Turbo head design/thought... and other turbo doo discusion.

[Wheel House Motorsports]

So im currently starting to think about and get ready to build a fun little toy this summer, just working out some details, and figuring some things out on the project before I dig in come june. goal of the sled is to be fun to ride, super light, and have more then enough power to move a person around. ITs going to be a prototype chromoly tube chassis, so its gonna be stupid light, just always want more power to, and make riding it up high still crazy fun.

motor is a 01 doo 700 top end on a 05 600 bottom. basically a lower comp version of the 600 ho.

#1- the stock doo head design just seams really weird and backwards of the design one would want? not really wanting to mess with that part as Im not interested in making an entirely new head, or domes, just modding stock ones. for a cheap, and affective detonation prevention would it be productive to mill the outer ring of the head out 1/16"? by outer ring I mean where the edges of the dome are closest to the piston around the edges? this seems like it would barely drop compression but from what I have read would help deal with detonation. I don't mind a slightly softer bottom end as the sled is gonna be LIGHT, and not need huge power. My goal is to make the motor safe on 6# at 5000 and 8# at say 7k+ with pump with a dash of race gas for saftey.


#2- just looking for thoughts on the properly sized garrett for this application, a 700 maybe cranked to 12# MAYBE ONE TIME ever... most living 6-8#... 2860 seems like a little overkill for this sized motor at this boost levels. I know I will want to turn it up, but its not my primary sled, it will be riden mostly by a 130# rider, if shes nice to me ,

#3- Because its going to be custom, its getting an oil injection deleteand trying to put the turbo sorta like the CPI setups, intake side in the back, Working on an idea of taking the top section of the tunnel under the jackshaft area and turning it into a small tunnel cooler/charge tube, it would be the same length as a normal one, just be bombared with snow instead of just a hose in the engine compartment which is gonna get warmer... seems like a few degrees would be dropped by a icy cold charge tube, and therefore safer on pump and more power to boot.

for those who have build there own setups, im looking to kind of bounce ideas of people, think/learn. I have already learned a lot about turbo'ing sleds from the yamadoo thing, just looking to learn as much about boosted 2 strokes before I dig into this project.

 

[turbo800]

If it was me I wouldn't cut more than .015" thou out of the squish band. The 01 was already a low comp. version of about 12:1. If its a summit head I would take that amount out of the squish, if its a mxz head I would leave it alone.

As for the turbo, for that amount of boost, its gonna be hard to beat the cost of a Mitsu. Evo, unless your sold on a ball bearing unit, nothing against Garrett's they build great turbos.

 

[Wheel House Motorsports]

no, I love the mitsu's... thats what I got on my yamadoo, but my only gripe is oil pressure.. methinks a 16g would be a pretty darn good sized turbo, they got pretty small exhaust sides.. combined with the decent sized compressor, should spool fast, and the cost is hard to beat.

I know somebody posted something about a mechanical pump that runs off the oil injection, but can seem to find it now. Im actually not sure what the head was off of, summit or MXZ.. when i throw a fresh top end in it I will do a compression test for fun. after reading the guy badass1000 running 7psi on pump on his XP at 7k+ im thinking the older less agressive timing and lower comp i think my goals might be totally safe if I dont jet it to lean!

 

[canucklehead]

Working on an idea of taking the top section of the tunnel under the jackshaft area and turning it into a small tunnel cooler/charge tube, it would be the same length as a normal one, just be bombared with snow instead of just a hose in the engine compartment which is gonna get warmer... seems like a few degrees would be dropped by a icy cold charge tube, and therefore safer on pump and more power to boot.

I have been thinking exactly the same thing with the charge tube. Did you see the ones with the extruded outer edges? Since your building from scratch you should definitely try to incorporate it.

I would measure the squish and comp before doing anything to the head you may not need to do anything.

 

[turbo800]

Sounds like a good plan. Throw your new top end on, put a piece of plumbing solder in the hole(stuff w/o flux), make sure its against the cylinder wall and cycle the piston past TDC. Then you can check the squish clearance. I would recommend about .075~.077" squish, good for 12psi and 100 octane @ 8000'

I was the one that posted about the mechanical pumps, its an alternative to electric.

 

[Wheel House Motorsports]

I have been thinking exactly the same thing with the charge tube. Did you see the ones with the extruded outer edges? Since your building from scratch you should definitely try to incorporate it.

I would measure the squish and comp before doing anything to the head you may not need to do anything.

