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Turbo kit for Blackbird


grahamcuk

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You know, I was really wanting a larger pipe out of the turbo back to the "U" for the duals. Could flatten it to the od of the "U" making a oval hole. Maybe like 3" Overall diameter tube out of the Turb.

3" is too big....

Nope, the pipe leads from the turbo to a muffler or to a Y pipe to duals as an option.

I thought Stan was asking for a 3" pipe to go back to the Y pipe or where it splits for dual mufflers...

I think that is correct.

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You know, I was really wanting a larger pipe out of the turbo back to the "U" for the duals. Could flatten it to the od of the "U" making a oval hole. Maybe like 3" Overall diameter tube out of the Turb.

Would that be a posible?

Whats your reasoning Stan?

Something Forest showed me on his that I thought was a good idea.

That and the volume of the dual tubes is better served with a equal volume connector pipe to match the velocity and reduce pressure differential between the pipes. Cross section area of the two outlets should equal the cross section of the connector.

Is the turbo outlet reduced to the size of the connecting pipe or are they the same size at the flange?

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You know, I was really wanting a larger pipe out of the turbo back to the "U" for the duals. Could flatten it to the od of the "U" making a oval hole. Maybe like 3" Overall diameter tube out of the Turb.

3" is too big....

Don't think so.

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You know, I was really wanting a larger pipe out of the turbo back to the "U" for the duals. Could flatten it to the od of the "U" making a oval hole. Maybe like 3" Overall diameter tube out of the Turb.

Would that be a posible?

Packaging a 3" pipe out of the turbo would be very hard and I can't see any tangible benefits to doing so. The choke point of the exhaust system as spec'ed is the turbo body it's self not the exhaust. Any of the turbo’s we have spec’ed for road use would not achieve choked flow with the exhaust as spec’ed. Fitting of a GT3071R which is the biggest turbo that could be fitted to our header would require the fitting of a drag / dump pipe setup for race use but could still have to road system fitted with the boost tuned down to reasonable level for road .

Cheers

Graham

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What size is it?

Gt25r and GT28r ( not the GT28RS ) both have 48mm exhaust ports, the ID of the exhaust is 50mm . So the flow rate thought the turbine and exhaust port is less than the choked flow capacity of the exhaust. And the increase in pipe Dia would not do the torque figures any favours.

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What size is it?

Gt25r and GT28r ( not the GT28RS ) both have 48mm exhaust ports, the ID of the exhaust is 50mm . So the flow rate thought the turbine and exhaust port is less than the choked flow capacity of the exhaust. And the increase in pipe Dia would not do the torque figures any favours.

Bear in mind though that as the exhaust leaves the turbo it begins to expand almost immediately and benefits from the dump pipe -- 4-6% increase in power, so I can see why Stan wants the larger pipes.

On the other hand, I can also see how that complexity of fabrication would be a challenge for a small start-up.

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What size is it?

Gt25r and GT28r ( not the GT28RS ) both have 48mm exhaust ports, the ID of the exhaust is 50mm . So the flow rate thought the turbine and exhaust port is less than the choked flow capacity of the exhaust. And the increase in pipe Dia would not do the torque figures any favours.

Bear in mind though that as the exhaust leaves the turbo it begins to expand almost immediately and benefits from the dump pipe -- 4-6% increase in power, so I can see why Stan wants the larger pipes.

On the other hand, I can also see how that complexity of fabrication would be a challenge for a small start-up.

But surely for a road bike that will mainly be ridden off boost the loss of torque from the bottom end would not be worth the gains at the top end?

We are mainly looking at an entry level kit that will be running a max of 200bhp to give all round good road manners. We can fabricate pretty much anything if that’s what someone wants.

I need to keep my eye on the ball with the basic kit and not get too carried away with the exciting stuff.

Have a look at any of the picture of the blue bike that is the pipe and it fits straight to the aftermarket Art pro 2 slip-ons I did it this way so anyone who has already got slip-ons and wanted to use one or both could do so.

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Maan it has been a LONG time since we've had a good turbo thread like this!! :icon_clap:

Hi Buddy.

I take it you approve.........

Yeah, it's reminding me that I need to get out in the garage and get moving on the trike again!

What size is it?

Gt25r and GT28r ( not the GT28RS ) both have 48mm exhaust ports, the ID of the exhaust is 50mm . So the flow rate thought the turbine and exhaust port is less than the choked flow capacity of the exhaust. And the increase in pipe Dia would not do the torque figures any favours.

Bear in mind though that as the exhaust leaves the turbo it begins to expand almost immediately and benefits from the dump pipe -- 4-6% increase in power, so I can see why Stan wants the larger pipes.

On the other hand, I can also see how that complexity of fabrication would be a challenge for a small start-up.

But surely for a road bike that will mainly be ridden off boost the loss of torque from the bottom end would not be worth the gains at the top end?

I'm in over my head on this one -- I have no idea how it will change the experience as I have not had a street ridden turbo bike and experimented. I have toyed with some friends and their turbo busas, but they already had gobs of low end so max HP was the goal. I defer to your judgment and experience for sure.

I need to keep my eye on the ball with the basic kit and not get too carried away with the exciting stuff.
Yeah, I was alluding to that -- different exhaust options could be thought about later once you're up and running. Might be an upgrade option, but I would bet you have a few ideas on that already too.
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You know, I was really wanting a larger pipe out of the turbo back to the "U" for the duals. Could flatten it to the od of the "U" making a oval hole. Maybe like 3" Overall diameter tube out of the Turb.

3" is too big....

Don't think so.

