Monty’s Single Turbo -> Back to Twins (Compound)

[Monty23]

^^^ more info PLEASE

[MadAudi]

Soon....

[Monty23]

Intial log of my 6262 vs. my 5858

5858 - 2.7 FATS in this log
6262 - 3.0 FATS in this log
Both logs are on the exact same tune. (PT5858 meth base tune)

[AudiSportB5S4]

Guess you'll have to turn up the boost on that 6262 to make it worth the change!

[Monty23]

Yeah 500 rpm spool difference. The 6262 definitely has a lot more in it, just need to work on the tune... and this crazy heat wave needs to go away!

[AudiSportB5S4]

Definitely!! What was the ambient when you logged the 5858?

[Monty23]

5858 - probably around 65-70, the 6262 was logged in 85F with high humidity. Car feels faster than Wednesday night when I logged it.

[Audi_S4]

I bought the PT5858 .63 BBing for my 3.2 VR6 A3 ... I wanna make 600chp with it (500whp) , rev limiter around 7500rpm with DSG

Guess I'll have to sell it and get a 6262 .82 when I read this ?

Doe sit really fall on it's face up top due to the turbo or is it intake related?

[MadAudi]

I'm still working on the tune/logs with my 6266, hopefully I can give my .02 soon.

[Meow]

was great meeting you this weekend! Wrenching on lees car was fun/hard work all at the same time! lol.

when you get a chance? http://www.audizine.com/forum/showth...idation-thread

loved the car man, sounded brutal when you went for some logging.

[Monty23]

The PT6262 is starting to look better! 2.71 FATS last night, still need to dial in the fueling for 100% meth and up the timing a bit ;)

[Monty23]

And acceleration: 5858 vs. 6262

[SpeedWorksAuto]

Wow, looks like it will just keep pulling hard to redline! Where is your redline set?

[Monty23]

Redline is at 7500. As you can see I ended the run early since I was road limited on my last few logs lol. I wish the roads around me were like the ones around BT!

[AudiSportB5S4]

Nice man.. By the looks of it though, the 5858 still has the benefit to the lower RPM where the 6262 is spooling up to power still, then they hold the same accel. to redline?

Solid though.. Love how easy these STKs are breaking into high 2s for FATs.. Impressive for sure.

[Monty23]

Yeah the 5858 will be better off the start of a race for sure, but when I shift I will be put back into a better power band with the 6262. It's all about compromises for sure!

I can't wait to install built 2.8 CNC's heads with supertech valve train so I can see what this 6262 can do at 8000+rpm!

Anyone want to donate a proper intake manifold/TB

[spd579]

And acceleration: 5858 vs. 6262

Here's your sign.....the main difference here is the turbine housing, not the turbo IMO..........I could be wrong but I wish youd try that tubine on the 5858. It would def finalize my decision for what turbo i'll be using if you dont mind

[spd579]

Yeah the 5858 will be better off the start of a race for sure, but when I shift I will be put back into a better power band with the 6262. It's all about compromises for sure!

I can't wait to install built 2.8 CNC's heads with supertech valve train so I can see what this 6262 can do at 8000+rpm!

Anyone want to donate a proper intake manifold/TB

I have a RS4 TB for sale.......

[Monty23]

Here's your sign.....the main difference here is the turbine housing, not the turbo IMO..........I could be wrong but I wish youd try that tubine on the 5858. It would def finalize my decision for what turbo i'll be using if you dont mind

I'll probably buy the .82ar hsg for my 6262 when I install my built heads to see if there are gains... But both turbos have the .64ar hsg currently...

[Monty23]

I have a RS4 TB for sale.......

Keyword being "donate" lol

[spd579]

Oh wow.....NM then......I thought you were using the .82 with that 6262. Looks like I'll be going with that 6262. I would like to see the difference a .82 turbine housing makes......might only make spool worse.....

And this definetly confirms my GTX 3071 I was considering using would be a complete dud above 5000.....

[Monty23]

Obviously stock heads, intake manifold, and tb contribute to the power not holding, maybe more so then the turbo?

[spd579]

Obviously stock heads, intake manifold, and tb contribute to the power not holding, maybe more so then the turbo?

I dont believe so.......if the heads, IM and TB flowed better and the turbo is the choking point.........the power could come on sooner, faster and would def peak higher but would choke even worse up top because the turbo would be choking out. If that makes sense?

[spd579]

Keyword being "donate" lol

I'm willing to donate to you if you're willing to donate to me

[jibberjive]

And acceleration: 5858 vs. 6262

What are your vehicle setting in ECUxPlot? Have they been changed from stock at all?

[Monty23]

What are your vehicle setting in ECUxPlot? Have they been changed from stock at all?

Mass = 1700
RPM per mph = 68.8
Coef of drag = 0.31
Frontal area = 2.034
Driveline loss % = 25.0

[Monty23]

So I did back-to-back testing tonight with my BB PT6262 .64AR turbo and my BB PT5858 .64AR turbo.

I did both these logs on the exact same stretch of road, the road was very flat and had a nice white line across it that I used to start each pull. I drove very easy before each pull was made do get consistent results.

