Builds My turbo build...FINALLY! (2 Viewers)

[landtank]

Are you planning on mounting the turbo intercooler next to the tranny radiator?

the heat exchanger will be on the PS in front next to the tranny cooler. The one that I'm going with first will support the SC but I'll need to test it to see if it's adequate for the turbo since the turbo will generate more heat.

 

[concretejungle]

as usual, i'm interested in seeing what you cook up!

 

[dagwood85]

We need more!

 

[yoda-g3]

At the beginning of this you mentioned that you were going to go with a .83 A/R exhaust housing but your closeup in post #231 showed a .70. Just curious why you changed it and what trim are you running?

I just found out mine is cracked and trying to decide if I should change things when I replace it. Currently running 50 Trim& .82 A/R.....

 

[landtank]

At the beginning of this you mentioned that you were going to go with a .83 A/R exhaust housing but your closeup in post #231 showed a .70. Just curious why you changed it and what trim are you running?

I just found out mine is cracked and trying to decide if I should change things when I replace it. Currently running 50 Trim& .82 A/R.....

The hot side is .83. what is shown in that pic is the cold side, compressor side.

 

[yoda-g3]

The hot side is .83. what is shown in that pic is the cold side, compressor side.

Lol, thanks. I'm new enough to turbo specs I didn't realize they stamped a similar ratio on the compressor. I should've looked closer.

 

[Tyler93]

Updates?

 

[dagwood85]

Updates?

X2 been watching this one for a while now.

 

[landtank]

I've been working off and on designing the intercoooler system. I have a 2" thick heat exchanger mounted on the front and am trying to position it so a pusher fan can also be mounted behind the grill.

I've taken a week's vacation in October with hopes of being ready for the final push to finish off the project.

 

[cruiserjb]

subscribed!

 

[Madness]

I am not sure how I missed this thread.

Brilliant execution of a home built turbo system. Rick kept the exhaust manifold volume down by casting his own manifold. The volume between the turbine and exhaust valves plays a BIG role in turbo lag.

Using a Water to Air IC also kept intake volumes in check. Great text book design.

Now estimating power is easy.
The formula for HP is CIDxPRx.0532
The formula for TQ is CIDxPRx.069

Horsepower
Stock = 275x14.5x.0532=212HP
7psi of boost 275x21.5x.0532=314HP
10psi of boost 275x24.5x.0532=358HP

Torque
Stock = 275x14.5x.069=275TQ
7psi of boost 275x21.5x.069=407TQ
10PSI of boost 275x24.5x.069=464TQ

All the above assumes a proper tune and MBT can be reached with fuel available. The stock CR is low so I don't expect a problem with 93 oct. Our California 91 can be a tricky so who knows there. Factory cars with 8.5CR boost between 7 and 10 PSI on a regular basis. Either boost levels the extra torque will really help move things along.

 

[MS-75]

Try running the same sized turbo on a very basic, log type exhaust manifold, and then on a runner style one with smooth transitions (but much bigger internal volume) and see how that pans out..........

 

[Madness]

Try running the same sized turbo on a very basic, log type exhaust manifold, and then on a runner style one with smooth transitions (but much bigger internal volume) and see how that pans out..........

I already know cause I have done both on other cars. In the end packaging dictates the best solution.

We got 500WHP on a 3.2 ltr VR6 with a GT35 on a log manifold.

They are not a significant source of restriction. Not worth the minimal gains of fabbing up weld EL's and making something that "should" be better but in the real world is not.

I watched a local Porsche shop spent 5k making headers from 321 and see zero gains from factory manifolds that look like crap. I have been playing with turbos long enough to know what works and what does not. What Rick has here is better than anything else I have seen for the Landcruisers to date.

If you want to make equal length header type manifold you will not see more than a 25hp-30hp benefit. Not worth the trouble IMHO.

 

[MS-75]

I think you need a little more experience in the field.

 

[landtank]

the design criteria was a 10psi system using a GT35r. For that I think a log style manifold is just fine.

You want to weld up a fancy manifold instead have at it.

As an update I have been working on it and the reservoir tank/pump is done as well as the mounting brackets for the heat exchanger. The inter cooler has been identified and I still need to design brackets for that and the intake tube going from the air filter to turbo inlet.

hopefully this will be the year.

 

[MS-75]

Nothing amiss with your set-up considering the low boost and max HP targets.

If creating the same type of package I would do no different.

It is very tidy and well executed.

 

[mmeister13]

This is an awesome thread and can't wait to see how it turns out.

Since I am currently working on a turbo build, not on my 80 but a school team www.wreckracing.com, I have done a lot of research on turbo exhaust systems. Log manifolds work great for cars that need power at low boost, typically at low rpm. Equal length runner manifolds work best for power in the higher rpm range, which is why you see drag cars and F1 (back in the day) running equal length.

After doing ~30 SolidWorks flow simulations I can definitely say there is a huge difference between log and runner manifold and both have their strengths and weaknesses in all applications.

 

[Madness]

I have done a lot of research on turbo exhaust systems. Log manifolds work great for cars that need power at low boost, typically at low rpm. Equal length runner manifolds work best for power in the higher rpm range, which is why you see drag cars and F1 (back in the day) running equal length.

You are correct but are missing some important information. Generally speaking equal length headers are needed at high RPM's to minimize TIP. When a motor is tuned for high RPM operation the cams have overlap. That overlap allows exhaust pressure (which is greater than boost by sometimes double) to push the clean air charge back into the intake. The longer length affects spool but who cares on a race car cause you live way up in the RPM band anyway.

Here is a car I did about 4 years ago. I still own it today. Makes 500hp at the crank on 7psi of boost.

I also did another build on the same type of car 8 years ago That one used factory manifolds (not quite log but not header either). That one was 600hp but needed 20psi to get there. On the street the car with the factory manifolds was much more fun to drive. Boost response was fantastic. Power was always there between shifts. The car with headers (and cams) is much better on the track but on the street it does suffer from boost drop (ie lag) between shifts at lower RPM's. Both cars used the dual GT2860 disco potatos. Can't get a much better comparison than that.

Building turbo systems from scratch is fun. Keeping realist goals in mind and being honest about the application will result is a happy build everytime.

 

[mmeister13]

You are correct but are missing some important information. Generally speaking equal length headers are needed at high RPM's to minimize TIP. When a motor is tuned for high RPM operation the cams have overlap. That overlap allows exhaust pressure (which is greater than boost by sometimes double) to push the clean air charge back into the intake. The longer length affects spool but who cares on a race car cause you live way up in the RPM band anyway.

I figured I wouldn't get into the technical stuff but yes that is the logic behind my answer.

Also is that a twin turbo legacy?

 

[Madness]

I figured I wouldn't get into the technical stuff but yes that is the logic behind my answer.

Also is that a twin turbo legacy?

I was dancing around it to but some don't quite get the logic. Bottom line is compact exhaust manifolds work best on most street applications. Equal length headers work best on race cars.

It's a 96 911 turbo.