Anyone tried a rear mount?

mestona

Registered
The trash-trunk mod made me think, there is a lot of room in the busa tail section. Has anyone tried making the trunk more shallow rather than deeper and putting the turbo under the tail? I have seen it done on other bikes, most recently in SSB magazine, but has it been done on the busa? It seems like you'd get to keep the oil cooler, have more room for an intercooler and have room for a bigger turbo?
 
The further the turbo is thought, the more lag you'd get.. :down:
 
The further the turbo is thought, the more lag you'd get.. :down:

This^^

It would not effect the oil temp, as it's still passing through the turbo. It make the engine run a little cooler because the radiator is not right next to the turbo.

I'm sure it would work fine, but I wouldn't expect any additional gains and your a$$ getting hot.
 
They actually run cooler as the exhaust gases have cooled way down if not right off the header. There is a company that makes rear mounted turbos for cars, and the turbos are tuned differently than ones that run right off the header as they can not take advantage of the higher speed hot gases coming right out of the header. They do provide a cooler charge however as there are advantages and disadvantages to this type of boosting.
check out ststurbo.com/ for more info (I am in no way associated with this site, just providing info)
 
Yeah you would have to wear thermal protectant undies :laugh: It would burn a hole in your :moon: and your bank account:rofl:
 
Brings back memories of the shandies (sandies???) rear mount bike turbos, don't think they ever too off
but a google search trying to find a link shows several home made kits
Think i will stick to my front mount ;)
 
They actually run cooler as the exhaust gases have cooled way down if not right off the header. There is a company that makes rear mounted turbos for cars, and the turbos are tuned differently than ones that run right off the header as they can not take advantage of the higher speed hot gases coming right out of the header. They do provide a cooler charge however as there are advantages and disadvantages to this type of boosting.
check out ststurbo.com/ for more info (I am in no way associated with this site, just providing info)

Cooler charge??? Not sure why you would think that, the compressor cover does not see heat from the turbine side, and pushing the boost pressure through an extra 6 feet of charge tubing will add heat to the intake charge,

Richard
 
Cooler charge??? Not sure why you would think that, the compressor cover does not see heat from the turbine side, and pushing the boost pressure through an extra 6 feet of charge tubing will add heat to the intake charge,

Richard
Have you ever seen a turbo off the header, under full boost, at high rpm (I know you have, just stating the obvious). They glow red like molten lava. Yes that does seem to me like that would heat the charge. No they dont glow when the turbo is 4+ feet of tubing down the exhaust line. My turbo happens to be conventional, right off the header, and believe they are the way to go (intercooled of course). However, I can see why they claim on their website that the have the lowest intake air temps in the industry. It just seems logical to me, that if the turbo is not glowing, that the temps would be cooler. Heck, you could put your hand over the end of an exhaust pipe and hold it there until the engine stalls and not burn your hands, but try doing that right off the header and you would be taking a trip to the emergency room. Im not here to argue about it, take it up with the people that make the claims on the ststurbo website. I am just making an observation, and it sounds plausible and they do work, however I do doubt they could be as efficient as a conventional intercooled system. Pushing the charge through the 6 feet of intake tube could theoretically act as an intercooler (not as efficient as a finned intercooler though), as isnt that what your doing when you intercool, as in push the charge through a type of radiator that adds surface area in feet from the turbo to the plenum and the radiator runs off ambient airtemp, as would the 6 feet of pipe that is not connected to the turbo or plenum other than by rubber hoses. Like I said though, I have not done side by side tests, and I am no expert like you are, it just seems logical to me that the farther away from the heat source, the cooler it would run, however I would expect the pressures to be lower.
 
They actually run cooler as the exhaust gases have cooled way down if not right off the header. There is a company that makes rear mounted turbos for cars, and the turbos are tuned differently than ones that run right off the header as they can not take advantage of the higher speed hot gases coming right out of the header. They do provide a cooler charge however as there are advantages and disadvantages to this type of boosting.
check out ststurbo.com/ for more info (I am in no way associated with this site, just providing info)


As someone who does tuning in the v8 car world (lsx motors specifically using HPTuners) sts turbo systems are absolute garbage... Having tuned numerous turbo setups from mild to wild, rear mount systems are consistently a disapointment...


the rear mount turbo system was a cute idea that worked terribly in the automotive world and appealed to people look for cheap FI options.... they suffer from tons of lag, and consistently make significantly less power than a correctly sized front mount...

I have seen them on motorcycles, and they look kinda cool (primarily because they usually run no filter for effect)... and i have always wondered if they might work a little better than in the car world... a lot less distance for exhaust gases to travel... but then again, it doesnt get much shorter than being bolted directly to the header.....



IMHO, not worth the pain and effort...
 
As someone who does tuning in the v8 car world (lsx motors specifically using HPTuners) sts turbo systems are absolute garbage... Having tuned numerous turbo setups from mild to wild, rear mount systems are consistently a disapointment...
constant problems with those STS kits. absolute garbage is right. I personally know of two ppl that had their rear mount kits. one on an Fbody and the other on a dodge magnum. garbage!

trying to reinvent the wheel is rarely a good idea. if rear mount systems were that good you would see them on more cars. you dont. bikes would be no different. and where would one put all the other electronics such as boost controler, data logger, co2, microtech box, etc....? its not like there is a whole hellova a lotta room on a bike.
 
Im convinced, like you said, sounds like a cute Idea, but I have never actually seen/use one in person. Now I know, and knowing is half the battle, haha. Thats probably why they can claim they run cooler, cuz they aint doing anything to make heat. Thank You for showing me the light :bowdown:
 
We have a guy in maple ridge here that put his turbo on his gold wing behind the license plate.

Ended up modding his tank to have the cold side tube go through it to the motor.

Pretty wild. He has over 100000kms on the setup. Trailers two kayaks behind him too.

It's a route I'm considering when building my turbo setup for the busa.
 
Ive burnt a tank of gas thru my friends GSX1400 turbo (mounted under the seat) with no
hot seat problems, it is sort of wrapped. Its a real sleeper as the only thing that might give things away
is the side mounted pod filter.
Bike runs like a normal 1400 till about 4200rpm when you notice a surge, by 5000 its all go till redline :)
Its just over doubleing orig modest hp (106) with stronger rods and stock everything else, PC3 and custom
map by him using a friends dyno.

A GSX1400 is an air cooled 1402cc in line 4 original own engine - not just a bigger bandit mill.
 
One thing to remember is that a turbocharger works on exhaust gas volumes and velocity. The further the turbocharger is from the motor, the exhaust cools (slightly), meaning slightly less volume, which would delay boost a bit. I've ran a rear mount turbo on a sled and the delay kinda sucked, but was great fun once it hits. That's one reason why Mercedes has started building integral turbines into their motors from factory....most efficient place for them. If temps due to the snail being right in front of the motor and behind the rad is an issue, could it not just be wrapped??
 
Not a busa , but a k6 thou,. Rear mount and for the street on STD wheelbase it's fast enough....

IMG_20150925_145959.jpg
 
That is way better than hiding it bahind the radiator and fairings. Plus that way you don't have to worry about buying a backrest.
 
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