Advancement of fuel delivery?

[TurboTR]

Since you just use it for spool, I like the idea of making the pinwheel the sole nitrous system, with no need to switch to another. And if it works well, you could likely also reduce the size of the nitrous hit.

What I also really like about the idea is, it seems you also greatly reduce the charge cooling effect from expanding the nitrous. Which is one of the main things you were trying to accomplish- quit cooling down the charge so much. Now that cooling effect goes into cooling down a big part of the entry section aluminum of your intercooler. Which seems would also help pre-run cool much of its aluminum for a bit better performace down the track, under boost.

But the charge air coming out of the intercooler then would likely be much more moderate, compared to spraying directly into the intake air stream. Hosing upstream for ~ 3 sec only would probably never chill down the big ol' intercooler chunk of aluminum enough to greatly reduce the IAT from spraying.

3 birds with one stone maybe

Some diesel/nat gas engine projects I was involved with did in fact use the pinwheel spool technique, where the compressed air was supplied via the on board compressed air system (for the brakes). It does work. As a thrill back in the day (lol), I got to bench test one with a hand air valve connected to the shop air supply. It would spin up to near 20 thousand rpm in just a few sec if I recall (we had a tach on it too). Of course this was into no compressor load. The holes and such do not require too much engineering to get close. Intuition and careful thought can get you close enough.

Maybe to get a feel for it you could find an old dead stock turbo and experiment with like 1 hole to begin with, and just connect up your shop air tank. Or better than drilling several test holes, maybe you could mill out an acces slot in the housing, then just aim by hand (or with a jig) a thin piece of home made tubing nozzle (simulates a drill hole) at various angles and places until you find the sweet spot. Sounds like fun for a Friday afternoon.

If it winds up working well, I think you might then see an influx of compressor housings at DRW to drill for others Alot of imports probably, but still. And maybe some ruidmentary plumbing of it too- for a reasonable shop fee of course

TurboTR

Edit- just thinking out loud some more about the holes. Seems a great tactic would be to have like 3-4 of them, but NOT equally spaced. Offset the relative spacing such that at least one nozzle hole is always engaged with a compressor blade. As the wheel spins around. As soon as hole 1 pushes its blade away enough to be ~ ineffective (until its next blade comes around), hole 2 has engaged its blade now. Etc.

The one I tested did not have this offset spacing. If I recall it had like 6 holes, but all equally spaced. I bet it would have worked even better still with a clever offset scheme...

Edit 2- Seems you could experiment with that offset spacing idea using the milled access slot just by positioning 2 nozzles. Offset spacing work better than equal spacing (relative to the blade pitch)? Seems that would be easy enough to determine then.

 

[Alky V6]

What if a basic egr system were used to provide a certain percentage of egr at times of low egr associated with cam timing? For instance, my case. Cam egr drops to a low value between 4,000 to 4,500 rpm. If during that short window of time when the engine is working to spool the turbo, egr is introduced to help better dissociate the nitrous/methanol mixture, what might the outcome be?

 

[Alky V6]

Since you just use it for spool, I like the idea of making the pinwheel the sole nitrous system, with no need to switch to another. And if it works well, you could likely also reduce the size of the nitrous hit.

What I also really like about the idea is, it seems you also greatly reduce the charge cooling effect from expanding the nitrous. Which is one of the main things you were trying to accomplish- quit cooling down the charge so much. Now that cooling effect goes into cooling down a big part of the entry section aluminum of your intercooler. Which seems would also help pre-run cool much of its aluminum for a bit better performace down the track, under boost.

But the charge air coming out of the intercooler then would likely be much more moderate, compared to spraying directly into the intake air stream. Hosing upstream for ~ 3 sec only would probably never chill down the big ol' intercooler chunk of aluminum enough to greatly reduce the IAT from spraying.

3 birds with one stone maybe

Some diesel/nat gas engine projects I was involved with did in fact use the pinwheel spool technique, where the compressed air was supplied via the on board compressed air system (for the brakes). It does work. As a thrill back in the day (lol), I got to bench test one with a hand air valve connected to the shop air supply. It would spin up to near 20 thousand rpm in just a few sec if I recall (we had a tach on it too). Of course this was into no compressor load. The holes and such do not require too much engineering to get close. Intuition and careful thought can get you close enough.

Maybe to get a feel for it you could find an old dead stock turbo and experiment with like 1 hole to begin with, and just connect up your shop air tank. Or better than drilling several test holes, maybe you could mill out an acces slot in the housing, then just aim by hand (or with a jig) a thin piece of home made tubing nozzle (simulates a drill hole) at various angles and places until you find the sweet spot. Sounds like fun for a Friday afternoon.

