Precision Pt6766 Vs Forcedperformance Gt3794R Hta Dyno Shootout

[Lithium]

Hi guys, various billet turbos have come up in various threads on here of lately - particularly the Precision CEA range and occasionally the ForcedPerformance HTA range.... recently one of the more respsected DSM/EVO tuners in the US did a really thorough test between the "big guns" of the T3 range from both companies and posted a thorough post detailing the results.

I figure people here might find it interesting reading, granted the boost levels are way beyond what most here will look into - but still we all like to read about boost and hp It's worth noting the Mustang Dyno that Boostin Performance use tend to give results which seem fairly comparable with Dyno Dynamics, not your typical "inflated" American dynos. The car in this thread typically traps at >170mph and has a PB of 8.27 so far.

I digress:

Test vehicle: 96 Eagle Talon TSI "Red Demon"

• Boostin Performance Built 2.0L 4G63' date=' 10:1 comp[/font']
  
• Boostin Performance Built 6 bolt Head, Kelford 280's, Magnus Cast Intake Manifold, T3 Punishment Exhaust Header
  
• ID 2000's, Dual Bosch 044 Fuel pumps, KB boost-a-pump, E70 race fuel
  
• AMS Evo 8 Race core IC, Full 3" intercooler piping
  
• AEM EMS S1, SparkTech C.O.P.
  

Turbochargers:

Precision BB 6766

PTE "Ported S" compressor cover which has a 4" inlet/2.5" outlet

PTE T3 .82 A/R Turbine housing with a 3" V-band outlet

PTE compressor is 67mm Inducer , 87mm Exducer - Turbine Inducer 74mm, Exducer 66mm

Forced Performance 3794 HTA

Garrett Ported T4S compressor cover which has a 4" inlet/2.5" outlet

Garrett T3 .82 A/R Turbine housing with a 4 bolt 3" outlet

FP compressor is 67.5mm Inducer , 94mm Exducer - Turbine Inducer 72mm, Exducer 65mm

The FP3794 basically has a bigger compressor wheel but a smaller turbine wheel when compared to the Precision 6766. The FP 3794 also has a 7+7 blade compressor wheel compared to the 6+6 blade on the 6766 compressor wheel.

After running both turbos on my car the results were so close that I had to do back to back testing on the dyno to know for sure which turbo had the edge.

Dyno:

I went to the Mustang Dyno with an open mind and both turbos ended up surprising me. Pulls on both turbos were done @ 37, 42, 47, 52, and 55 psi. Timing was untouched for the duration of the testing and fueling was only adjusted to match airflow from each turbocharger. Target AFR was the same for all the testing. Each pull was done once the coolant temp hit 150 degrees - looking back at the logs every pull was done between 150-155 deg. coolant temp. Tire pressure was kept @ 25 psi and was checked numerous times during the test to ensure an accurate comparison between pulls.

After the pulls were done on the PTE 6766, the car cooled for about 1/2 hour while we ate dinner. The FP 3794 was swapped on without the car ever coming off the dyno.

I usually run an AEM BCS tuned with the AEM EMS so I can run boost by gear. For this test I installed a Hallman Pro RX MBC to make boost adjustments quick and easy. I have always used the dyno as a tool to help get my tune close, and then I finish the final adjustments at the track, but not this time. I pushed the car harder than I ever have and ended up burying the MBC on both turbos. With the MBC maxed out, the PTE 6766 saw 55 psi and the FP 3794 maxed out @ 53-54 psi.

Conclusion:

Both T3 turbos are unbelievably potent for their size. Turbocharger technology has sure come a long way in the past 5 years. Both turbos have trapped 170+ mph and gone mid 8’s in my 96 Talon.

In my testing, the Precision turbos power band came in sooner but didn’t have the top end of the FP. This is seen at every power level, but is very evident on the 42 psi and 47 psi dyno sheets. In the higher boost levels (50’s) the Precision turbo seems to make up the ground on the FP. I believe this is because of turbine backpressure, but it's impossible to be sure without a backpressure sensor being logged. Both turbos are great and I'm not sure which one I would consider the winner. Each turbo is better in different ways, so you can use this information to make the call for yourself.

37 psi dyno sheet

5800 - FP 30 psi - PTE 34 psi

6500 - FP 35 psi - PTE 37 psi

7200 - FP 37 psi - PTE 37 psi

8000 - FP 38 psi - PTE 37 psi

8700 - FP 37 psi - PTE 37 psi

9400 - FP 35 psi - PTE 35 psi

42 psi dyno sheet

5800 - FP 33 psi - PTE 36 psi

6500 - FP 41 psi - PTE 41 psi

7200 - FP 42 psi - PTE 42 psi

8000 - FP 42 psi - PTE 42 psi

8700 - FP 41 psi - PTE 40 psi

9400 - FP 39 psi - PTE 39 psi

47 psi dyno sheet

5800 - FP 33 psi - PTE 39 psi

6500 - FP 46 psi - PTE 47 psi

7200 - FP 47 psi - PTE 47 psi

8000 - FP 47 psi - PTE 47 psi

8700 - FP 45 psi - PTE 45 psi

9400 - FP 42 psi - PTE 41 psi

52 psi dyno sheet

5800 - FP 33 psi - PTE 40 psi

6500 - FP 46 psi - PTE 51 psi

7200 - FP 52 psi - PTE 52 psi

8000 - FP 52 psi - PTE 51 psi

8700 - FP 49 psi - PTE 48 psi

9400 - FP 47 psi - PTE 46 psi

55 psi dyno sheet

5800 - FP 33 psi - PTE 40 psi

6500 - FP 46 psi - PTE 52 psi

7200 - FP 53 psi - PTE 55 psi

8000 - FP 53 psi - PTE 53 psi

8700 - FP 49 psi - PTE 50 psi

9400 - FP 48 psi - PTE 48 psi

Original thread here: http://forums.evolut...erformance.html

Cheers

[Frosty]

interesting read....Thanks for the info

[sneakey pete]

Interested to note

"Timing was untouched for the duration of the testing"

an extra 15psi didn't make a huge difference either.

