so has anyone actually made 500bhp from a v12 pre.he
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From: new york
Went down the intake root 25+ years ago. At that time the Group A manifolds where unobtainable and indeed TWR / Jaguar denied their very existence. Got ali tubing bent up to do a cross ram system and replaced the dissy with the latest valley cover and coil packs. found that tigging in the pipes to flanges caused distortion to the angle and that it was very hard to get all around the flanges. Not just that the diameter of the pipes and their angle meant that the A and B bank would be inseparable, the finger of one side going though the fingers ofg the other. The piping was so very tight that when the warping occurred, even if small, the whole thing was a mess with different part interfering with others, I gave up. but do believe a good welder could do it (but you better not be paying him an hourly rate!
Yet this wouldnt be the total answer! You will still have unbalanced flow leading to inablilty to match all cylinders, always happens. Even Scott and TWR never got it all right with the Group A / std manifolds.
Jaguar say the idea of different length runners is to widen the power band, seems reasonable , as in a reasonable fudge. The truth is likely to be because it was easier, as simple as that. It was sill a reasonable effort for the time though and remember that ECU development had only just started and was totally incapable of running different cylinder advance or fueling. Sequential was rare and complicated, there were no after market ECU's and the biggest problem was getting enough sparks through a coil for a V12. Ferrari gave up and used 2 x 6 cylinder systems which works unless you link them, then they fight for control, literally.
Now you all have it easy.
If you want/ desire equal flow then get a manifold and flow it. Hog it out with die grinders and flap wheels but work on the poorer flowing ports 1st and only bring the others upto what the worst flow. Lots of time needed and lots of regular checks on a flow bench. But it can be done. Different sized washers on a stick give you the clue as to where the meat has to be removed. If you go through a std manifold on the underside you can tig a plate over the hole or use ceramic sealer. If you do a few of these manifolds you will get better and wont go through again.
So yes it can be done, and this will allow you to maximize the package.
AJ6 sent me their prototype long runner manifold, It was heavy (steel) and looked a bit ugly all tigged up. it flowed well but was crude, They made maybe 12 sets later and they were tidied up a lot. Not cheap but they did the job. Importantly for me they were not factory and got banned for my form of racing.
Better was the Broadspeed manifolds, but you will be lucky to find these nowadays. Made the inlet stubbs from ali thick wall tube and had a massive reamer cut to open the tubes at 2 or 3 degrees over their length The tubes were highly polished and oiled s that the wonderful trumpets were a push fit on top with a viton seal. All the cast and machined trumpets fitted internally to the twin throttle plenums with 4 10/32 screws so that you could line everything up perfectly. The plenum had a top and bottom joined on a flange with loads of 10/32 screws. The 2 x throttle bodies were std. I ran this on a metering unit to start with but ended up welding 'blimps' into the inlet stubs and using pre HE green injectors in the end. You could simply pull the top off the system if you needed access and I found a need to retain the top under racing as you could pop it off (and thereby end your race) on backfire on the over run going into paddock bend.
So now you know how to do it go forth and lets see who actually does it. I wont be holding my breath.
Yet this wouldnt be the total answer! You will still have unbalanced flow leading to inablilty to match all cylinders, always happens. Even Scott and TWR never got it all right with the Group A / std manifolds.
Jaguar say the idea of different length runners is to widen the power band, seems reasonable , as in a reasonable fudge. The truth is likely to be because it was easier, as simple as that. It was sill a reasonable effort for the time though and remember that ECU development had only just started and was totally incapable of running different cylinder advance or fueling. Sequential was rare and complicated, there were no after market ECU's and the biggest problem was getting enough sparks through a coil for a V12. Ferrari gave up and used 2 x 6 cylinder systems which works unless you link them, then they fight for control, literally.
Now you all have it easy.
If you want/ desire equal flow then get a manifold and flow it. Hog it out with die grinders and flap wheels but work on the poorer flowing ports 1st and only bring the others upto what the worst flow. Lots of time needed and lots of regular checks on a flow bench. But it can be done. Different sized washers on a stick give you the clue as to where the meat has to be removed. If you go through a std manifold on the underside you can tig a plate over the hole or use ceramic sealer. If you do a few of these manifolds you will get better and wont go through again.