If it winds up working well, I think you might then see an influx of compressor housings at DRW to drill for others Alot of imports probably, but still. And maybe some ruidmentary plumbing of it too- for a reasonable shop fee of course

TurboTR

Edit- just thinking out loud some more about the holes. Seems a great tactic would be to have like 3-4 of them, but NOT equally spaced. Offset the relative spacing such that at least one nozzle hole is always engaged with a compressor blade. As the wheel spins around. As soon as hole 1 pushes its blade away enough to be ~ ineffective (until its next blade comes around), hole 2 has engaged its blade now. Etc.

The one I tested did not have this offset spacing. If I recall it had like 6 holes, but all equally spaced. I bet it would have worked even better still with a clever offset scheme...

Edit 2- Seems you could experiment with that offset spacing idea using the milled access slot just by positioning 2 nozzles. Offset spacing work better than equal spacing (relative to the blade pitch)? Seems that would be easy enough to determine then.

I like the offset idea. I was envisioning the same thing.
The compressor housing is on the bench at the moment. I'm going to have to take a look at this.

 

[TurboTR]

If during that short window of time when the engine is working to spool the turbo, egr is introduced to help better dissociate the nitrous/methanol mixture, what might the outcome be?

Well, if you have no VVT, and no exhaust backpressure at the time relative to manifold pressure, how will you get EGR to flow into the intake?

TurboTR

 

[charlief1]

I'm following this but I could use a pic if you can provide it please. The holes in the wheel would also mean it would have to be rebalanced as well, right?

 

[Alky V6]

Well, if you have no VVT, and no exhaust backpressure at the time relative to manifold pressure, how will you get EGR to flow into the intake?

TurboTR

The spool valve would be closed causing a small amount of backpressure. The manifold would not be at 0 vacuum yet. There would still be some vacuum until the turbo started catching up. I would also imagine that boost pressure would lag behind exhaust pressure during initial spooling. Am I off on this assumption?
Something else I was thinking. After boost has built up, and with my boost to exhaust pressure ratio being less than 1:1, I would have boost pressure pushing into the exhaust. If a rich mixture were present with unburnt fuel in the exhaust, would I have an air injection system too?

Of course the flow in both instances, egr and air injection, would need to be metered.

I have an unused narrow band bung just before the turbo and I'm not using the IAC. I could fab a housing to replace the IAC housing easy enough. I would need a compact egr valve and a control solenoid. I can use an ecm gpo to control the egr valve.

Sounds like I'm loading the engine with smog devices now. The idea used to be to get rid of the smog devices.

 

[Alky V6]

I'm following this but I could use a pic if you can provide it please. The holes in the wheel would also mean it would have to be rebalanced as well, right?

The holes would be in the housing around the wheel. Not in the wheel itself.

 

[charlief1]

Well that's what I get for reading on the fly Donnie LOL

As far as an EGR valve you could use on off a series II 3.8 along with all of the tubing from what ever car you get it off. It's electronic and divorce mounted. The 3.4 Chevy has one as well and it may be the better choice. They both feed off the exhaust manifold so it shouldn't be hard to plumb in.

 

[Alky V6]

I'm spying the compressor housing now. With the anti-surge compressor housing, drilling the passages and plumbing the system will be a piece of cake. It would just be a matter of figuring out the angle for the hole exits. The ETT wheel may help make this system more effective too. More torque on the wheel from the gas.

There are four strut supports in this anti-surge housing inlet. So it looks like four holes will be it. They will not be staggered on the wheel though. They are equally spaced, each hitting a blade at the same point. Oh well. We'll go with the easy setup first and see how it works.

Todd. What do you think of a 90 degree hit to the blade with an outward angle from the centerline of the wheel. That way the gas would promote the flow through the comp wheel.

 

[TurboTR]

Think you'd have to draw us a picture to be able to follow

I think the max spin up effect would be to blow more towards the outer edge of the compressor blades. Angled holes pointing at the outer radius of the wheel. Not towards the inner radius.

Blowing at the outer edge gives the max torque on the wheel for a given amount of blow. This is also kindof how a garret VNT works. When flow is low it closes off the exh nozzle to raise back pressure and gas speed through the nozzle, BUT it also directs that speedier flow towards the turbine blade tips. Which maximizes the torque on the wheel. A nice 2 bagger.

TurboTR

Edit- maybe for starters, since your compressor housing is off, just start squirting the compressor blades with the shop air nozzle. That should be an easy way to give you a great feel for what would work best. Before you have to drill any holes or mill any slots. Just make sure there's some oil in your bearings

 

[Alky V6]

Think you'd have to draw us a picture to be able to follow

I think the max spin up effect would be to blow more towards the outer edge of the compressor blades. Angled holes pointing at the outer radius of the wheel. Not towards the inner radius.