[Lithium]

Yeah I'm not too sold on the not touching timing thing for the comparisons thing - part of the point of changing parts is changing what the engine can do, tuning a car is what gets that potential out... there may (or of course may not - we can't know) be potential for the 3794R to make more power & torque as the timing maps would have been set using the 6766 seeing as it was the first turbo in the test.

In regards to the not much gain - not far under 10whp per psi when you are dealing with 40+psi is a pretty respectable gain on a 2litre!

One way or another, to me it appears that if we had compressor maps to refer to - the 3794 compressor map would look better suited to higher flowing lower boost engines while the PT6766 is more high boost biased - which is a suspicion I've had for a while, as with the fact that the two turbos would be VERY close.

[GTScotT]

cheers for posting, it turns out the 3794 is a much larger turbo than I expected. Ive been curious about their 3788 HTA for some time now, but dont think it will spool anywhere near like what I had imagined after seeing this.

[Lithium]

Their GT3786R would be a lot more responsive than the 3794R I'd say, probably still quite good power potential and probably roughly equivalent to the PT6266 CEA - so a different kind of beast. The 3794R is a large turbo, always was going to be quite laggy.

[rondofj]

Do people actually use these turbos on dailys - ie power/boost after 5500rpms aaarrgh........the US does have long straight roads though..

[Lithium]

Typically more of a drag turbo on EVOs, funnily enough - though don't let the scale caused by the huge power numbers fool you, I wouldn't say boost is "starting" at 5500rpm when both turbos are making >300awkw when they intersect the 5600rpm line. This is just a 2litre engine with porting and head work for HIGH rpm and it is making 180awkw on both turbos by around 5000rpm on a fairly low reading dyno. That isn't really messing around that badly all things considered, on a 3litre engine these things would be totally streetable.

[R31Nismoid]

Yeah as you've said they are just top end motor builds with huge boost in mind for outright top end. No doubt you could bring them on sooner if you built a motor accordingly and never planned to run more than 20-24psi type of thing.

Interesting results from the point of view that they are just so close, didn't expect that at all. Would be interesting to see them play with timing though as you said because @ lower boost levels you'd think more timing could've been plugged in etc. None the less a good read and differences @ various PSI levels etc.

[GeorgesR34]

fark. 55psi through a motor. That is crazy.

[wedge_r34gtr]

fark. 55psi through a motor. That is crazy.

i'd say thats absolute, not guage...so take ~14psi off those readings.

interesting results. thanks for sharing

[black bnr32]

here's a 2.9L BMW M52 at 'regular Joe' boost levels (18 psi?)

source: http://forums.bimmerforums.com/forum/showthread.php?t=1913480

T4 divided 1.00 a/r HTA 3794R DBB billet Turbo(SLOWER SPOOLING)

-VS-

T4 open .68 a/r 6776 DBB non-billet Turbo

Edited January 16, 2013 by black bnr32

[Lithium]

Hmmm another test where someone uses Precision T4 open turbos on a T4 open manifold then puts a competitor T4 divided turbo on the same manifold and it fails to perform as well as the Precisions, or as well as it normally would - what are odds?? I like to think that it is not deliberate, but either way that test doesn't really show anything useful in regards to the FP turbo. I'd hope there aren't too many people who'd put a twin scroll turbo on an open manifold hoping for it to perform as it should!

[PJ.]

Great read, thanks for posting. Amazing that they are flowing that much with that housing at high rpm too.

[Lithium]

Agreed - amazing stuff on both. Still only E70 too

Fairly sure if both turbos were used on their "biggest" options they'd be capable of more, but it seems that Boostin were trying to eliminate anything which the general populace would consider an unfair advantage which I reckon they did a good job of. If I were going full attack with the 3794R I'd probably considered the TiAL 1.03a/r housing, or the 1.32 T4 TS Precision housing. On E85+ the results would be mental too.

[PJ.]

The results given ethanol content doesn't completely shock me, the fact that they were still doing something at that boost level does. I'm going back to a 6766 later in the year, mine made 853hp atw on 42psi. Going off a 15% drivetrain loss that is 980hp at the engine, I can't see it making too much more power than that on my setup...might have to try again

[sky30]

Isnt drivetrain loss a set figure not a percentage?

A gearbox only takes xx amount of power to drive, this wont increase just because the engine makes more power.

[PJ.]

People have their own theories, I'm going off what Jim Berry uses here and I think in my case it's on par.

Edited January 16, 2013 by PJ.

[Lithium]

For what it's worth when I have done road tuning on cars I've usually been able to get a reasonable guess of what it is going to make on the dyno once timing is sorted just from injector duty cycle etc. It has tended to be fairly relative unless there is some issue, and there is no magic number I have to subtract after calculating it out despite the fuel usage being closest related to engine power while the dyno is obvious wheel hp - so I tend to feel if it isn't exactly percentage loss, that is still the best way of estimating. It is never going to be exact, naturally.

[sky30]

Id be interested to know what formula you use to get aprox power based on injecor duty and size if u will share?