So yes it can be done, and this will allow you to maximize the package.
AJ6 sent me their prototype long runner manifold, It was heavy (steel) and looked a bit ugly all tigged up. it flowed well but was crude, They made maybe 12 sets later and they were tidied up a lot. Not cheap but they did the job. Importantly for me they were not factory and got banned for my form of racing.
Better was the Broadspeed manifolds, but you will be lucky to find these nowadays. Made the inlet stubbs from ali thick wall tube and had a massive reamer cut to open the tubes at 2 or 3 degrees over their length The tubes were highly polished and oiled s that the wonderful trumpets were a push fit on top with a viton seal. All the cast and machined trumpets fitted internally to the twin throttle plenums with 4 10/32 screws so that you could line everything up perfectly. The plenum had a top and bottom joined on a flange with loads of 10/32 screws. The 2 x throttle bodies were std. I ran this on a metering unit to start with but ended up welding 'blimps' into the inlet stubs and using pre HE green injectors in the end. You could simply pull the top off the system if you needed access and I found a need to retain the top under racing as you could pop it off (and thereby end your race) on backfire on the over run going into paddock bend.
So now you know how to do it go forth and lets see who actually does it. I wont be holding my breath.
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Joined: Dec 2013
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From: Albemarle NC USA
Hi Cal,
I was going back over this site, to finish it up and saw the posts on the intakes people have worked on.
There's a ton of discussion on what would be better, good, and the best, but I'll not go there as every engine build/combination is a bit different and there seems to be a good variety of them in the V12 series and here on the forums.
I didn't really want to start posting on another forum but will with a few shots of a set of intakes I made several years ago for the Lamborghini V12 in my car and it was sort of a stone age system just to see how it worked, which was a great improvement on the 6 40dcoe's.
It was originally a mechanical system I built but converted it to EFI
Also a few shots of a Chrysler Hemi system I built years ago, that took a few weeks, and is another one-off unit.
It was with one of my more primitive EFI setups, and they are different now that I have much better injectors to work with.
If anyone wants to comment on it please use the '86 V12 EFI 8 stack forum to make it easier for me as I have limited time for the 'fun stuff' here.
I was going back over this site, to finish it up and saw the posts on the intakes people have worked on.
There's a ton of discussion on what would be better, good, and the best, but I'll not go there as every engine build/combination is a bit different and there seems to be a good variety of them in the V12 series and here on the forums.
I didn't really want to start posting on another forum but will with a few shots of a set of intakes I made several years ago for the Lamborghini V12 in my car and it was sort of a stone age system just to see how it worked, which was a great improvement on the 6 40dcoe's.
It was originally a mechanical system I built but converted it to EFI
Also a few shots of a Chrysler Hemi system I built years ago, that took a few weeks, and is another one-off unit.
It was with one of my more primitive EFI setups, and they are different now that I have much better injectors to work with.
If anyone wants to comment on it please use the '86 V12 EFI 8 stack forum to make it easier for me as I have limited time for the 'fun stuff' here.
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From: new york
I went and rebuilt and powdercoated the entire front suspension so that held up the engine work a lot.
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I was debating using steel on.the manifolds, the plenums will be bolted on, so I can put trumpets on the inside.
what would be any drawbacks to making the intake from steel as opposed to aluminum?
what would be any drawbacks to making the intake from steel as opposed to aluminum?
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From: north east AMERICA
I would go for alumnium likely too shave off a pound or two from the stock setup. Unless you make a set of shorties with velocity stacks in that case steel would be my route. Steel is more forgiving for fabricating sometimes
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From: UK
The inlet stubbs have flanges and go straight up. the plenums have a top and a bottom part, the bottom has 6 holes to take the subs + a little more to allow good alignment. The cast bell mouths (velocity stacks) are beautifully machined to give full 180 degree edges and push onto stacks they seal with a viton 'o' ring in the middle of the slide fit joint. the stacks fitt to the bottom section of the plenum with 4 x 10/32 screws fitted from the underside of the plenum and equally spaced at 90 degrees around the bottom of each stack. Looks like the very best of F1 intakes available at he time. The top section of the plenum functions simply as a lid, it is located with loads of 10/32 screws on the cast lip around the edges, The parts are all none sided, the cast lugs for the throttle cable are simply cut off on the one side and left on the other. If you look carefully you will see a metal square in the center of the 2 sides. This locks the 2 plenums together so each side dosent drop (remember they are just an interference fit on viton 'o' rings) there is a hole in the center of this plate which takes a bolt or peg which is mounted at the bottom on 4 central main studs, this peg either has a nut or a clip to retain the plenums set up in place ie so it doesnt pop of like I found happened on a backfire.
