Homebuilt 2015 YZ450f Turbo Kit for Timbersled for under 1500 bucks!!

Hello all,

I decided to go turbo this year on my yz450 but didn't want to buy the KMS Turbo kit for 5k so, as a mechanical engineer, I decided to make my own kit and pocket a lot of savings. This thread will be my progress and its thouroughness will depend on the interest that I get. I feel that there are a lot of guys that would like to turbo their bikes but 5k is a very steep price. I have bought all the parts that I need and am sitting at just under 1500 bucks!!! There is a bit of fabrication that I have had to do...but it was worth it to save the coin.

So far I have done the calculations for which turbo to use, verified that my turbo choice is correct, ordered a replica turbo, ordered all my parts, fabbed up my exhaust supply, fabbed up my mount, and made my own prefilter to match the one sold by Boondocker.

So far the parts list is as follows:
GT2252 Replica turbo-250
GT2252 Exhaust flange - 70
Stainless 90 degree 1D bend 2.5"OD pipe - 50
Stainless 2.5" to 2" reducer - 25
Dynojet Power Commander 5 -320
Dynojet Autotune Unit - 250
4x2" 90 degree silicone elbows - 30
4x2" 45 degree silicone elbows - 30
6' x 2" straight silicone 3 ply hose - 80
12 stainless steel 2" silicone joiners - 95
1 stainless steel 3" silicone joiner - 8
2 3/8" to 3" 90 degree silicone adapter - 12
25 stainless steel t bolt clamps - 65
Boost gauge - 25
Outerwear 6x3" cone prefilter - 22
36" 4an to 4an stainless brake line - 21
Turbo oil drain flange with 5/8" barb - 18
Aluminum an4 to M10x1.5 fitting - 13
m10x1 to 4an Turbo Banjo Bolt Kit with 1.5mm restrictor - 20
5/8" barb to 3/8"NPT 45 degree fitting - 7
5/8" heater hose x 5ft - 30
2' x 1' x .25" A36 Steel Plate 15
2' x 1' x .125" A36 Steel Plate 15
1.75" x 12" exhaust pipe - 10
Assorted Hardware - 12

Total so far is 1493!!

I understand that my setup is not the lightest turbo kit on the market..... but I am going for durability. I had a mishap out west last year that left me 7 miles deep in the mountains with a 300 pound anchor and I don't want a repeat. If it lasts the winter then I will start to pull weight out of it.

I went with silicone as my intake charge piping because if you lay the bike into a tree or something then your charge pipe doesn't get mangled and pinched. It will spring back when you pull it off the tree.

I will post more info and pictures if people show an interest. Let me know what you guys think and I will throw some more stuff up on the site.

Thanks,
Stevo

scottbilt95 said:

-turbo location?
-boost level(s)?
-additional fuel delivery?

if a person was a decent fabricator, and doesn't get greedy on boost levels, should be do-able. not sure about lag depending on turbo location.

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The 15 YZ's have the exhaust coming out the back of the engine so my turbo is a rear mount. It mounts to the Timbersled right about where the brake caliper mounts. I have decided to weld straight to the Timbersled rather than trying to weld a tab to the Timbersled and then bolting to the mount. Since my mount is parallel to the exhaust I will be able to unbolt the turbo and remove my exhaust when spring comes and return to my dirt setup.

I am planning on starting with 10-15psi of boost. At my calculations that should make me about 80-90hp at sea level. That is more than enough for right now. The main goal of this is to make a reliable setup that I can use to gain a decent amount of power and not have to worry about power loss at altitude.

Extra fuel delivery will be accomplished by the Power Commander with the Autotune unit. It uses an O2 sensor in the exhaust and will automatically tune (to an extent) the fuel map to get the bike to optimal A/F ratio. It has limits of course. If the A/F ratio falls outside of a certain range it doesn't know what to do with it so I will have to get it close by hand but the PowerCommander software is nice and easy to use.

I am basically aiming to get a mix between the Boondocker setup, and the KMS setup. The KMS jams the turbo way forward and I don't think that is possible with the timbersled because of the strut rod. I have only seen the kit installed on a YZ with a Yeti. The boondocker setup is mounted way back and high. I want to make mine as high and forward as possible to reduce the lag as much as possible.

Seems that any way you do it you will have a long run to somewhere... If you have a front exhaust and mount in the back you will have a long exhaust run but short intake run. If you mount in the front, you will have a short exhaust but long intake run. With mine I will have a short exhaust run but a long intake run.

Here are some pictures of what I have so far.

I traced the flange for the exhaust off the stock gasket and cut it out using a plasma cutter to get me close and then used a flap disk to get it closer. I used a hole saw to cut the hole for the exhaust. Since I don't have a mandrel bender I just used bias cuts to get around the strut rod and angle up to the turbo. Once I got everything tacked up and verified the correct location I made my rear flange out of .25" plate. Probably could have used .125... but it is stronger for it. Then I final welded everything. I then cut a hole for the O2 sensor bung and welded that in. All welds were done with a Tig welder.

Next I cut a plate for my mount. It needed a 2.75" hole in it for the exhaust outlet so I cut that out with the plasma cutter. I laid the turbo exhaust flange onto the plate and lined up where I wanted the mounting holes to be and then spot welded the flange to the plate and then drilled the mounting holes out. For my placement I would need a bend and an angled/rounded cut to meet the tubing on the timbersled so I mocked it up with cardboard and traced it onto the plate and then made the cut and bend. You will see a picture with it in place but not welded. That is when I ran out of time and had to head home. I am doing the fabrication in my dad's workshop in Detroit and I live in Wisconsin and just drive over on weekends so time is limited.

