This may interest some members,if I had some cash I'd consider bidding.

http://cgi.ebay.com.au/ws/eBayISAPI.dll ... B:TB6:AU:2

If i had an explorer manifold i would consider it as well. Looks like the lower section of the top half of an explorer has been jouned to a box, and the throttles look similar to the 6cylinder throttles. I feel that wiith such large throttles it would have an airspeed problemm and as such would loose a lot of bottom end torque

Brett

where does the EGR valve go, what about the throttle cable mount, I see more mods needed than they are saying.

The t/b cable looks like it go's across the front??? egr you'd just block off wouldn't you?
but yeah i'd say more mods needed to get the best out of it.

I would think you would loose a lot of bottom end torque, whats the point of 2 t/b if you only have 1 MAF, ECU would need a lot of tuning.

my thoughts exactly , Mass air flow metered by Maf versus inlet induction [pressure] in Plenum , could be a worry to tune..
I can see the point of it , but the distribution of 2 inlet flows ,
both would have to match the volume of air flow passing thru the Maf meter inlet . correct me if i'm wrong ...

This is for those wankers that want to say "Ive got twin throttle bodies"
I won't add anything else because the rest of you have already hit the nail.

Cheers,
Pete.

Ok guys just wanted to raise a few things

"I feel that wiith such large throttles it would have an airspeed problem and as such would loose a lot of bottom end torque"

I was always of the belief that torque was related to plenum size, runner length and runner volume, based on organ pipe theory (or as a Helmholtz resonator); which determines optimal induction tuning or “air rammingâ€￾ at a specific engine speed. Not throttle diameter. I mean how many guys here have upgraded to a 70mm from say a 65mm and experienced a loss in torque? Yet they gain improved throttle response because the amount of time that it takes to fill up the plenum is reduced. Plus an increase in power because of a lower pressure drop across the larger throttle body.

“my thoughts exactly , Mass air flow metered by Maf versus inlet induction [pressure] in Plenum , could be a worry to tune..
I can see the point of it, but the distribution of 2 inlet flows,
both would have to match the volume of air flow passing thru the Maf meter inlet . correct me if i'm wrong ...â€￾

Ok I’m not sure where you’ve come across this information but in regards to this manifold please check out this youtube clip http://www.youtube.com/watch?v=84j3V3NS-xQ and note the quality of the idle (please bear in mind that the cam is quite large!) and is running on a tune based on an explorer manifold. Though it’s not captured in this clip, the car did run amazingly well considering that it was not tuned for it yet! So it would be fair to say that it would run even better once it was. In regards to air speed across the throttle bodies and MAF (which is related to pressure drop) you can upgrade to a larger maf or run two (which you can!)


“I would think you would loose a lot of bottom end torque, whats the point of 2 t/b if you only have 1 MAF, ECU would need a lot of tuning.â€￾

A small amount of bottom end toque has been lost but only a small amount! This is because the effective runner length is now shorter by only 100mm. This is really isn’t a bad thing because it makes much more top end power. ECU doesn’t need a lot of tuning, as stated earlier the car runs extremely well even with the standard tune! As for running into a single maf well you can always put a 90mm if you wanted to better support the twins. However as an option, you can run twin induction pipes, filters and twin maf’s (the maf’s part wasn’t clearly stated in the ad though) to really let you Windsor breath


“This is for those wankers that want to say "Ive got twin throttle bodies
I won't add anything else because the rest of you have already hit the nail.

Cheers,
Pete.â€￾

Are you sure about this Peter? I ask this because the Holden Group A twin throttle manifold, which has well a truly proven its self time and time again, is STILL the best off the shelf manifold you can get for Holdens despite production of these things stopping around about 15 years ago!

Cheers
Steve

Looks like someone has a vested intrerest.

Go on & baffle them with science, but while you are at it, please explain the benefits of a twin throttle & single MAF arrangement (as on the youtube vid).

Apart from the single MAF being the most restrictive part before the lower manifold, wouldn't that slow the air speed since the same amount of air suddenly occupies a much larger space? Surely this loss of air speed will reduce throttle response & economy without improving power at all. Staging the throttles will reduce this effect down low, but the MAF (& lower manifold) will still be the limiter up top.