The injection is Lucas metering unit. Designed by a guy called Bob Blerton. Bob's thought process was just simply somewhere else on this gear. Took me 2 weeks with the unit in front of me to see how it worked and many months after that to appreciate how well it worked. Simpler versions of this unit were used in F1 for years and at Le Mans until about 1988. As good as any EFI on full throttle and better / more reliable than most. But a precision instrument costing lots to produce. The tolerances where so fine that on a cold day you needed to pour a kettle of water over the metering unit and wait 5 minutes for the internal components to expand deferentially (different metals with different co efficient s of expansion) Then manualy turn the start cam mount before turning over the engine. Dont do this and the belt could strip as the unit would be too tight to turn. The injection was metered, sequential and timed ! its downfall was cost of production, no cut on the over run and a total inability of 'mechanics' to understand and service it, look at what happened with the simpler Triumph 2.5 PI production unit.
Just a final note, the Broadspeed heads were special castings. The valves were moved to allow for larger inlets ie inlet slightly over to the center and exhaust away from the center (to allow for the inlet). The inlet port was also moved over to match with some of the steel stubs going into the heads on a taper to stop the problems of breaking through when enlarging and offsetting the inlet port. The exhaust was in the same place.
So back in the mid 70's Ralph Broads team managed 600bhp from a 5.3 (actually 5.4 from +60 as allowed by the regs) with mechanical Lucas injection. Std crank and std rods all be it with better bolts.
There is / was a firm in Belgium trying to repro these inlets but without originals (on the original cars or in my garage) they were struggling to work it all out. I'll let you chaps do the searches to find it.
Then there was that mag Broadspeed double sump pan with cast in oil ways, took me a month to work that baby out pouring water through it and fitting 2 std blow off valves, it was something else but is totally another story.....
The injection is Lucas metering unit. Designed by a guy called Bob Blerton. Bob's thought process was just simply somewhere else on this gear. Took me 2 weeks with the unit in front of me to see how it worked and many months after that to appreciate how well it worked. Simpler versions of this unit were used in F1 for years and at Le Mans until about 1988. As good as any EFI on full throttle and better / more reliable than most. But a precision instrument costing lots to produce. The tolerances where so fine that on a cold day you needed to pour a kettle of water over the metering unit and wait 5 minutes for the internal components to expand deferentially (different metals with different co efficient s of expansion) Then manualy turn the start cam mount before turning over the engine. Dont do this and the belt could strip as the unit would be too tight to turn. The injection was metered, sequential and timed ! its downfall was cost of production, no cut on the over run and a total inability of 'mechanics' to understand and service it, look at what happened with the simpler Triumph 2.5 PI production unit.
Just a final note, the Broadspeed heads were special castings. The valves were moved to allow for larger inlets ie inlet slightly over to the center and exhaust away from the center (to allow for the inlet). The inlet port was also moved over to match with some of the steel stubs going into the heads on a taper to stop the problems of breaking through when enlarging and offsetting the inlet port. The exhaust was in the same place.
So back in the mid 70's Ralph Broads team managed 600bhp from a 5.3 (actually 5.4 from +60 as allowed by the regs) with mechanical Lucas injection. Std crank and std rods all be it with better bolts.
There is / was a firm in Belgium trying to repro these inlets but without originals (on the original cars or in my garage) they were struggling to work it all out. I'll let you chaps do the searches to find it.
Then there was that mag Broadspeed double sump pan with cast in oil ways, took me a month to work that baby out pouring water through it and fitting 2 std blow off valves, it was something else but is totally another story.....
Last edited by xjr5006; Dec 24, 2013 at 08:11 AM.
