Gas line pressure drops - why? - Aussie V8 | Holden - Ford

zoomstrange · 25-07-2008, 11:32 AM

G'day - got a technocarb not giving us the goods; while we are waiting for the national distributor to get his act together by sending the right bits for the thing, Guru Neville tested line pressure just after the safety lock (before converter) and found that line pressure was 400 - 420kpa until it was put under load (3-5000rpm) when pressure dropped to around 300kpa and stayed steady there. The line from the tank was set up for a stock 308, but I'm assured that the gas is under enough pressure anyway regardless of line diameter. We are looking for around 300 bhp which is a reason to suspect supply (mixture line goes right up at '45' degree angle and we see air / fuel 17:1 by 5000 revs from 11:1 @ 3000.
Venturi sizes are inch rear, 915 front - and we have been sent a couple of 915's to replace the bigger secondaries. This setup including the single converter supplied was supposed to flow 700 cfm (we reduced it from a possible 750 using the same converter).

The combo is a bored 355 stroker with dual plane harrop, VN heads that flow 502, large dia tri Y's into 4 resonators with the usual MSD etc. Stage 2 T700 turns a 3:36 salisbury. Should we be happy with 220 hp at the rear wheels? We think it's limp, but until air/fuel changes, we are a bit stuck. Perhaps the new secondaries are the answer. If they are, I know where to send the tuning bill accrued so far.

So, we are still wondering why the gas being consumed in the converter is sending a pressure drop back upstream - shouldn't it be shutting the door behind itself?

zoomstrange · 30-07-2008, 07:19 AM

Well, thanks everyone, you've been most kind.

zoomstrange · 30-07-2008, 07:20 AM

No, really, I couldn't have done it without you

zoomstrange · 30-07-2008, 07:21 AM

Here is a little token of our thanks - don't say it's too much - just get out there and enjoy yourselves on me

zoomstrange · 30-07-2008, 07:23 AM

What are you hanging around for, you crazy old gas helpin' Genius? I said go on - live it up while you can!

zoomstrange · 30-07-2008, 07:24 AM

Don't worry about me - my pleasure is in seeing you all having a good time - here, take another fifty.

zoomstrange · 30-07-2008, 07:26 AM

Hey - what are YOU doing, still hanging around? We'll clean this up, so don't worry about it.

zoomstrange · 30-07-2008, 07:27 AM

No, really, I insist - I've got all day, seeing the Sled isn't going anywhere.

zoomstrange · 30-07-2008, 07:29 AM

At least I didn't get flamed for having GRA problems. And that's a Good Thing.

zoomstrange · 30-07-2008, 07:31 AM

Should stop writing to myself.

zoomstrange · 30-07-2008, 07:34 AM

Yeah, well, you should also have gone with the Aussie technology, too, instead of sending good Australian dollars to Canada on the strength of all the advice you've seen in AussieV8 - so what if GRA doesn't flow as much as they say? At least it bloody WORKS.

zoomstrange · 30-07-2008, 07:38 AM

Hmm. That's a point. Probably could have afforded four GRA throttlebodies for what it's going to cost to sort out this technocarb. Lucky I'm fabulously wealthy, then.

zoomstrange · 30-07-2008, 07:40 AM

Should have stuck to the bikes. I'll just drain this last beer and take out the recycling. Now - where's that light switch?

greenhj · 30-07-2008, 07:43 AM

all you blokes should be ashamed of yourselves, fancy not jumping to help some anonymous fella who turns up and expects service with a smile and if it aint in 5 minutes you get your money back.

And you Zoom... You really need some professional help mate, what with the voices and all.

Heres a tip, Post in the right section!

Now wheres that magical padlock? Threads have been killed for FAR less!

WB5LTR · 30-07-2008, 11:23 AM

25-07-2008, 11:32 AM	#1 (permalink)
zoomstrange casual poster Trade Rating: (0) Join Date: Jul 2008 Location: Adelaide Ride: HX Hearse stroker Posts: 41	Gas line pressure drops - why? G'day - got a technocarb not giving us the goods; while we are waiting for the national distributor to get his act together by sending the right bits for the thing, Guru Neville tested line pressure just after the safety lock (before converter) and found that line pressure was 400 - 420kpa until it was put under load (3-5000rpm) when pressure dropped to around 300kpa and stayed steady there. The line from the tank was set up for a stock 308, but I'm assured that the gas is under enough pressure anyway regardless of line diameter. We are looking for around 300 bhp which is a reason to suspect supply (mixture line goes right up at '45' degree angle and we see air / fuel 17:1 by 5000 revs from 11:1 @ 3000. Venturi sizes are inch rear, 915 front - and we have been sent a couple of 915's to replace the bigger secondaries. This setup including the single converter supplied was supposed to flow 700 cfm (we reduced it from a possible 750 using the same converter). The combo is a bored 355 stroker with dual plane harrop, VN heads that flow 502, large dia tri Y's into 4 resonators with the usual MSD etc. Stage 2 T700 turns a 3:36 salisbury. Should we be happy with 220 hp at the rear wheels? We think it's limp, but until air/fuel changes, we are a bit stuck. Perhaps the new secondaries are the answer. If they are, I know where to send the tuning bill accrued so far. So, we are still wondering why the gas being consumed in the converter is sending a pressure drop back upstream - shouldn't it be shutting the door behind itself?