Oh, and for the prefilter, I just bought the cone prefilter and then bought the 90 to fit to the turbo. I also bought a 3" silicone joiner. I took some larger diameter tig welding rod and bent them to look like what they use in a boondocker prefilter setup, basically a U and then once the silicone joiner is inserted I stuck the legs of the 4 wire pieces in between the silicone and the joiner which is a very tight fit by the time you are trying to get the 4th one in. My plan is to pull the prefilter over it and then put a clamp over the prefilter, silicone, and all the wires to hold it all together. Should be great.

Hope you guys enjoy so far. Hit me with questions and I will keep up with updates.

Here are a couple more Pics including the mount.

One more thing I have learned is that my mount will result in not having to trim any plastics like I thought I would. I plan to not run a rear fender though, as you would have to basically cut it a lot so that it wouldn't hit. Do you guys see any reason why I couldn't run without a seat?

4bangrboost said:

At 10-15psi on stock compression you need to run some better fuel (don't forget these things are 12.5:1 compression) both stock and forged pistons will start to crack at that boost. I run a 50/50 mix of 91 pump fuel and 110 race fuel in all my turbo bikes. Also I don't see the PCV with auto tune working for turbo unit. You need the efi to be boost referencing. Maybe you can add Dynojet's PTI system to your PCV. I doubt that the stock injector will support 15psi either, I run a secondary (staged) injector on my YZ.

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My dad is a pilot so I was planning to run 100LL or AVGAS almost straight without much dilution to eliminate any kind of fuel problem. As for the Autotune, I chose this because that is what comes in the KMS turbo kit. The boost ups the fuel usage at certain throttle points but it should be rather consistent, meaning that, for example, once the autotune unit finds what amount of fuel to add at 5000rmp at 60percent throttle it shouldn't wander from that value because the boost created at those conditions shouldn't really change because the inputs haven't changed. I have also spoken with Dynojet about this and they have told me that it will work but I have to get the A/F values into the range of the O2 sensor before it will start to tune it automatically. It is a high bandwidth O2 sensor so it should be able to correct quick enough anyway even if the conditions did change.

This is my conjecture at least....only time and experience will tell, but it seems that a lot of turbo kits contain an autotune unit.

[/QUOTE] both stock and forged pistons will start to crack at that boost. I doubt that the stock injector will support 15psi either, I run a secondary (staged) injector on my YZ.[/QUOTE]

What kind of HP are you getting with 15psi? I may have my boost number a little high. I know that I will need to add 4psi of boost when I go up into the mountains to account for the altitude change but I am curious what kind of HP you are seeing with 15psi. Also, do you mean that if I don't run better fuel the pistons will crack, or at 15psi the pistons start to crack no matter what?

Well you guys have given me something to consider... I didn't know that the KMS kit came with a second injector... That throws a big wrench into play... do you guys know of an off the shelf way to add said second injector? Could I just add a secondary injector kit from a yz250 into the charge pipe? I have only been able to find a secondary injector kit for the 250. It also sounds like I need to either buy a 0-5v boost gauge and plug it into the PCV and add Boost tables to my Map or get Dynojets PTI module...? it is starting to seem like I want to stay at 7 psi at sea level and 10 psi at altitude to be reliable...? So glad that I posted this, without your input I would have blown this thing up for sure. Would anyone be willing to send me your fuel map for my PCV?

Well I have spoken with Dynojet about adding a PTI module for my bike and they have told me they don't sell one. I asked if they sold a secondary injection module that would work with my bike......and he said that they don't. My next step is to contact KMS and see if they will sell me their second injector module, second injector, and map... does anyone else have any input? From what I have read about secondary injector kits, they just Y the fuel line and Y the electrical and then just run an adjusted map to account for the fuel coming from two sources. I am wondering if I couldn't just buy a second YZ450 injector and put it in the charge pipe and then Y the electrical and fuel leads and then reduce the fuel in the map to about half. The autotune unit would then bring the fuel values to match the desired A/F ratio and then I could start tuning using a boost/RPM table. Does this sound legit?

4bangrboost said:

Did you ask if it was possible to just add a MAP sensor to your PCV and run a boost table? You just might be limited on how much boost the single injector will support.

Its to bad the PTI isn't compatable, I was hoping to use a complete dynojet system on my next build, instead of the dyno/kms hybrid. There must be some other efi options out there somewhere..

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He did say that I would fully be able to reference any 0-5V MAP sensor and plug it into the PCV and get the Pressure vs RPM tables into the fuel Map. That will be what I probably do.

SuperchargedWS6 said:

http://www.powercommander.com/power...e/powercommander_v_secondary_fuel_module.aspx

this, with a pcv and a map sensor tied to the pcv is all you need.

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They don't make that unit for my bike and they don't offer a universal model. I asked Dynojet if they made one that would work for my bike and they said that they don't offer one for my bike to support adding a second injector. Do you know something that I don't cuz that would be a much easier setup haha. I am contemplating adding a second yamaha injector and just combining it to the original injector and then modifying the map to run lower fuel levels...