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From: Austin tx and Daytona FL.
wow,, that Broadspeed setup would keep one busy if it all came in pieces, and then installing it!
and a complete tuning would be interesting ,to say the least!
i suppose back in the day its all they had to work with!
my 1st intro to FI was my 1957 fuelie vette, no one around the Boston Mass. area would touch it, so being how i am, i jumped in,feet 1st,and a$s over bandbox!
well after much screwing around didnt improve the factory GM performance at all, it made good midrange torque(over twin 4 barrels), and better MPG, BUT the twin 4s would out run the FI on the top end, (AIR FLOW).
then next yr ,1958, installed a Hilborn mechanical FI system, it took some time, but in the end it was very fast,good torque and nothing came close on top, (terrible MPG).
that Duntov cam, and factory FI heads , were ahead of its time, little old 283 could wind past 8000rpm ,no sweat!
but times have changed, and turbo engines rule, when it comes to performance and MPG, plus smooth drivability!
and i do have a sweet spot for diesel engines,especially for a full size street car!
and a complete tuning would be interesting ,to say the least!
i suppose back in the day its all they had to work with!
my 1st intro to FI was my 1957 fuelie vette, no one around the Boston Mass. area would touch it, so being how i am, i jumped in,feet 1st,and a$s over bandbox!
well after much screwing around didnt improve the factory GM performance at all, it made good midrange torque(over twin 4 barrels), and better MPG, BUT the twin 4s would out run the FI on the top end, (AIR FLOW).
then next yr ,1958, installed a Hilborn mechanical FI system, it took some time, but in the end it was very fast,good torque and nothing came close on top, (terrible MPG).
that Duntov cam, and factory FI heads , were ahead of its time, little old 283 could wind past 8000rpm ,no sweat!
but times have changed, and turbo engines rule, when it comes to performance and MPG, plus smooth drivability!
and i do have a sweet spot for diesel engines,especially for a full size street car!
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Joined: May 2013
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From: A.C.T
Wow this definitely has being a learning curve for me, some of you gents have just about seen it all, what a great knowledge base to have.
If I want to hone the original plenum, is there a way doing it from the head side only. Or is there a special hone that you can use without cutting the unit and welding it back together.
If I want to hone the original plenum, is there a way doing it from the head side only. Or is there a special hone that you can use without cutting the unit and welding it back together.
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Joined: Dec 2013
Posts: 40
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From: Albemarle NC USA
Hi,
I have to say the Broadspeed system was really done right.
And it looks simple.
Things like that are deceiving in that way.
It is the other end of the spectrum from the second picture.
I guess that answers the question of the 500 hp, but not sure if it was naturally aspirated or not from the pic.
It's a perfect setup for pressurizing.
I have to say the Broadspeed system was really done right.
And it looks simple.
Things like that are deceiving in that way.
It is the other end of the spectrum from the second picture.
I guess that answers the question of the 500 hp, but not sure if it was naturally aspirated or not from the pic.
It's a perfect setup for pressurizing.
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Posts: 183
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From: UK
Wow this definitely has being a learning curve for me, some of you gents have just about seen it all, what a great knowledge base to have.
If I want to hone the original plenum, is there a way doing it from the head side only. Or is there a special hone that you can use without cutting the unit and welding it back together.
If I want to hone the original plenum, is there a way doing it from the head side only. Or is there a special hone that you can use without cutting the unit and welding it back together.
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Joined: May 2013
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From: A.C.T
You can only do so much from one side, I band sawed the plenums to get full access and used the 3 bolt end plates to bolt and locate the cut off section afterwards, never used to weld them just used grey sikafllex, never had a problem. I thought thiis was the easy way and would allow reworking if necessary (never did need to) I was also worried about warpage from earlier experiences but maybe bolting the inlet tight to a head during welding would prevent this.
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One thing I do like that they make are the extractors but the price is very heavy and I not justified.
Jaguar Home Page
As I stated before Im on a fact finding mission at the moment, next year first thing is to get my big Bridgeport mill setup and converted to NC, then I'll have the Lot NC router , lathe and mill, I have the two complete motor's here I can just simply take my time and try and work something out. Cant really see fabbing a Plenum as a big deal Ive cut some plates out on the router already for others rebuilding LS motors wanting to do their own thing, they worked ok.