Blowing at the outer edge gives the max torque on the wheel for a given amount of blow. This is also kindof how a garret VNT works. When flow is low it closes off the exh nozzle to raise back pressure and gas speed through the nozzle, BUT it also directs that speedier flow towards the turbine blade tips. Which maximizes the torque on the wheel. A nice 2 bagger.

TurboTR

I think you have the picture. Your explanation follows my thinking.
I'll post some pics tonight.

 

[Alky V6]

There are two angles that need to be worked out for these holes in the compressor housing.
X will be the angle that either points into the center of the wheel or out towards the outside of the wheel.
Y will be the angle that either points parallel with the centerline of the turbo shaft or at a 90 to the centerline of the turbo shaft when looked at from the side of the compressor wheel.

X angle looks to be most effective when it is at a right angle to the radius of the wheel, at the outer edge.

Y is not the most effective at a 45 degree angle, where it hits at a 90 degree angle to the blade of the wheel. It likes a more laid down angle. Drilling such a laid down angle would leave an elongated exit hole. I'm wondering how this might affect the compressor map of the compressor? Would the fins passing over these elongated holes near the tips of the blades create turbulence and upset the effficiency of the compressor?

 

[TurboTR]

Do some experimenting first before you go and drill up your good housing

The holes I have in mind are pretty small.

TurboTR

 

[Alky V6]

I hear ya. I'm going to hold off on these ideas until I see how the converter change pans out.

 

[pwr6kid]

Could you take the same idea and use it to accelerate exhaust wheel. Spray fuel and air in the exhaust before the turbo so the added volume will spin the turbo up faster? Ignite it with a spark plug mounted after the fuel and air entry point. I was thinking of an old hotrod flame thrower kit for the spark to the plug might work.
Jace Bigelow
I saw a post a few months back about how these work. Just thinking out side of the box.

Rich F.

 

[Alky V6]

Could you take the same idea and use it to accelerate exhaust wheel. Spray fuel and air in the exhaust before the turbo so the added volume will spin the turbo up faster? Ignite it with a spark plug mounted after the fuel and air entry point. I was thinking of an old hotrod flame thrower kit for the spark to the plug might work.
Jace Bigelow
I saw a post a few months back about how these work. Just thinking out side of the box.

Rich F.

Actually, I've heard of people doing just that. They did it with the turbo off the engine. They made their own little turbine engine. I've heard it does work very well. If you search YouTube, there are a lot of people making their own stand alone turbine jet engine out of an old turbo.

 

[pwr6kid]

Thats why I was thinking why not do it on the car?

 

[Alky V6]

Thats why I was thinking why not do it on the car?

Off the car, you can set up a separate combustion chamber. On the car, the combustion chamber would be the turbine housing. Not sure how long the turbo would hold up. Maybe short bursts just to spool would be OK. Isn't that kinda what racers are already doing with the 2-step spooling routine?

Speaking of 2-step spooling pre-launch. I understand that the routine is different for sticks and automatics. The stick or no-load procedure is pretty well known. A local tuner told me that with an automatic you want to increase timing (50 degrees btdc with gas) and shoot for a power mixture, not particularly overly rich. As the turbo starts to spool timing is backed away. This sounds a bit dangerous to me. How close are people running to detonation limits with this routine? I would guess that the turbo/converter combination is such that spooling is not really a difficult problem to begin with.

 

[Chevota]

Off the car, you can set up a separate combustion chamber. On the car, the combustion chamber would be the turbine housing. Not sure how long the turbo would hold up. Maybe short bursts just to spool would be OK. Isn't that kinda what racers are already doing with the 2-step spooling routine?

Speaking of 2-step spooling pre-launch. I understand that the routine is different for sticks and automatics. The stick or no-load procedure is pretty well known. A local tuner told me that with an automatic you want to increase timing (50 degrees btdc with gas) and shoot for a power mixture, not particularly overly rich. As the turbo starts to spool timing is backed away. This sounds a bit dangerous to me. How close are people running to detonation limits with this routine? I would guess that the turbo/converter combination is such that spooling is not really a difficult problem to begin with.

14:1 and 45deg timing worked well on my previous motor with no detonation problems. Releasing the t-brake reverted back to the normal fuel/timing strategy.

 

[Alky V6]

14:1 and 45deg timing worked well on my previous motor with no detonation problems. Releasing the t-brake reverted back to the normal fuel/timing strategy.

Holy cow! That follows what this fella suggested. Weren't you a little worried when you first tried that out?

If I hold on the T/C with anything in the 13s:1, the methanol wants to talk back to me. Let alone advancing to 45 degrees. I could probably get away with the 45 degrees, but the lean mixture would cause a kickback for sure.

Is this done against the T/C or at a rev limit under T/C stall?