HMM... i can check squish easy like now.. as far as the pump, could you PM me a price figure.. Really like that idea, as I dont like putting that much electrical stuff into a sled with not much to start. and mechanical is way less likely to fail on me, just something else to not worry about.

as for the charge tube.. I would basically fab up a cooler setup just like the stock tunnel coolers. thin with lots of surface area.. nothing to crazy, just help drop some heat seems like it coulndt hurt at all.

 

[jskattum606]

Sounds like a heck of a good project. Im in haha. I hope this thing becomes a reality soon. Cant wait to get my 800 done at the same time. Thanks for all of the great info everyone.

 

[Wheel House Motorsports]

so if you have an t-800... then i guess we shall just bump up the boost on the 7 to keep up??

as for fueling... what are people doing for setups relative to stock.. I know each custom setup has to be dialed per sled, BUT, with the boost referenced carbs are people seeing larger then stock jetting, or close to all the way across.

another thought, DPM, what is involved with getting rid of it?

 

[badass1000]

I have ben runing 7psi at 6000' and up. I am ocasionally at 5200', but it is across the lake and on the flats. Don't really hold it pinned for a long time below 6000'.
The last few rides I have ben detonationg on the pump 91 non ethanol I have ben runing all winter. I buy from the same gas station every time. Luckily when it started I had the 2.5 spare full of 110 sunoco as i was going to turn the boost up that day. I don't know if the gas station got some bad gas or has changed their fuel. Only changes I have made that I can think of before this started hapening is I wraped my pipe with header wrap and their was a crack on the inside of my pipe that got welded. Crack on the inside of the pipe getting welded should have ben something that would help prevent detonation. Sled was making 7psi previously. All a leak would do is overspool the turbo and increase charge temps. Higher charge temps = more pron to detonation.
My 08 had the earlier programing in the ecu that the sled had to be taken to dealer to reset the ecu. Had it updated so check engine light from knock sensor resets when sled is turned off. No signs of detonation on the plugs and I just pulled the head off and no signs of detonation on the pistons. Sled did not run as good and power droped off when the detonation sensor was going off. Not positive if droped power was from a over sensitive knock sensor pulling timeing or from too low of octane fuel.

I am runing 2psi at idle with the regulator hooked up to vacume source. regulator hooked up to the line going to the bov. with line to regulator disconected ( no vacume) it is 3psi at a idle. I did this to keep fuel presure down at idle and keep it from loading up. it was loading up if idleing for a long time and then would sputter for a little bit when you pin it. regulator is 1:1.
i droped from stock 480's to 370's on my xp.
on the dpm you have to leave it pluged in so it does not throw a check engine light, but disconnect and block all vacume/boost lines going to it from the carbs. I put caps on all outlets/inlets of the dpm just to keep stuff from getting in it incase I ever hook it back up.

 

[Wheel House Motorsports]

sweat. thanks for the info on the dpm.. I was curous how that would work without going to a race style computer setup. as far as the head, do you know what the stock compression of a 800r motor is?? I know those poor old 700's dont have a whole lot to speak of.. might drop a little compression for saftey, but im thinking you could easily make good power on pump+ a little bit of mix.

thats crazy low on the jetting.. oh well, I know how it goes, on my rx1 setup im a bit below stock on mine! stock for elevation is 130's.. im runing 120's and could use to drop to 115's!!

Fuel pressure sounds about the same as I did, if you referenced only boost not the vaccum/boost then I could get a crazy fat idle. but right now its set at 2/3# at idle then as soon as you tap on it the thing goes right up quick like with boost.

mmmmmmmmmmm cant wait for a light boosted sled.

 

[canucklehead]

Check the squish and the cranking comp. You should have at least 70 thou squish. Stock 800R at 3k was 129 on my gauge. The dpm compensates about 10 jet sizes... I used to run 480's with a few mods and now 380's with no dpm and the turbo but also powerjets.

 

[Wheel House Motorsports]

alright.. so basically drop 100.. then work up with the powervalves as a start?? right now im just trying to compile all of the info possible I can in one place while people are out playing on there sleds.. this way they know exactly what they did/are doing.

I think the 600's run the same carbs as the 8's if im not mistaken.. so boosting them would be the same game for what most of yall are used to?

as far as cranking compression, I think the motor would run about any boost on pump gas right now.. the top end on the thing is kinda tired.. needs new pistons/rings. but ill check the squish before I play with it and totally take the sled apart this spring.

also excited after reading Gus's posts about the 600ho reeds being ideal for boosting.. I have 2 sets of delaminated ones with perfect petals.. so got plenty of extras of those.. nice things to have laying around!!

for the rave valves.. these ones arent all fancy like the new ones.. how would I go about dealing with them under boost? seems like the diaphragm would just blow apart?