I've been thinking about making this thread for a few months. Finally bit the bullet here goes.

I am proposing 2 standard tests.

Test#1: 4th gear 1000rpm go wide open throttle instantly
Test#2: 3rd gear, stand on throttle at 2000, 3000 and 4000rpm


The Rules

#0 Twin Rotors only (12A and 13B)

#1 No data no post

Data constitutes data recorded by your engine management system or your data logger, not eyeballing a boost gauge, no data don't care sorry.

#2 4th gear @ 1000rpm, pin the throttle wide open on flat road. Aim for a test temperature between 15C - 30C (59F-86F)

#3.0 Supply all relevant test conditions!
#3.1 Altitude
#3.2 Engine Size and port job prefer general style/size of port
#3.3 Manifold design (single divided)
#3.4 Exhaust size muffler style and noise level, catalytic or not, screamer pipes or not
#3.5 Time since rebuild and miles/kms since rebuild
#3.6 EXACT turbo specification, compressor wheel inducer+exducer dimensions, both turbine wheel dimensions, turbine A/R
#3.7 Ball bearing or not
#3.8 Dump pipe size
#3.9 Vehicle weight
#3.10 Tyre Brand and Model (specify if they are street, performance, r compounds radials etc)
#3.11 Tyre Size (205 50 R15, 255 40 R17 etc etc)
#3.12 Diff ratio

Test #2 will be measuring boost rise shape when the driver goes from 10% throttle at the engine speeds listed to 100% throttle instantly.

The point is you measure the time from whatever the steady state was to 66% or 90% of the peak value manifold pressure when using metric units of BARs absolute, 66% is probably going to be more consistant.


I will supply my own data and I am hoping for data from the other single turbo guys, especially 13BT, 13BRE's and 13BREW's using GT35R and larger turbos.

 

Jobro, you are in winter....... It was 100*F (38*C) in New Orleans yesterday.
That would make my intake temp about 42-44*C.
Some of us will have to wait a few months to test!
Barry

 

Jobro,
How about comparisons of a 10 second pull from 3000 RPM with a trace showing spool?
With temps and boost showing on the log?

 

I agree that pulls from 1000rpm would be helpful. Many of the new turbo cars now hit full boost under 2000rpm.

 

62-1 .84 Ptrim BB
HKS Cast Manifold
Stock Port 13BREW
Open WG
2600-3800 rpm
-7psi - 16psi
ATS 91
CTS 183
4th gear
12 sec Trace

Thats the closest I have on laptop to what you are looking for.

I can probably run some of those scenarios.

 

Those are all great graphs. Now I can't find my own charts. I will have another look tomorrow they will be somewhere.

I suppose I could collate the raw data if everyone wanted to PM me for my email address and then email me the data.

I think we need to standardise the test to boost vs. rpm plot to 1000rpm if we can. To give you an idea my car makes 13psi @ 3000rpm under some conditions (not sure about during the standard test I'm proposing) when loaded up and I guess I want to see from other peoples results how much a larger turbo is going to loose out there.

If everyone does the 1000rpm wide open throttle test I can plot boost vs rpm for various turbos from say 1250rpm to as high as you are game to rev it and we will have a very balanced view of how big the 'torque/boost hole' is.

Barry does your car use a divided exhaust T4 turbo? What is it?

Sesshoumaru thanks for that result! Is your turbo turbonetics? Does it use the F165 turbine wheel? Got any pictures of it?

 

Raymond,
I have the usual 3000 rpm tests for my TO4S and TO4Z. (divided cast HKS)
You guys aren't worried about full throttle in 4th gear from 1000 rpm?
Seems like a lot of load in a range that is never used as such.
But I agree that it would show spool better... but possibly to the detriment of the engine.
Barry

 

Some updated logs -

It's a turbonetics without the F165 wheel.

Only the last 4k log showed a pull when I got my fuel and boost controller tuned (was out tuning).

It looks as though my AIT increase around 20 degrees.........

A couple things to keep in mind is injector staging and boost controllers.

I use Primary hold (primary injectors do not decrease when the secondaries come online). I've noticed I have positive pressure faster and you can't tell when you are in transition or boost.

Tweaking my boost controller I was able to alter my pressure rate increase a bit.

I would say 5-8psi is a good neutral reference point that would elimate most of those factors (especially people running off WG springs).