If you can't do that, explain how to make twin MAFS work without spending a fortune, especially if the throttles are staged (as per the above mentioned Walkinshaw manifold).

If a bigger MAF is the solution, why not a bigger single throttle? Probably because the Explorer/GT40 lower manifold is the limiting factor to all this anyway. Dont believe me? see here http://www.andersonfordmotorsport.com/media/intake1.htm Shortcut to page 3, second paragraph in the right column & note the systemax made more power & more torque than any of the boxed uppers on a GT40 lower. A Systemax (or similarly performing RPM2) wouldn't cost anywhere near the 2 grand this hunk of welded alloy is apparantly worth, whilst absolutely out performing it at all rpm points (even past the 6250rpm factory limiter).

I look foward to a response that we can all understand (& believe).

Last edited by sam12h on Sun Feb 11, 2007 11:27 am, edited 1 time in total.

Oh, & the reason for the success of the Walkinshaw? It wasn't the twin throttles. It is not separated into an upper & lower for starters & has ram tubes inside its box/plenum the correct length for a 5.0L spinning up to 7000rpm. If this boxed upper has ram tubes inside I'd be very surprised. I'd then wonder why it was mated to a GT40 lower manifold.

Twin throttles means nothing. Don't even try to compare this with a Walkinshaw. It's like comparing an old Camry with a new M3.

Certainly is, the bottom half of the explorer manifold really is quite crap and restricts airflow, so unless there had been a heap of port word done on the bottom half of the manifold, it really would be quite pointless.

The standard 5L does not really have enough puff to draw enough air through a MAF as big as 90mm either, I tried, with a GT40 manifold that is.

would be much better off getting a big Edelbrock or Trickflow and wacking a big single t/b on there.

Anyone find it strange that this item has been removed from eBay?

its been removed off ebay because i had a link to my (empty!) website. Will relist again tonight. No stress not going any where

questions will be answered in about 10 min...

“Looks like someone has a vested intrerested. â€￾

Yeah I do have a vested interest in sound engineering facts and not just hear say. Because at the end of the day you can only improve on designs, or anything in life in general, from an honest perspective. If the design is flawed, based on engineering facts, I don’t have a problem taking them on board to further improve products in future. It’s for this reason why I love forums and discussions in general

“Go on & baffle them with scienceâ€￾
You don’t think it’s a science then?

“please explain the benefits of a twin throttle & single MAF arrangement (as on the youtube vid)â€￾
Gains are still to be had even with running the stock sized maf. However to really make the most of this manifold you’d need say a 90mm maf, then the flow cross sectional area will be about the same of that of the twin 64mm throttles. Such that there isn’t any significant pressure drops in the induction system. Better yet though would be to use twin mafs (more on that in a moment). Please not that this car was setup with the standard maf because the car was going to be tuned at a later date however still needed his wheels back on the road.


“wouldn't that slow the air speed since the same amount of air suddenly occupies a much larger space? Surely this loss of air speed will reduce throttle response & economy without improving power at all. Staging the throttles will reduce this effect down low, but the MAF (& lower manifold) will still be the limiter up topâ€￾

The plenum isn’t as large as the photos portray it to be as shown by the pics below. Slow air speed before the runners is not a bad thing (unless they were a pair of carbs) because you will in fact get more air into the plenum (more air more=horsepower) per given period of time because of the lower pressure drop (resulting in better throttle response, because it gets more air sooner)). Which is why the vast majority of multi throttle setups, have a real sharp throttle response. So responsive in fact you’ll find that on some aftermarket setups, that the mechanical response time of the throttles are faster then that of a MAF or MAP sensor, that they have to use only a TPS to determine engine load. Which is crude but depending on the computer (like say a microtech for example) all that can be done. This is the main reason why some factory manifold using large throttles are staged, to water down throttle response, but with modern OE engines management systems isn’t a problem. Where fluid speed is really important is in the runners and injectors, because it determines when the optimal scavenging effect will take place (rpm band), plus maintain the suspension of fuel molecules in the air stream (instead of clumping together resulting in a poorer combustion).


“If you can't do that, explain how to make twin MAFS work without spending a fortune, especially if the throttles are staged (as per the above mentioned Walkinshaw manifoldâ€￾
Even if the throttle were staged which we won’t, because we want to maintain even air distribution across the entire RPM spectrum, it’s done using a balance pipe before the airflow meters and a voltage summation circuit for the maf’s. Of which the electronics have been done just need to fine tune its software before the fine tune. Cost wont be expensive, with filters balance pipe and “black boxâ€￾ around the $300 to $400 mark.


