Jnimbostratus Street Fighter Project

[jnimbostratus]

Tb location is going to come down to real estate  once I go to the local salvage yard and pick one out and decide where the most efficient location is. I took the carbs to the salvage yard to do some comparing and it looks like a Honda b16 fuel rail will put the injectors center of each intake runner

[skymasteres]

You know, I've been playing around with this idea in my head forever. But with your level of skill and ability to "make it work" I think I'll share. (Especially since I'll probably never ever get to it)

Why hasn't anyone setting up a turbo on an FJ turned the cylinder head around?  I mean, the spark plug orientation doesn't change. The cams are semetric so all you have to do is turn them over. The only thing I can see being a slight issue is the oil galley passage coming up from the cylinder block. But I think it'd be pretty easy to solve that one. (A little drilling and plugging and you should be good to go)

Plus it would make for a MUCH cleaner turbo install. I mean, you get all of the advantages of heat retention putting the turbo under the seat close to the exhaust. (You might have to be creative with getting the right primary length for the exhaust though. You still need some length for good scavenging and timing)

It makes the intake side a lot easier too since you might be able to squeeze the compressed air tube over the valve cover and go straight to the intercooler in the front. You'd definitely want to go fuel injection though.

It also means you're going back and forth a lot less with the tubing which saves weight,  reduces your losses, tightens up your boost response, and makes more power. (That and with less tubing you right actually be able to make it a "stealth" instalation. Just about tuck it under the original body work. (The only really weird part would be dealing with the throttle body and intercooler bits)

I don't know. I've just been playing around with the idea for a while. I like it a lot. (Though it's only been in my head) I still am not good enough on the bike to use all the power it has naturally aspirated...

[Pat Conlon]

There is a reason the exhaust valves are in front. Those exhaust valves need air flow, so the exhaust valves and manifold under the seat....Hmmmm
What could go wrong?

The turbo mounted low in front is superior for cooling and spool up.

[skymasteres]

There is a reason the exhaust valves are in front. Those exhaust valves need air flow, so the exhaust valves and manifold under the seat....Hmmmm
What could go wrong?

The turbo mounted low in front is superior for cooling and spool up.

Geeze Pat, I would have thought you'd put at least a little more thought into it before poo pooing the idea.

The heat isn't the main issue. Though,  like any engineering process,  it's all about balancing the imprtance of the design objectives. The low and tight, mounted off the front, turbo arrangement is ideal with minimal complications. Only issues that I thought of when considering this were the oil return line, wheel clearence, and exposure to the elements. The main advantages are the free access to frontal cooling air and the lack of exhaust tubing surface area to loose heat from.

The heat issue with the heads is secondary to the packaging of the exhaust system and the length of the primary tubes. That and the typical induction system, airbox and carbs, won't fit in that space to the front of the engine.  They can, and already do, duct air for supplemental cooling. If you look at the stock exhaust header collars you'll notice that they're finned aluminum to provide more surface area for heat exchange.  As long as you can get ambient air to it,  AND get it exhausted,  you're good. 

The main issue is proper ducting. As a general rule,  you want 4 times the amont of intake area for your exhaust.  In aviation a properly ducted reciprocating engine can actually produce a negative net drag because of the changes on air density and velocity  as it travels through the bay.

On the FJ it would be a matter of actually sitting down and looking critically at the heat sources, where you can get ambient air, and where you can dump it.  (Obviously you can't expect to take air that has already absorbed the heat of cooling the head and cylinders and expect to cool the turbo and exhaust with it.. .) But, if you keep your temperature deltas high, it's completely doable.

[ribbert]

There is a reason the exhaust valves are in front. Those exhaust valves need air flow, so the exhaust valves and manifold under the seat....Hmmmm
What could go wrong?

The turbo mounted low in front is superior for cooling and spool up.

Haha, doesn't seem to worry this guy.

https://www.facebook.com/groups/494216294033257/permalink/792569020864648/

Noel

[Pat Conlon]

Noel, I don't do Facebook so I can't log on.

