2" - 2.5" boost pipe kits, THE TEST

In a few minutes I will be dragging the Z out of the garage and heading to my fav tuning shop.

In the boot will be a full 2.5" boost pipe kit and Z1 intercoolers modified to 2.5"

Just so happens I have Z1 intercoolers on my car but at the stock 2" size.

The plan is to bolt the car up to the dyno and do a couple of power runs with the boost controller off & a couple with it on.
Then run the car at full throttle and held at certain RPM points to log a bunch of parameters, boost, torque, inlet temps, pressure at turbo, pressure at manifold etc.

Then we can disconnect the plumbing from the turbos and the throttles and set up the full 2.5" systems beside/infront of the car and repeat the tests.

We will do this back to back a couple of times to get an average for both set ups & finally have an accurate realistic result for what can actually be gained from these pipe kits.

I make no secret that I am extremely sceptical about the gains that have been/are claimed but I am also honest so what we get will be posted no mater the result. If I am wrong then some people will get a laugh - either way we will ALL have better test results than what we have had in the past

Stay tuned, dyno times starts at 12 today

EDIT: just to clarify this is a test for the BOOST pipe kits not the INLET pipe kits, some people have been confusing these lately

 

Bloody brilliant. This is the real data that is needed.

 

Are you also changing the throttlebodies ?

 

Well? results?
Im interested in this.
L8r
E

 

Product testing Glen?

Bahh... Another thing stolen from the Americians and replicated in other countries... You swine!

 

Keen...

 

Also keen

 

RESULTS:
(graphs to come later)

We hooked the car up to the Dynapack dyno and hooked up lambda sensors, turbo outlet boost pressure & manifold air pressure sensor.

To start the proceedings we kept things nice and simple, disconnected the boost controller so we had wastegate pressure and a nice stable boost curve with no electronic manipulation etc.

With a 274Kw @ the wheels peak power run we had 9.8PSI at the turbo outlet and 9.12PSI MAP at 7000RPM
A pressure drop of just 0.68PSI. Hardly anything to worry about but this could increase a lot with higher power/flow right???

At 344Kw @ the wheels peak power:
16.27PSI at the turbo & 15.30PSI MAP - a pressure drop of 0.97 PSI but this has to be much much more at higher power right?????

At 379Kw @ the wheels peak power:
21.48PSI at the turbo & 20.22PSI MAP - pressure drop of 1.26PSI

At 385Kw @ the wheels peak power:
22.09PSI at the turbo & 21PSI MAP = 1.09PSI drop


Now to fill in some gaps/questions people will have:

ALL runs showed the pressure drop was so small it could not be accurately measured until beyond ~4500RPM, the drop increased steadily up to 7000RPM (as flow increased so did the drop).

Inlet air temp stayed at around 40 degrees C fairly consistently when on boost.

Specs for the set up:

Z1 intercoolers, Z1 throttle bodies, Garrett GT2560R turbos, semi aggressive cams (long duration but mild lift), plenty of port work etc.


At this point is was VERY clear that we are dealing with a tiny pressure drop that is due more to the temp change from the intercoolers than it is from the pipes etc.
We were measuring the MAP also so that is AFTER the throttles, if we measured just prior to exclude them from the test the drop may have been lower.

So about here we all decided "yeah what ever" even if we were to have some miracle that made for zero pressure drop at all we were NOT going to see the results some people have claimed.
Even taking in to account that tiny tiny bit more flow would make for a tiny tiny bit more power from the exh and therefore more air going in etc ..

In the real world on a real car being driven by a real person you are NEVER going to see any benefit in going to 2.5" boost pipes on your Z32 - maybe if you are up over 700HP or something, maybe a tiny tiny gain but otherwise IMO you're dreaming.

If you flow test the bigger pipes and intercoolers they WILL flow more air no doubt about it but the point is the engine does NOT need that extra flow.

Looking at the numbers we got today we are getting ~100RWKW for every 10PSI boost, if by some miracle we reduced the pressure drop to half what it is now we might get 5Kw more power :rofl: I can think of better ways to spend my money!

The claims I've seen about faster spool - seriously doubt it as we didn't see any measurable pressure drops until beyond 4500RPM well maybe if you've sized your turbos wrong :rofl:

Anyway we tested and this is what we found, we never bothered to even fit the 2.5" kit as to us it was apparent this would be a waste of time :zlove:

 

did you use 2" throttle bodies for the 2" setup?
then swap to z1 throttle bodies with the 2.5" set up?


.

 

Nice results good to see someone doing all the tests! 385rwkw on 2560r turbos! I didn't think that power level was acheivable with those turbos.

Don't want to venture off topic (or PM me if you prefer)
What fuel, cams, (valves/port work) has been used and done to achieve those numbers?

Matt.

 

I think all these tests were done on OEM pipework with z1 throttle bodies Rob.

 

very nice work . it was good of you to do this

 

so wheres the 2.5" comparison?

I'm lost at what you are comparing to?

 

Yes we did all these tests on the stock pipes but Z1 throttles and Z1 intercoolers, I had intended to do back to back tests with the 2.5" kit but after we found the pressure drop to be so small we called it a day.

 

Hey Matt
Not too far off topic and actually reminded me of something else we found.

Stock fuel pumps are good for ~700HP some people have claimed.....
NO THEY ARE NOT.
We checked the fuel returning to the tank today and found at about 350KW the fuel pressure had dropped enough no fuel was returning to the tank.
At this stage the car was running out of fuel at anything beyond ~350KW - no more 385KW runs until a dual pump or similar set up installed

555cc nismo injectors and lots of port work, stock valves, self made down pipes, 2.5" exh system, stock accordion and turbo intake pipes.

Turbo intake pipes next to be tested - now these I can see an advantage as I'm sure I can hear the RHS turbo suffering at higher power. I'm not going to explain "suffering" as some people wont understand & I'm not looking for an argument :rofl:

 

So much for the 2.5 benefit claims (and they all go quiet)

Really good of you to do this, then post it - as it will save many from the sales pitches and traps and resulting $$$ losses

Simply put - three hoorays for mungyz!

 

That's a fair amount of power from those turbos, pump fuel or e85?

 

BP 98 pump fuel it will make more on Avgas I need to sort the fuel supply out though as apparently the Z32 community has been fed a bunch of BS on what the stock pumps will deliver

 

Hey Glenn
thanks for your dyno results and dont take this too personal
but
whats the purpose of this thread ?
I got excited when I saw the thread with 2" vs 2.5 TEST"


You do a couple runs on the dyno with 2" piping and 2.5" throttle bodies and claim "its apparent 2.5" piping IS A WASTE OF TIME".

If you want to discredit the US results (I would like to see someone else do this test ),then do a proper test !.

the real test is and always has been
FULL 2" SYSTEM
vs
FULL 2.5" SYSTEM
this would require an adjustment on AFR's in the midrange due to more volume of air