 

#3.0 Hot Humid Texas Summer Day, starting air temp was 35C. Third gear run from about 2500 rpm. Flat road, two people in car.
#3.1 Altitude = about +50 above sea level; Katy, Texas
#3.2 13B-REW stock intake ports with barley ported exhaus.t
#3.3 Manifold design, short T3 A-Spec kit.
#3.4 Exhaust: 3" DP and MP with Racing Beat dual tip catback
#3.5 Time since rebuild and miles/kms since rebuild, rebuilt in 1999 with 48,800 miles.
#3.6 EXACT turbo specification, Garrett GT35R
Compressor:
Wheel Inducer Diameter: 61.4mm
Wheel Exducer Diameter: 82.0mm, Trim: 56, A/R: 0.70
Turbine Specs:
Wheel Diameter: 68.0mm, Trim: 84, A/R 1.06
#3.7 Ball bearing
#3.8 Dump pipe size, about 2.25" back into DP.
#3.9 Vehicle weight about 2800 lbs R1 FD
#3.10 Yokohama AD08
#3.11 255/40-17
#3.12 dif ratio3.909

16 psi run.

In 4th or 5th (.86) gear, it will reach max boost around 3600 rpm.

 

Jobro I don't have any logs saved from that low of RPM, these are the lowest start points I have, engine is sitting on the bench at the moment. On the high way in 4th and 5th I see 15psi by 3500-to 3800 if I start from 2500, though I don't have a log of it. My computer crashed a few months ago and I lost a lot of stuff, these stayed for some reason??

1st pic- is 3rd gear from 2800rpm. target boost is 15psi.
2nd pic- is 2nd gear, from 2800rpm, then shifting into 3rd, 4th and 5th. Target boost is 18psi

3.0-These were done in June of 2011 so it was pretty warm out.
3.1- Florida, Right near da beach man
3.2- Cosmo irons, FD housing, and a Ported REW manifold
3.3-Its a 35r t-3 1.06 a-spec shorty,
3.4- 3inch exhaust.
3.5- About a year since last rebuild with 15,000 miles on it, very hard miles...
3.6-BB
3.7-Dumped straight off wastegate.
3.8-2800lbs
3.9-BFG g force sport
3.10-245/50/16
3.11-4.10

On the chart, the upper portion ( blue line) is Rpm (red line) is Knock. In the lower portion the Green line is Boost

 

Same car and info except:
30C air temp instead of 35C
16.5 psi instad of 16psi
4th gear instead of 3rd gear.

 

#3.0 Temp was 25-30C. Fourth or Fifth gear run from 2000 rpm. slight uphill road, two people in car.
#3.1 Altitude = sea level
#3.2 12A tall port street ported
#3.3 Manifold design, S5 pattern divided
#3.4 Exhaust: 3" DP single centre offset truck muffler
#3.5 Time since rebuild and miles/kms since rebuild, rebuilt in 2005 with 40000 miles.
#3.6 EXACT turbo specification, V-Trim Highflow
Compressor:
Wheel Inducer Diameter: ~55.0mm
Wheel Exducer Diameter: 70.0mm, Trim: 60, A/R: 0.60
Turbine Specs:
Wheel Diameter: major 63.75mm, minor 54.61mm Trim: ~73, A/R 1.0
#3.7 Journal bearing
#3.8 Dump pipe size, 3", open gates.
#3.9 Vehicle weight about 2700 lbs sa22c (RX7 gsl + 2 passengers)
#3.10 Toyo R888
#3.11 185-60-R13
#3.12 diff ratio 4.444

Also this is on summer mix pump E85


After looking at my data I can see that unless someone is posting up a really responsive setup even 2000rpm should be heaps to show the low RPM boost hole.

 

I notice the difference between your 2 plots and I have seen that exact same trend myself. On a really cold night I can get 13psi 0.9bar @ 3000 in the higher gears, but the plot I have shared doesn't show that because it was a hot day.



Thanks to everyone that has posted so far. I just had a bit more of a look through the plots they are all great. There is a lot of information in here now.

If we could get a GT42 frame turbo in here that would be great.

 

Jobo, how much boost are you running. Your kpa scaling in your chart seems off, it starts at 50 kpa, 7 psi, at no throttle???

Here is a log I found in 5th gear, its a totally different story than 2nd and 3rd. I start at 3300 rpm and by 3656rpm I have 1.00 bar. So in 5th I only need 300rpm to go from full vacum to 1 bar of boost in 5th. It was cold out though, winter of 2010.

Exact turbo spec, 61.4mm inducer 82mm exducer, 68mm turbine. 84 trim 1.06 a/r

 

I'm using kPA absolute. Really everyone in the turbocharged and supercharged world should be talking in kPA absolute. Base air pressure where I am is close enough 101.3kpa.

So generally 0-100kpa = vacuum to 0psi

100kpa through 200kpa = 0psi through 14.5psi

1kpa=0.145psi

That plot was with a 1.3 bar spring set in the wastegates on a reasonably hot day.