30-07-2008, 11:23 AM	#15 (permalink)
WB5LTR Do you ever leave? Trade Rating: (0) Join Date: Mar 2007 Location: Vic Ride: Holden WB ute, '05 WR450F Posts: 2,080	**** __________________

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30-07-2008, 07:19 AM	#2 (permalink)
zoomstrange casual poster Trade Rating: (0) Join Date: Jul 2008 Location: Adelaide Ride: HX Hearse stroker Posts: 41	Well, thanks everyone, you've been most kind.

30-07-2008, 07:20 AM	#3 (permalink)
zoomstrange casual poster Trade Rating: (0) Join Date: Jul 2008 Location: Adelaide Ride: HX Hearse stroker Posts: 41	No, really, I couldn't have done it without you

30-07-2008, 07:21 AM	#4 (permalink)
zoomstrange casual poster Trade Rating: (0) Join Date: Jul 2008 Location: Adelaide Ride: HX Hearse stroker Posts: 41	Here is a little token of our thanks - don't say it's too much - just get out there and enjoy yourselves on me

30-07-2008, 07:23 AM	#5 (permalink)
zoomstrange casual poster Trade Rating: (0) Join Date: Jul 2008 Location: Adelaide Ride: HX Hearse stroker Posts: 41	What are you hanging around for, you crazy old gas helpin' Genius? I said go on - live it up while you can!

30-07-2008, 07:24 AM	#6 (permalink)
zoomstrange casual poster Trade Rating: (0) Join Date: Jul 2008 Location: Adelaide Ride: HX Hearse stroker Posts: 41	Don't worry about me - my pleasure is in seeing you all having a good time - here, take another fifty.

30-07-2008, 07:26 AM	#7 (permalink)
zoomstrange casual poster Trade Rating: (0) Join Date: Jul 2008 Location: Adelaide Ride: HX Hearse stroker Posts: 41	Hey - what are YOU doing, still hanging around? We'll clean this up, so don't worry about it.

30-07-2008, 07:27 AM	#8 (permalink)
zoomstrange casual poster Trade Rating: (0) Join Date: Jul 2008 Location: Adelaide Ride: HX Hearse stroker Posts: 41	No, really, I insist - I've got all day, seeing the Sled isn't going anywhere.

30-07-2008, 07:29 AM	#9 (permalink)
zoomstrange casual poster Trade Rating: (0) Join Date: Jul 2008 Location: Adelaide Ride: HX Hearse stroker Posts: 41	At least I didn't get flamed for having GRA problems. And that's a Good Thing.

30-07-2008, 07:31 AM	#10 (permalink)
zoomstrange casual poster Trade Rating: (0) Join Date: Jul 2008 Location: Adelaide Ride: HX Hearse stroker Posts: 41	Should stop writing to myself.

30-07-2008, 07:34 AM	#11 (permalink)
zoomstrange casual poster Trade Rating: (0) Join Date: Jul 2008 Location: Adelaide Ride: HX Hearse stroker Posts: 41	Yeah, well, you should also have gone with the Aussie technology, too, instead of sending good Australian dollars to Canada on the strength of all the advice you've seen in AussieV8 - so what if GRA doesn't flow as much as they say? At least it bloody WORKS.

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30-07-2008, 07:38 AM	#12 (permalink)
zoomstrange casual poster Trade Rating: (0) Join Date: Jul 2008 Location: Adelaide Ride: HX Hearse stroker Posts: 41	Hmm. That's a point. Probably could have afforded four GRA throttlebodies for what it's going to cost to sort out this technocarb. Lucky I'm fabulously wealthy, then.

30-07-2008, 07:40 AM	#13 (permalink)
zoomstrange casual poster Trade Rating: (0) Join Date: Jul 2008 Location: Adelaide Ride: HX Hearse stroker Posts: 41	Should have stuck to the bikes. I'll just drain this last beer and take out the recycling. Now - where's that light switch?

30-07-2008, 07:43 AM	#14 (permalink)
greenhj not to be trusted Trade Rating: (0) Join Date: Jun 2006 Location: melbourne Ride: vz crewman, vs wag, the green one, EH prem soon. Posts: 1,857	all you blokes should be ashamed of yourselves, fancy not jumping to help some anonymous fella who turns up and expects service with a smile and if it aint in 5 minutes you get your money back. And you Zoom... You really need some professional help mate, what with the voices and all. Heres a tip, Post in the right section! Now wheres that magical padlock? Threads have been killed for FAR less!