70mm Commodore Throttle Bodies!!!

[thehsvmanv6]

Hey there guys. A mate of mine recently suggested that I install a big-bore 70 mm throttle body on my Commodore. After looking further into it I have decided to go ahead with this mod. However on eBay they sell them for $200, so I've contacted a seller and he agreed and is willing to do a deal on these items if a group of buyers decided to go in together and buy these at a cheaper price.
hence I'm just throwing it out there, hoping maybe to get a group deal going on. So those of you interested, let me know by October 15th, and hopefully we can enjoy the benefits of this smart mod. I've included the following information from the site for additional information. Basically for V6, they offer 31% better efficiency, and for V8 there is a 16% increase. Cheers and all the best.

"Here we have for auction is a rebored VN-VR commodore / lexen V6 or V8 throttle body The standard V6 throttle body is 60mm and the V8 is 65mm This one is 70mm !!!! so it will let about 30% more air then standard V6. So more air = more power and you get a much improved throttle response!!! we also find a better fuel economy and these days that is a big plus. So it will bolt straight on to your V6 - V8 with no hassle at all but with the V8 you will need to change the throttle plate. It also comes with tested and cleaned throttle position sensor and the idle air control valve which are second hand but are in working order, it also comes with a new galvanised STEEL butterfly that is the strongest you can get and for lifetime lasting also to help against carbon build up and our throttle bodys have been polished inside for the best air flow you can get, all work has been carried out in a fully equiped workshop with all the right equipment to guarantee the right job,and if in anyway you are not happy with your item we are more then happy to replace your item as we expect everyone to be satisfied with there purchase. (please note that the price listed is only for a short time only) also if you are new to ebay you are more then welcome to bid as we all deserve a fair go. Thank you and happy bidding."

[blaze]

or u can just buy 1 trust me man this bloke is very good i got mine of him he is a top bloke and helps ya out real well Automan0_9 i think his name is but yeah very happy with my item

[stocky]

why bother? spend money on something more useful

[anton1o]

Somebody on this forum done a maths equation to prove 69mm-70mm is an extreme size for even a worked 6cyl.

[thehsvmanv6]

You know, I believe that this modification is a worthwhile one. But as most of you agree, $200 is abit of money, and for young blokes such as myself wanting to keep their cars going strong, I'll do anything to improve it provided its within budget. Being a student, money is already hard to come by, but that doesn't mean I have to stop enjoying working on my VP.

This forum has been set-up for those who are interested in undertaking this modification. If you are not, then unless you have useful information that can point us who are interested into a better direction, enough with the criticism already. Thank you.

[xcop5l]

70mm is not worth is as the inlet where the throttle body bolts onto is only 68mm
soo its just over kill.

[mouce]

Basically for V6, they offer 31% better efficiency, and for V8 there is a 16% increase.

Maybe I'm missing something here, but how do figure on getting 31% better effiency out of the six, with just an overbored t/b? For that to be the case, and assuming you're talking about fuel efficiency, that would mean that around town I could expect to get 7.2L/100km, and out on the open road I could expect to see somewhere around about 4-5L/100km.

I can't see how that's possible, given that the engine is still going to be revving at the same speeds. I understand the t/b well enough to understand that at lower throttle percentages the rate of change of the area of the opening as a function of theta (being the angle at which the throttle plate sits) is greater, thus allowing a free-er air flow at low %, but I still fail to see how you can get 31% better efficiency.

Anyone got an answer?

[1991_Vn2nV]

Maybe I'm missing something here, but how do figure on getting 31% better effiency out of the six, with just an overbored t/b? For that to be the case, and assuming you're talking about fuel efficiency, that would mean that around town I could expect to get 7.2L/100km, and out on the open road I could expect to see somewhere around about 4-5L/100km.

I can't see how that's possible, given that the engine is still going to be revving at the same speeds. I understand the t/b well enough to understand that at lower throttle percentages the rate of change of the area of the opening as a function of theta (being the angle at which the throttle plate sits) is greater, thus allowing a free-er air flow at low %, but I still fail to see how you can get 31% better efficiency.

Anyone got an answer?

I dont think efficiency refers to fuel efficiency...Although im not sure what it refers to...

Somebody on this forum done a maths equation to prove 69mm-70mm is an extreme size for even a worked 6cyl.

And I still dispute that equation. It should be done via the amount of air sucked in per intake rev, not per minute. The engine doesnt suck a constant flow of air. While the V6 may suck in x amount of air per minute, thats because it only sucks in air every second rev, but that wasnt taken into account. So using that equation its saying the V6 only sucks half the amount of air per rev that it really does... because its having to account for the exhaust rev as well.

