1G-GTE head flow rate?

[hypo23]

i have a custom plenum chamber on standard runners, with the throttle body at the front of the plenum, ive blown three motors as a result of one and six running too lean, manifold has been sent to andrew for power porting, when i get it back in about 3 weeks ill post before and after flow rates, also running no tvis as that seems too be such a hot topic at the moment, i completely removed it and used shorter studs to bolt the manifold back on.

im in the process of buiding a motor and tim from performance wholesalers has been a great help with his knowledge of 1gs, and getting aftermarket parts for them, they have trialled a lot of different set ups for theirs 1gs and know their shit, its a pity people like kyle (6boost) and tim dont come here anymore as there knowledge would go a long way

anyway ill start a new thread and post results as i get them, hopeing to get the carready for dubbo fingers crossed.

[Lambolica]

That would be great if you could post those figures.

Does anyone knoe the cost to get the flow checked?

[Fattony]

I wouldnt go to the time and effort to add a static butterfly in the TVIS just to even out flow, but i have removed teh system all toghther as you are giving the whole manifold a increase in flow, and as i have said all castings are different, hence is why you would want to send a manifold to andrew to be power ported so he can bench it and get the flow out of the manifolds even with his extrude honeing process.

[JustCallMeOrlando]

Okay, this could seem like an entirely bodgy idea, but humour me. Say the manifold was flow tested, and found to be 20cfm more air on 1 and 6, 10cfm from the TVIS having no rod through it, 10cfm from the runners themselves.
If we remedy the TVIS by tapping and inserting a bolt the same diameter as the rod, for those of us how aren't keen to spend the money power porting, would it be silly to suggest we drill and tap the same size bolt in the runner itself for the same effect?

[JustCallMeOrlando]

I wouldnt go to the time and effort to add a static butterfly in the TVIS just to even out flow

After looking at the TVIS plate Lambolica posted in the other thread, it's not a butterfly that has to be fabbed, it's just a bolt that needs to be inserted to make up for the lack of the actuator rod in the two end runners.

[Lambolica]

Yeah but that works well if you are going to do that sort of work.

In my case a stock engine the TVIS helps with the bottom end and the 1G's need all the help they can get.

For the sake of about $10 and few hours work to place a shaft in the end port to level the flow of the TVIS vs $660 to get the manifold done with no TVIS I know what I'd prefer.

And I think you would need bigger cams to get more flow at lower revs to make up for the loss of the TVIS plate.

[Lambolica]

Okay, this could seem like an entirely bodgy idea, but humour me. Say the manifold was flow tested, and found to be 20cfm more air on 1 and 6, 10cfm from the TVIS having no rod through it, 10cfm from the runners themselves.
If we remedy the TVIS by tapping and inserting a bolt the same diameter as the rod, for those of us how aren't keen to spend the money power porting, would it be silly to suggest we drill and tap the same size bolt in the runner itself for the same effect?

Or calculate 1 larger pin for the TVIS plate to kill 2 birds with 1 stone. That is where the info from the other thread is going.

[JustCallMeOrlando]

Hey, the lazy simple approach works fine Mind you, I doubt it would have to be a whole lot bigger.

[Lambolica]

No it wouldn't... numbers seem to indicate 5 - 5.5mm vs the standard ~4mm.

As well as this adding some resin to the butterflys to smooth air flow over them appears to significantly impact the turbulance created behind them. Like an aerofoil if you will.

[JustCallMeOrlando]

Hey, that's not such a silly idea with the resin...the devil really is in the details.

[mic*]

The oversize shaft is a cracker idea i think since flow reduction doesnt matter.

As stated, about 5mm instead of 4mm should do.

X-sectional area x C = Flow^2

Roughly calculated the 1mm extra dia = 20mm^2 X-section reduction and will acheive slightly more than the 10CFM flow reduction required.

Explain to me the resin idea tho? When closed, i would think the butterflies would neatly seal the TVIS runners so we cannot be talkin bout resin on the very edge, or we could not get the butterfly to close properly. And in cross section the butterfly already looks pretty flat - ie it does not have bulge where the shaft runs through - so what are we talkin about exactly? If we make it more areofoil shaped it will impede on the X-sectional area and further reduce flow.

[mic*]

Or do you just mean a fine layer all over to kinda glaze it?

[Lambolica]

The photo doesn't show it but the shaft runs accross the back of the butterfly and is bolted to the shaft

......O....... < like that

it is a farly nasty in terms of flow restriction.

[mic*]

Ah ha.

yeah resin it up for aerodynamics...

..../O\..... < like that, but moreso... i know what ya mean.

I still say wholeheartedly that it would be a (more complex but) much better concept if we had the whole thing at the start of the runners.

This is particularily when the butterflies are closed, but even when the butterflies are open, if the air still had a smooth passage of runner - say 20cm worth, after the butterfly, the turbulence would smooth out by the valve.

[Lambolica]

yeah but to run it at the top you would still need a butterfly at the bottom to stop pressure going back up the blocked runner.

there might be questions of engine response if you run it too far away however I am not good with that.

Edit.... And yes you are correct with the resin on the butterfly but moreso. No thicker, just a cleaner line.