump would set the bike up for a lean condition everytime it would hit boost. If you plan on running a blow through setup, it's a very good idea to run a fuel pump that will deliver at least 4 psi (taken from the book i referenced earlier in this thread) over your planned boost pressure. The wastegate on the t25 currently limits boost to 10 psi, but I may put a manual boost controller when the engine's ready to handle more. So I plan on running a 20psi max pressure fuel pump and a good quality fuel pressure regulator. Here are the parts that I'm planning on using once the funds come around.

Fuel pressure regulator:http://www.summitracing.com/parts/maa-4307m/overview/
Fuel pump:http://www.summitracing.com/parts/dfp-fd0002/media/images

I hope this helps.

 

[wallywheels]

Thank you very much for the reply I have done some research and that is what I am going with I am also adding a boost line from the boost intake side into the top of the carb to compensate for WOT when boost happens and also into the bowl overflow line to equalize carb pressures. I also ordered a 1.5 needle set for my vm36 mikuni instead of the 3.5 so that the fuel pressure will not keep the float open.
Also to add those same fuel pump and boost compensated pressure regulator are almost exactly what I had ordered just a 30 GPH fuel pump!!!

 

[plattey]

It will be interesting to see how the vm's handle having more than ambient pressure run through them. If they don't like it, it's back to the drawing board with either a cv type or go down the efi road like Yamaha Chop

 

[plattey]

Parts!!! Parts came in friday and monday. The silicone elbow and adapter hoses, the bov pipe, and the oil supply line for the T25. An interesting note though. The banjo bolt for the oil supply line that threads into the turbo has a very small hole (eyeballed at about 3/32") that probably chokes the oil flow to a set mass flow of oil. So it may not be completely necessary to run a separate oil pump to feed the turbo. If the xs650 oil pump can supply enough oil to the turbo without starving the engine or the turbo, it'd be great. Gonna look more into this. But for now gonna stick with the plan of using the turbo scavenge pump to supply the turbo with oil. I drilled into the right side intake manifold and jb welded a barb for the bov and fuel pressure regulator intake pressure tap. Milestone 2 met with the completion of the intake tract.

 

[Focusinprogress]

I notice that your turbo is build for both oil cooling and water cooling.....are you going to just block-off the watercooling ports or run a closed loop system to a cooler and fan?