The Official Hot Rod Thread - Part 4: Burnouts for Distance

[churchmouse]

This is kinda crazy...... But ingenious.

Think rotory with a power stroke every 33.3 degrees.

I love the tech involved here.

 

[RustyHornet]

EOIC….

 

[femurphy77]

EOIC….

View attachment 168373

Hey I have some of those!

 

[ChristianPatriot]

Cleetus McFarland had his 2.4 Hours of LeMullets event last night. I didn’t get to watch it this time, but apparently Kurt Busch pit maneuvered Kevin from KSR on the last lap to take the win. Which sounds exactly like something Kurt Busch would do.

 

[churchmouse]

EOIC….

View attachment 168373

I see some cool here. What am I looking at please. Has to be a Ford so go from there.....

 

[churchmouse]

Hey I have some of those!

Yup.

 

[RustyHornet]

I see some cool here. What am I looking at please. Has to be a Ford so go from there.....

Well it was supposed to be a numbers matching stock 302 in a ‘68 Shelby GT350. It came in for a re-seal and swapping out the 4 speed for an automatic because that’s how the car was born.

Found out that it is a 302 block, might be original, but it’s got 351 heads and stroker crank. So it’s a 347. Just fixing some things that the last builder screwed up…

Cam was wiped. Wrong push rods. Missing “t” washers around the head studs. Lots of issues.

New cam, matched springs, lapped the valves, Howard’s tie bar lifters, correct length push rods, comp roller rockers. Etc.

 

[jeffsqartan]

Working more on the turbo car this week.
Need some thoughts on the waste gate design/placement. This might get a little tricky, so buckle in.

For those un-initiated, I am building a COMPOUND turbo setup for a 351w. That means that the little turbo will get exhaust first, then remaining exhaust will feed into the big turbo. The big turbo will suck atmosphere air first, then send the compressed air into the intake of the little turbo, which will send that further compressed air into the intercooler and finally the engine.

Now, the little turbo I have selected is an HE351cw. It has an internal wastegate and utilizes a T3 housing. It's a fairly small housing, so I'm expecting this turbo to spool insanely fast.

I don't think that the internal wastegate is going to be able to come close to keeping up with the exhaust from the 351. My plan is to put an external wastegate on the setup and run both.

The trouble I'm running into is wastegate location. I'm not very confident that I can put the external wastegate in a location where it will be able to easily vent BOTH sides of the engine. However, I have a thought - what if I only vent one side? For instance, what if I only vent the passenger-side exhaust via the external gate? The gas is going to be fed into the big turbo anyway, so it *shouldn't* cause any pressure issues with one side of the engine not being vented. Furthermore, the driver side would technically be vented via the internal gate on the turbo.

It's a super weird idea and I'm curios to see what you guys think.

 

[Brad69]

Look at the Cat C-15 accert motors they used a compound set up.
Small turbo would spool fast. Then the big turbo would take over to the tune of about 40 psi.

Great bottom end performance. I cannot remember but I believe they only had one wastegate.

 

[jeffsqartan]

Look at the Cat C-15 accert motors they used a compound set up.
Small turbo would spool fast. Then the big turbo would take over to the tune of about 40 psi.

Great bottom end performance. I cannot remember but I believe they only had one wastegate.

The question isn't "will a single wastegate do the trick" but rather "if I put the waste gate in a position where it only gates one half of the engine, will that cause a backpressure issue."

Also, I'm basically cramming the entire exhaust into a tiny T3 housing flange. It's just a lot of exhaust moving into a very small space, which has potential to increase backpressure and cause issues. Adding the extra gate should help it spool the larger turbo faster while also relieving that pressure.

What I don't know is, if I only gate half of the engine, will it even out the pressure on it's own or will it do some kind of funky backpressure thing with one half of the engine.

I may just have to do it and put two back-pressure gauges on the car. Maybe a third. One for each half of the engine and one leading directly into the turbo to see what the turbo pressure is.