First up was the PT6262. Then after I got home I had to let it cool for 45 minutes before I could pull it off since it was too hot to handle. Then about an hour and 15 minutes later I tested the PT5858. In the time it took to swap turbos, the ambient temperature outside dropped about 5 degrees. The only thing changed on the car was the turbos. The tune and everything else remained exactly the same.

Here are the logs:







This last graph is hard to read, but on the 6262 log - I only pulled 1.5 cf up until 5000rpm and then I was at 0 cf for the rest of the pull. On the 5858 log, it pulled about 2.25 cf the whole pull.

As you can see the PT5858 is clearly the winner over the first half of the pull, but the PT6262 shines up top. Britishturbo is going to overlay my two logs in virtual dyno as well.

[Monty23]

And here is a modified FATS that better resembles how I would drive the car if I was racing.... 4500rpm - 7300rpm

[britishturbo]

Here's your sign.....the main difference here is the turbine housing, not the turbo IMO..........I could be wrong but I wish youd try that tubine on the 5858. It would def finalize my decision for what turbo i'll be using if you dont mind

You know you can't swap housings between the 5858 and 6262 right?
The 558 has a 59mm turbine bore and the 6262 a 63mm bore.

[britishturbo]

Oh wow.....NM then......I thought you were using the .82 with that 6262. Looks like I'll be going with that 6262. I would like to see the difference a .82 turbine housing makes......might only make spool worse.....

And this definetly confirms my GTX 3071 I was considering using would be a complete dud above 5000.....

Of course the 0.82 hot side will make spool worse... that's how it works lol... slower spool but more flow capability.
And for sure the 3071 or 5858 are too small for your power goals...

[jibberjive]

I like the controlled conditions

Turbo selection and powerband is a matter of personal preference, so I must ask, what is your personal preference between the two as they stand, the 5858 or the 6262?

[Monty23]

I like the controlled conditions

Turbo selection and powerband is a matter of personal preference, so I must ask, what is your personal preference between the two as they stand, the 5858 or the 6262?

I absolutely....100% prefer the 6262 over the 5858. The 500 rpm that I lose by running the larger 6262 (which is null if I start racing above 3500rpm, who races below 3500 rpm lol) is easily made up for in the 6000+ rpm range.

That being said, it would be interesting to test the other two exhaust housings, a PT5858 with the .82 AR housing might be ideal for a motor with rods and no intention of doing built heads....

As you can see in my log from ATCO dragway, after I shift I am dropped right into the start of 6262's powerband, however each shift drops me into the top portion of the 5858's powerband which dies out above 6250rpm. keep in mind, second gear with the 6262, I make full boost around 5000rpm...

[SpeedWorksAuto]

I really like where this is going. You lost some down low, and gained up top with plenty of room to go with tuning.

[spd579]

You know you can't swap housings between the 5858 and 6262 right?
The 558 has a 59mm turbine bore and the 6262 a 63mm bore.

Ummm I know they make a .82 A/R houing for both

Of course the 0.82 hot side will make spool worse... that's how it works lol... slower spool but more flow capability.
And for sure the 3071 or 5858 are too small for your power goals...

Sooooooo what would the 5858 look like with a .82 A/R housing? Something between these two turbos tested above? I'm looking a mean street machine.....not race cars like you guys. If I could have k03's to start and 6262 take over at 4k I'd be in heaven.......

[Monty23]

Ummm I know they make a .82 A/R houing for both


Sooooooo what would the 5858 look like with a .82 A/R housing?

You should let us know I still don't think the 5858 will be any fun over 7Krpm.... but I would love for you to prove me wrong!

[spd579]

I'm not sure if I want to buy one just to fiddle around with it and end up buying a 6262......

How about we donate to each other!?! I'll donate a RS4 throttle body to you and you donate your 5858 to me, I'll get a larger exhaust housing and test!! haha

[spd579]

And here is a modified FATS that better resembles how I would drive the car if I was racing.... 4500rpm - 7300rpm

Isn't BT putting down like 2 sec FATS??? is his car really that much faster????

[britishturbo]

Ummm I know they make a .82 A/R houing for both


Sooooooo what would the 5858 look like with a .82 A/R housing? Something between these two turbos tested above? I'm looking a mean street machine.....not race cars like you guys. If I could have k03's to start and 6262 take over at 4k I'd be in heaven.......

The 5858 will run out of steam before any gain the 0.82 would give you would be seen.

It's always a compromise. You can't have k03 spool and 6262 power... just like I can't have 5858 spool and my 6766 power lol.
Well... I can... with my nitrous haha.

The biggest deciding factors are how much peak power do you want, how big of a power band do you want, where do you rev to and how will you drive it.
Maybe I should make a chart of all the data I have lol.

[britishturbo]

Isn't BT putting down like 2 sec FATS??? is his car really that much faster????

With nitrous I did 1.95 FATS for 4200 to 6500.
Let me see what that works out to be at 4500 to 7300...

[britishturbo]

And here is a modified FATS that better resembles how I would drive the car if I was racing.... 4500rpm - 7300rpm

Using your modified fats... I get 2.45 seconds