[mark_1000]

I got one of these a few months back and had it put on my car this week. Until the ecu sorts itself out, or i get it retuned i wont be able to tell if its made any improvements, but at the moment the throttle is quite touchy, and it idles a little bit higher too. As far as i know, it isnt the best mod for bang for your buck, but as for simplicity, it is one of the easier mods, and it means i dont have to have my car off the road for very long in the meantime.

[ashzv6]

depends how much cheaper,
but i will probly be down for 1.
my only question is about the sensors,
are they all installed?
so you just need to connect it to the throttle elbow right?


and i think it actually means the airflow is 31%
better(less restrictive?) than the 60mm

[anton1o]

v8 65mm does a good enough job!

[mouce]

and i think it actually means the airflow is 31%
better(less restrictive?) than the 60mm

Even if that's the case, every simulation I've ever seen shows that the stock VN V6 motor doesn't max out the max flowrate of the stock t/b at WOT.

Sure at lower throttle percentages the response will feel more lively but there's no increase in max power.

[Boonz]

really it just means you dont have to fully open the throttle to let the same amount of air in as a stock T/B...
how come the TPS doesnt give an incorrect reading to the ecu as it thinks its letting in less air than it really is????

[pandaman]

really it just means you dont have to fully open the throttle to let the same amount of air in as a stock T/B...
how come the TPS doesnt give an incorrect reading to the ecu as it thinks its letting in less air than it really is????

Actually, doesn't matter too much really, the fuel maps specify an AFR versus MAP and RPM not a specific amount of fuel, the computer works out AFR's from the O2 sensor reading and supply's the appropriate amount of fuel.

[greenfoam]

The ecu only adjusts the fuel ratio from the O2 sensor when its at 14.7:1 on the fuel map anything other than that is a calculation based what the map sensor is reading, the rpm, the injector size the VE table and a few other things. Still the point is that the throttle body for a stock or bolt on V6 is plenty big enough allready. You only need a bigger one on a good 304 and even then it's not a big gain unless it's a pretty serious motor

[pandaman]

The ecu only adjusts the fuel ratio from the O2 sensor when its at 14.7:1 on the fuel map anything other than that is a calculation based what the map sensor is reading, the rpm, the injector size the VE table and a few other things. Still the point is that the throttle body for a stock or bolt on V6 is plenty big enough allready. You only need a bigger one on a good 304 and even then it's not a big gain unless it's a pretty serious motor

Ah right, thats making a lot more sense now, I was wondering how a narrow band 02 sensor could possibly work like that. But my point is that a larger throttle body wont stuff things up, it wont make the engine perform worse. I agree that a larger throttle body wont make much (if any) improvement, but there's no harm in chucking one on if future mods are planned. Apparently you can even gain a couple of kilowatts at the top end on a stock 5L by using a 70mm throttle body, but it's only top end that changes. You can simulate all you like but the real world results don't always match nicely.

[kasey375]

Hi. If any one want a 70mm throttle boddy i wold be getting one from here
http://cgi.ebay.com.au/VN-V6-V8-THRO...QQcmdZViewItem
These are very a very good throttle body and he will do them cheaper than any one else.

[greenfoam]

Ah right, thats making a lot more sense now, I was wondering how a narrow band 02 sensor could possibly work like that. But my point is that a larger throttle body wont stuff things up, it wont make the engine perform worse. I agree that a larger throttle body wont make much (if any) improvement, but there's no harm in chucking one on if future mods are planned. Apparently you can even gain a couple of kilowatts at the top end on a stock 5L by using a 70mm throttle body, but it's only top end that changes. You can simulate all you like but the real world results don't always match nicely.

Yeah you can gain a few kw on a stock 5 liter but not on a stock v6. But it makes sense you could gain 5 rwkw on v6 with a big cam and ported heads if you were going that far with the engine, weslyrpg tested his bolt on V6 back to back with the stock throttle body and a big one and made exactly the same power on both runs

[AlpineRaven]

Can it be done at home job? I have an lathe here and would it work?
Cheers
AP

[andrewownsavp]

be cheap and take the throttle body restricter out and money else where could be more useful

[Emackulation]

be cheap and take the throttle body restricter out and money else where could be more useful

I beleive your talking about the process of removing the Bellmouth from the plenum?

[AlpineRaven]

be cheap and take the throttle body restricter out and money else where could be more useful

Where excatly is throttle body restricter? - would it improve air flow?
Regards
AP

[1991_Vn2nV]

Between the plenum and the elbow that connects to the throtte body mate.

Its a peice of black plastic. Yes it will improve air flow.

[Morton]

Makes the old buick idle like a pregnant haddock, too. I love it