 

[Jaybird1980]

The question isn't "will a single wastegate do the trick" but rather "if I put the waste gate in a position where it only gates one half of the engine, will that cause a backpressure issue."

Also, I'm basically cramming the entire exhaust into a tiny T3 housing flange. It's just a lot of exhaust moving into a very small space, which has potential to increase backpressure and cause issues. Adding the extra gate should help it spool the larger turbo faster while also relieving that pressure.

What I don't know is, if I only gate half of the engine, will it even out the pressure on it's own or will it do some kind of funky backpressure thing with one half of the engine.

I may just have to do it and put two back-pressure gauges on the car. Maybe a third. One for each half of the engine and one leading directly into the turbo to see what the turbo pressure is.

The wastegate exhaust will still be directed to the larger turbo right?
If so I would think it would even out, but I'm not a turbo guy.

Could you run the small turbo off of one bank and then the exhaust from that turbo and the other bank exhaust into the larger turbo?

 

[jeffsqartan]

The wastegate exhaust will still be directed to the larger turbo right?
If so I would think it would even out, but I'm not a turbo guy.

Could you run the small turbo off of one bank and then the exhaust from that turbo and the other bank exhaust into the larger turbo?

Yes, it would still be directed into the bigger turbo.

What you're suggesting is kind of what I'm wondering would effectively happen. I would be putting the gate right before the turbo at the collector. So if the gate opens, theoretically it would vent that bank directly into the big turbo.
AKA - system starts off with both banks lighting the little turbo, then quickly moves to one bank lighting the big turbo. At least in theory.

 

[Jaybird1980]

Yes, it would still be directed into the bigger turbo.

What you're suggesting is kind of what I'm wondering would effectively happen. I would be putting the gate right before the turbo at the collector. So if the gate opens, theoretically it would vent that bank directly into the big turbo.
AKA - system starts off with both banks lighting the little turbo, then quickly moves to one bank lighting the big turbo. At least in theory.

As long as the piping was sized big enough I imagine it would work, but hell I don't know anything.

 

[Brad69]

Talked to a Cat guy He said the small turbo will feed the big turbo. Like you explained but that’s for a I6 don’t know if the V8 would change the equation?

My brain hurts trying to think about it!

 

[jeffsqartan]

Talked to a Cat guy He said the small turbo will feed the big turbo. Like you explained but that’s for a I6 don’t know if the V8 would change the equation?

My brain hurts trying to think about it!

So actually, on compound setups the little turbo is fed by the big turbo.
Exhaust enters the little turbo first, then goes out the little one and into the big one.
For intake air, the big turbo sucks atmosphere air, compresses it and sends it into the intake of the little one. Little one then spits the air into the intercooler and then the engine.

 

[ChristianPatriot]

So actually, on compound setups the little turbo is fed by the big turbo.
Exhaust enters the little turbo first, then goes out the little one and into the big one.
For intake air, the big turbo sucks atmosphere air, compresses it and sends it into the intake of the little one. Little one then spits the air into the intercooler and then the engine.

Depends on your definition of “feed”. The exhaust gases from the small turbo “feeds” the big turbo.

 

[ChristianPatriot]

Best practice I’ve seen pretty consistently across turbo builds is to put the wastegate as close to the collector as possible while maintaining good flow. Putting it 90 degrees to the exhaust piping anywhere in the system will not allow you any control.

 

[jeffsqartan]

Best practice I’ve seen pretty consistently across turbo builds is to put the wastegate as close to the collector as possible while maintaining good flow. Putting it 90 degrees to the exhaust piping anywhere in the system will not allow you any control.

I agree with this.

 

[churchmouse]

I ferreting. I have mapped this out in my warped addled little brain.
Look forward to see what you come up with in reality.

 

[RustyHornet]

Photo dump as this ‘51 Chevy is coming to an end. Just a few things to button up.