Square root error.

Well... now with the port numbers I can say yes... 3" is too big. 2.5" would be best (for 48mm)... biggest I would recommend is 2.75". For what he states here....

What size is it?

Gt25r and GT28r ( not the GT28RS ) both have 48mm exhaust ports, the ID of the exhaust is 50mm . So the flow rate thought the turbine and exhaust port is less than the choked flow capacity of the exhaust. And the increase in pipe Dia would not do the torque figures any favours.

But... 2.5 Might even be to big, if there is not sufficient length... and there's a whole lot more too it....... like, what is the length of the collector pipe ?

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I am so looking forward to finalaization of what the stage 1 kit will cost. I am hoping I can purchase one. I recently just bought a Yoshimura SS 4-2-1 system for my 97 Carbie, had I known this Turbo was soon to be coming I would have just kept my slip on RS3's and saved the extra cash i spent towards this. I am curious as to what level of jetting will be required with this turbo kit on carbie if I cam currentley running a 4 degree ignition advancer with Dyna coils K&N and the Yoshimura 4-2-1

The entry level kit for me is all that is needed. Waiting eagerly on the launch of the Turbos.

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You know, I was really wanting a larger pipe out of the turbo back to the "U" for the duals. Could flatten it to the od of the "U" making a oval hole. Maybe like 3" Overall diameter tube out of the Turb.

3" is too big....

Don't think so.

Square root error.

Well... now with the port numbers I can say yes... 3" is too big. 2.5" would be best (for 48mm)... biggest I would recommend is 2.75". For what he states here....

What size is it?

Gt25r and GT28r ( not the GT28RS ) both have 48mm exhaust ports, the ID of the exhaust is 50mm . So the flow rate thought the turbine and exhaust port is less than the choked flow capacity of the exhaust. And the increase in pipe Dia would not do the torque figures any favours.

But... 2.5 Might even be to big, if there is not sufficient length... and there's a whole lot more too it....... like, what is the length of the collector pipe ?

48mm is the max Dia of the port not taking in to consideration the loss of flow area taken up by the turbine blades and shaft .

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If the goal is to make a very street able Turbo, and one that would have a dual outlet "Y" pipe, in order to run duals etc.

Then the goal of designing the Turbo's Exhaust header pipe would be too, maintain exhaust gas velocities, so that the low-speed spool up doesn't get stuffed, corked, or choked, by the downstream restrictions. (over cooling and flow velocity slowdown restrictions)

So... I would not come out of the Turbo with anything more than the 50mm initially.....

But it would be possible to gain some power without sacrificing the port velocity if the pipe was stepped up over it length correctly.

Hence why I asked what is the "Length" of the connector pipe ?

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Give or take a few mm it 500mm from the turbo port to the y peice 500m from the y peice to the start of the muffler and the muffler on my turbo bike is 500mm long.

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The splitting of the exhaust at the Y into to mufflers increases the volume at that point...

If you do all the calcs, you may find it to not be optimal but when faced with packaging constraints, there is only so much you can do.

I know of 1 turbo system from years ago on a Blackbird that uses the stock splitter and mufflers and it runs quite nicely.

In practice, removing the exhaust system completely and replacing it with a dump pump allows the turbo to spin up much faster,

I'm not sure that you can over exhaust a turbo, but I'm quite sure it possible to choke one down.

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I would be interested in the collector and Y pipe.

My turbo spinning through Mig exhaust would sound great!!

Depends on what the OD of your present exhaust is and where it runs...

Left or right 1/2" will throw it all off.

What turbo is on your bike?

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I happened to be at my cousins shop just couple of hours ago and certain blown ( smoke on the start up ) T17something was laying on the bench , those things are tinny .

The turbo was from 2000 Saab 9-3 .

Anyhow , 3 inch downpipe in this case would be an epic overkill of biblical proportions , 2-2.25 inch is just fine .

BTW , I`m running 3 inch or actually 80 mm downpipe on TD06sh 20g in my rx7 , and that is 350-400 whp turbo .

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With the turbo cars I normaly work with there is two schools of though , we either fit a small turbos that spool at 1500- 2000 rpm and gives a low level of boost across the rev range allowing a smooth increase in power without lag or we build the big horse power motors that spool at 4000-5000 rpm and the power comes in like a train hitting you in the back. personaly for road I would perfer the first option.

Attached are a couple of pic's of a car I have just finished for a customer, This uses a Turbo dynamics RCM450 hybrid the car weighs 1060kgs and is making over 550bhp from 2.1 L motor

post-53763-1323341666.jpg

post-53763-1323342003.jpg

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I would be interested in the collector and Y pipe.

My turbo spinning through Mig exhaust would sound great!!

Depends on what the OD of your present exhaust is and where it runs...

Left or right 1/2" will throw it all off.

What turbo is on your bike?

16g

header is from EFR- Elton

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I would be interested in the collector and Y pipe.

My turbo spinning through Mig exhaust would sound great!!

Depends on what the OD of your present exhaust is and where it runs...

Left or right 1/2" will throw it all off.

What turbo is on your bike?

16g

header is from EFR- Elton

Josh, is that a 2 1/4" pipe from the turbo back?

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Give or take a few mm it 500mm from the turbo port to the y peice 500m from the y peice to the start of the muffler and the muffler on my turbo bike is 500mm long.

Given those numbers I would leave it alone for the "street" kit.

The only except I would make to that is for the "Y" pipe connection... no let's call it what it is, the "T" pipe joint. A true "Y" pipe joint would be nice. but I'm not sure the benefits would be worth the work.

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