Casper's Twins first dyno.

[McRat]

Drive pressure gauge wasn't behaving, I need to work on again.

What's the drive pressure on other setups at 4500rpm WOT? Or EGT's? I really don't know. I do know that EGT's climb rapidly after 3800 in all dmaxes I've worked on.

Turbo boost climbing into redline for racing applications is normal. If your boost starts fading, the charger is too small.

 

[1lowdiesel]

nice start pat congrats.

 

[dmaxvaz]

Drive pressure gauge wasn't behaving, I need to work on again.

What's the drive pressure on other setups at 4500rpm WOT? Or EGT's? I really don't know. I do know that EGT's climb rapidly after 3800 in all dmaxes I've worked on.

Turbo boost climbing into redline for racing applications is normal. If your boost starts fading, the charger is too small.

if turbo boost stops climbing; it could be a # of things- it could mean that the wastegate dumps to early or doent hold, not enough fuel, charger too small, drive psi too high. my drive psi at 3800-4000 rpm was 1.3 to 1 with the stock charger and the s400. the egt s would stay around 1400* and would creep slowly to 1550*

 

[McRat]

if turbo boost stops climbing; it could be a # of things- it could mean that the wastegate dumps to early or doent hold, not enough fuel, charger too small, drive psi too high. my drive psi at 3800-4000 rpm was 1.3 to 1 with the stock. the charger and the s400. the egt s would stay around 1400* and would creep slowly to 1550*

What was it at 4500? Big difference between 3800 and 4500.

That's the difference between 174mph and 209mph.

 

[Subman]

if turbo boost stops climbing; it could be a # of things- it could mean that the wastegate dumps to early or doent hold, not enough fuel, charger too small, drive psi too high. my drive psi at 3800-4000 rpm was 1.3 to 1 with the stock charger and the s400. the egt s would stay around 1400* and would creep slowly to 1550*

I don't believe these turbos have wastegates do they?

 

[McRat]

Nope, ungated and running well within their maps, almost dead center.

 

[Subman]

Well good luck with it Pat, you are breaking new ground with those RPM's will you be racing Casper in Phoenix on the 7th or not?

 

[Kat]

Well good luck with it Pat, you are breaking new ground with those RPM's will you be racing Casper in Phoenix on the 7th or not?

We are waiting for the hamsters soccer and softball schedules to come out. Won't know for sure until the mid of February.

 

[Huntinducks82]

Great #s Pat. Just wonderin how far do think you will have to travel to reach 200mph. How long is the track or sand flats i guess they call it.

 

[McRat]

We want to do it on the "short course", which is:
0-1 mi unclocked
1-2 clocked for record
2-2.25 clocked for long course qualifying, must be over 175.
2-3 clocked for record.

So if you can hook up, you can set a record in 2 miles.

But most folk running 200+ use the long course, which is 5 miles.

 

[jonathancasey19]

you could always close your eyes and spray the piss outta it like the dodge boys do

 

[bigbird]

Nope, ungated and running well within their maps, almost dead center.

Why no gates? would they not help with heat and pressure, as well add HP.

Kelly

 

[dmaxvaz]

Why no gates? would they not help with heat and pressure, as well add HP.

Kelly

i think the high pressure turbo (the one that is fed by the up pipes) should be gated so to let the larger one spool more and the smaller less to manage drive pressures and heat. the larger atmosphere charger shouldnt need a gate

 

[McRat]

Not sure about the wastegate thing. No, it has no wastegates.

 

[bigbird]

Pretty sure with talking with a few twin builders you would free up about 100HP in your application with a wastegate.

 

[dmaxvaz]

I think it would be worth a try; wouldnt hurt, it would work good on dialing in the twin setup better. Dump the drive pressure from before the smaller turbo into the hot pipe driving the larger turbo harder

 

[TrentNell]

Pretty sure with talking with a few twin builders you would free up about 100HP in your application with a wastegate.

i dont see how a wategate could add 100 extra horse power unless you were exceeding the map on one of the turbo's ? but i am no twin expert .

 

[bigbird]

i dont see how a wategate could add 100 extra horse power unless you were exceeding the map on one of the turbo's ? but i am no twin expert .

I am trying to learn as well. I have talked to 3 different people that install twins, and if all things are equal the wastegated twins will make 75-100HP more than the non gated.

 

[1badmax]

I am trying to learn as well. I have talked to 3 different people that install twins, and if all things are equal the wastegated twins will make 75-100HP more than the non gated.

I gated both my turbos just incase i run nitrouse i have a way to control boost on the big turbo. I have alot to learn with were to set the waste gates (so i am no expert ) due to finishing the trk at the end of the year and not alot of track time. But the big twins are fun and dangerous at the same time, ask tony at ridge runner and Big dipper.

 

[super diesel]

i dont see how a wategate could add 100 extra horse power unless you were exceeding the map on one of the turbo's ?

This right on the money. Need the turbos in the juicy part of the map at any case. If they run there with out gates they wouldn't be able to take advantage of them if they were there any way. This is what there made for (venting just enough exhaust to keep the turbos RPM down to the sweet spot). Suppose the 42 was at 95k-105K (big drive pressures too) but the big one was at 40K rpm. You could vent some gasses off the 42 to get it to 65k-75k and feed the rest to the 55 and make it go to 45k-65k rpm. If you do it right (for a particular elevation), You can size the A/R on the exhaust to do this. However if elevation takes a decent change (or the D.A.) the waste gates control this (turbo shaft RPM, back pressure to get in the juice of the map) and you can run smaller exhaust housing A/Rs for quicker spool up. I think Pat and PPE are shooting for around 45k-50K rpm on the 55 would be my guess to keep it around 75psi boost? These are approximates and would have to be adjusted accordingly to keep things where you wanted them (testing and fine tuning). This is where speed sensors, and drive pressure gages would be invaluable.

There see! Clear as mud eh?