inlet restrictor(lpg mixer) removed with SFA performance gain

[deankdx]

Gday,
i just bypassed(temporarily removed for engineer clearances?) the gas mixer ring from just before the throttle body, at first after refitting the induct pipe i had a flat spot when reving in nuetral but computer must have fixed it.
let it idle for a few minutes while i opened the gates to go for a test drive and off i went, the result! NO NOTICABLE IMPROVEMENT, so my question is: is there a restriction in my exhaust? or will it improve more with some driving(computer retune?) or my seat of the pants DYNO needs calibrating or who gives a toss its probably the only falcon 1UZ in the world

the inside diameter is 40mm compared to 80mm of the outside diameter of the mixer, yep its small any opinions coments or suggestions or bagging appreciated

 

[Peewee]

I have always wondered if the stock 70mm throttle body was oversized for this motor.

This was proved when the addition of a 2nd 70mm throttle body provided SFA improvement to overall power.
Response was improved (as you should have found too), but power wasn't.

This would be purely because of the cams.

They are very conservative to keep the motor smooth.


That said, I am surprised that you didn't see an improvement at all.

 

[deankdx]

well its only the seat of the pants dyno not a propper dyno, i will have to test this at calder park sometime that will be my dyno, 1/4 mile at a time.
try to get there soon but SOOO lazy lately, maybe i'll be bothered and have time for this Friday and catch up with the blue HT ute? cant promise anything though(i get up at 4.30am so its hard to keep the energy required for a hectic arvo)

 

[SCV8]

I'd wait for two or three days of driving before you make any real judgements.
It takes a couple good driving cycles for the ecu to sort out any changes.
So your V8 is(was) breathing through a single 40mm opening?

 

[deankdx]

I'd wait for two or three days of driving before you make any real judgements.
It takes a couple good driving cycles for the ecu to sort out any changes.
So your V8 is(was) breathing through a single 40mm opening?

yeah i did think of this also, but i'm unsure if i have the wires going to correct places for closed loop tuning anyway(getting onto it next week) it WAS breathing through a 40mm restrictor.

 

[SCV8]

I recall, from many years ago, seeing a 440 Mopar with a tunnel ram, and two lpg valves, along with oxygen injection. They claimed it worked well.
That 40 mm restrictor is rather small, and these engines do seem to run pretty good in open loop.
The stock panel air filter is it's own restriction also, even with a K&N replacement it tends to destroy any tuning I do over 4,ooo rpm, finally went to a larger element.

 

[deankdx]

The stock panel air filter is it's own restriction also, even with a K&N replacement it tends to destroy any tuning I do over 4,ooo rpm, finally went to a larger element.

i am using a VN filter box and standard filter for space reasons with crazy bends in the ducting but still found no difference removing the restrictor.

 

[88Alltrac]

Flow

i am using a VN filter box and standard filter for space reasons with crazy bends in the ducting but still found no difference removing the restrictor.

Stock filter and "crazy bends" in the ducting seems to make airflow a bit shitty.
Any way to make them more straight and I would definitly suggest getting a BIG K&N!

The only thing that would be causing much of a restriction are any cats in the exhaust. And likely to be the muffler as well.The size of the headers, while they are not aimed at performance, should be able to flow well over 400hp worth of exhaust, while losing some power of course. (The heads need more work then anything on a 1uz.) Straight 2.5" pipe is supposed to be able to flow 550hp if not more. (Obviously on a turbo car we'd want larger though.) And 3" is supposed to be good till 900hp+ as far as backpressure is concerned. Keeping the velocity up to get the exhaust moving and pulling the next wave exhaust along is why exhaust size matters so much on an N/A car. Honestly, if an intake manifold is made correctly on a n/a engine, it can build positive pressure like a turbo would do. I've seen one tested that built 6psi! Just getting the harmonics correct to vibrate right along with every measurement on the manifold just right. For a regular person to do this is very tough though, these are pro race car companies hiring guys who think rocket science is cake. Race engines and builders is kinda of a cool subject to read up on, I think the big library near me had several GOOD books on it with pictures too. Gotta have pictures!