Mike, many aftermarket turbo kits are made for various motorcycles. See the offerings by Mr. Turbo and Big CC Racing to name a few. These kits all mount the turbo low in front. Wheel clearance is not an issue nor is the oil drain. Google "turbo motorcycle pictures" you will see many more examples.

Putting a glowing cherry red exhaust manifold and turbine tucked away under your seat may sound like no big deal to you....or reversing the head so the absolutely hottest part of the engine is now located in the spot with the least airflow, well go ahead and flame away** all I can say is that, I wouldn't do it.

**Get it? Flame away? Where do I come up with this stuff?

[FJmonkey]

Got you covered Pat....

[ribbert]

Noel, I don't do Facebook so I can't log on.

I don't either, I didn't realise that was the link, below is a still from the video.



No comment necessary.

Noel

[skymasteres]

Pat, I'm seriously not trying to hijack jnimbostratus' thread. I just presented an idea that I'd been playing around with for some time. The idea was for a clean, efficient,  and less obvious install. I haven't seen any argument yet that shows a hurdle that is the Achilles heel of the concept.  Yes the heat is an issue, but it's not insurmountable.  I looked at some of those turbo low and forward setups.  Some of them are very clean and are definitely a good way to go if you don't mind hanging the turbo out like that.

One important note though for anyone reading this. IF a turbo is cherry red, it is NOT a happy turbo. It is being over driven.  (You'll  see promotional pictures of hot hard working turbos, but this is VERY bad for the turbo.) When metals are heated to those temperatures they expand then shrink when they cool. They actually shrink down to less than their original size.  (We used to take advantage of this when heating axel tubes to adjust a read end for more camber by shrinking the top of the tube to tilt the axes by about a degree where they entered the differential housing. ) Some of you have don't the same thing by heating your head stem bearing so it'll drop out. This shrinking will produce internal stresses in the turbo and eventually either Crack the housing or cause misalignment in the bearings and or turbine wheels.

The other big concept of turbo operation that I think is being missed is where the heat goes.  Turbos aren't jet engines. They're not little thermo nuclear devices that produce their own heat.  What they are is a way to harness the waste heat of the engine and extract work from it to compress the intake system. Yes there is a backpressure penalty,  but the heat is doing the heavy lifting. The exhaust gas exiting the turbo is actually significantly cooler than it was entering the turbo because of the energy that has been reclaimed to drive the complessor.

Are turbos hot?  Yes they are. But like every machine in this world,  they don't give you something for nothing.  They'll only get as hot as the volume of exhaust energy you put into them.  (They just let you make more power, which means more exhaust energy,  which means more power and so on till other factors limit scaling)

[Steve_in_Florida]

...I don't do Facebook so I can't log on.

And I thought *I* was the only one!

Steve

[Arnie]

...I don't do Facebook so I can't log on.

And I thought *I* was the only one!

Steve

I thlnk there are many of us who just don't see the point of Facebook, but do realize the dangers,  So, you're in good company Steve :-)

Arnie

[fj1289]

...I don't do Facebook so I can't log on.

And I thought *I* was the only one!

Steve

ditto

I thlnk there are many of us who just don't see the point of Facebook, but do realize the dangers,  So, you're in good company Steve :-)

Arnie

[fj1289]

I read thru your earlier posts - I see you are using a T3/4 hybrid turbo.  Where did you purchase it?  What is the AR of the turbine side?

Would you go with this turbo again - or try a different model if you were to try this again?

[jnimbostratus]

Wow totally didn't realize I had neglected to put my updates on this forum as I have been updating my build thread on the custom fighter forum. But first to answer the question about the turbo size. The only thing I may do differently would be a smaller ar48 hot side but I don't want to make that decision till after the fuel injection is done...

Since my last post on here I ditched my old plan when I scored a clean set of cbr1000rr throttle bodies for 22$ shipped. Fyi the spacing is about perfect. I will now post some pics.

[jnimbostratus]