“If a bigger MAF is the solution, why not a bigger single throttle? Probably because the lower manifold is the limiting factor to all this anyway. Dont believe me? see here http://www.andersonfordmotorsport.com/media/intake1.htm Shortcut to page 3, second paragraph in the right column & note the systemax made more power & more torque than any of the boxed uppers on a GT40 lower. A Systemax (or similarly performing RPM2) wouldn't cost anywhere near the 2 grand this hunk of welded alloy is apparantly worth, whilst absolutely out performing it at all rpm points (even past the 6250rpm factory limiter).â€￾

Twin smaller throttles are better then a single large throttle, even if comparatively flow the same, because if the superior air distribution. A classic example is a prototyple trickflow manifold as shown here http://www.mustang50magazine.com/techar ... ndex5.html Great link btw, however it doesn’t explicitly say that the lower intake of the runners are a restriction. What they mention though is how poorly designed some “boxâ€￾ plenums are, by over shrouding the runners, and not runner diameter! This one on ebay is not like these as shown in the section view below. You’ll also find that the runner diameter is also similar to that of the Holden group a manifold. That 2 grand figure, has purely been put there to gauge market interest. Based on our findings the recommended retail cost will be only around $1200-$1300, which includes upper manifold, throttle bodies and you’re ready to bolt on! The only thing you need to so is to lengthen/change a couple of vacuum/water hoses bend one of the tabs on the coil pack bracket and your ready to rock and roll. Unlike many of the higher end after market manifolds which have hidden costs associated with them, such as the requirement of a new larger throttle body, bonnet/firewall mods, new fuel rails etc. So yeah this “hunk of welded alloyâ€￾ is clearly great value no matter which way you look at it! Plus backed up by local aftersales support.


“Oh, & the reason for the success of the Walkinshaw? It wasn't the twin throttles. It is not separated into an upper & lower for starters & has ram tubes inside its box/plenum the correct length for a 5.0L spinning up to 7000rpm. If this boxed upper has ram tubes inside I'd be very surprised. I'd then wonder why it was mated to a GT40 lower manifold.

Twin throttles means nothing. Don't even try to compare this with a Walkinshaw. It's like comparing an old Camry with a new M3.â€￾


Yes your right the group manifold isn’t sectioned such like the GT40 manifold, and has straighter runners that more directly aim at the inlet ports, which is what give it its power. Unlike majority of the Ford manifolds make a clumsy 180 degree turn, plus another 50 degree turn to finally get to the intake ports! Using this plenum however the airflow only has to make about a 50 degree bend to get into the runners (because of the lower manifold) .Unfortunately though, because the Windsor has a small valley its difficult (not impossible though, like v8 supercar units) do get a direct shot into the runners like the group a manifold, hence the reason majority of the aftermarket manifolds still have a bend in the lower section. Yes our manifold does have heavly bellmounthed runners as shown by the pics below. Please note that we could have made the bell mouthed runners sit proud of the base (machined press tool would have made a bell mouthed runner very quickly!!!) but to optimize space these have been integrated into the base. And if any says that they must sit proud in this configuration I’d love to know facts as to why, so I can incorporate it in future.

GT40 manifold isn’t as bad as people think it is, with results of similar sized runners performing extremely well in other applications which we’ve had the good fortune to experience (Holden group A for example many many more though!) as proven by the article you’ve posted. Which pointed towards poor plenum design rather then runner size with the box type manifolds. Anyways the design brief of this intake was not to make a v8 supercar manifold, but to come up with a very competitively priced and performing manifold and not a high end one (like v8 supercar spec), which we’ve clearly done. I know on face value it’s easy to put this manifold in the same category as the previous “boxâ€￾ manifolds of yesteryear, but based on what I’ve presented its unfair to do so. I’ve already said too much but I though I share some of the rational behind this design.

Please note that the pics below are of an earlier conceptual design (pre machining) to clearly show the bell mouthed runners (pre machining) and runners. So please appreciate that this design has been well though out and isn’t just an ad hoc arvo job, what some people may be thinking!