One thing I believe we really have to look at in this quest for the almighty 500hp is the ECU, we really need to go Coil packs and better injection if we are to stand a chance.
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xjr5006:
The two pix that Warjon posted look to be the same type of setup, it is just that the intake horns shown in the second pix are internal to the boxes shown in the first pix. Do I have this correct? I surmise this based on your description of how the trumpets are designed.
It appears that the Broadspeed intake uses, per bank, two individual plenums that contain three intake trumpets each, and these are both coupled to a single, large plenum via individual throttles. The large plenum is then fed from a 'cold air' source.
So I see several opportunities for tuning, inasmuch as the two smaller plenums have a resonant property, as does the single large plenum. The two feeds from the large plenum to the two smaller plenums should also have some sort of resonant characteristic. And of course, the trumpets themselves have their own resonant characteristic. So tuning looks to be the interplay of all these items: volumes, lengths, and so on.
The thing that strikes me most about this setup is that the interactions of one set of three cylinders seem to be somewhat isolated from the effects of the other set, concentrated in the behavior of the single large plenum.
Am I thinking about this the right way?
-M
The two pix that Warjon posted look to be the same type of setup, it is just that the intake horns shown in the second pix are internal to the boxes shown in the first pix. Do I have this correct? I surmise this based on your description of how the trumpets are designed.
It appears that the Broadspeed intake uses, per bank, two individual plenums that contain three intake trumpets each, and these are both coupled to a single, large plenum via individual throttles. The large plenum is then fed from a 'cold air' source.
So I see several opportunities for tuning, inasmuch as the two smaller plenums have a resonant property, as does the single large plenum. The two feeds from the large plenum to the two smaller plenums should also have some sort of resonant characteristic. And of course, the trumpets themselves have their own resonant characteristic. So tuning looks to be the interplay of all these items: volumes, lengths, and so on.
The thing that strikes me most about this setup is that the interactions of one set of three cylinders seem to be somewhat isolated from the effects of the other set, concentrated in the behavior of the single large plenum.
Am I thinking about this the right way?
-M
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From: new york
Yes I can see what you mean makes me think with all the trouble we go to to modify the original it would be half the work and time to just fab something new and be done with it! I looked at these guys and they seem to of honed from one side only unless they cast there own stuff? but doubt that.
Jaguar Home Page
One thing I do like that they make are the extractors but the price is very heavy and I not justified.
Jaguar Home Page
As I stated before Im on a fact finding mission at the moment, next year first thing is to get my big Bridgeport mill setup and converted to NC, then I'll have the Lot NC router , lathe and mill, I have the two complete motor's here I can just simply take my time and try and work something out. Cant really see fabbing a Plenum as a big deal Ive cut some plates out on the router already for others rebuilding LS motors wanting to do their own thing, they worked ok.
One thing I believe we really have to look at in this quest for the almighty 500hp is the ECU, we really need to go Coil packs and better injection if we are to stand a chance.
Jaguar Home Page
One thing I do like that they make are the extractors but the price is very heavy and I not justified.
Jaguar Home Page
As I stated before Im on a fact finding mission at the moment, next year first thing is to get my big Bridgeport mill setup and converted to NC, then I'll have the Lot NC router , lathe and mill, I have the two complete motor's here I can just simply take my time and try and work something out. Cant really see fabbing a Plenum as a big deal Ive cut some plates out on the router already for others rebuilding LS motors wanting to do their own thing, they worked ok.
One thing I believe we really have to look at in this quest for the almighty 500hp is the ECU, we really need to go Coil packs and better injection if we are to stand a chance.
I mostly need help making the bottom flange that will house the Injectors because I need someond with a 4 axis mill
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From: Vic Australia
Group A manifolds are not very useful on a road car unless you want make power above 6500rpm and lose power in the 3000-4000rpm range.
There are many Intake Manifold calculators on the net and running the numbers (depending on where you want the max torque) has the runners around 70-80cm long (3200-3800rpm) (remember this also includes the port in the head) and 3cm in diameter.
There are many Intake Manifold calculators on the net and running the numbers (depending on where you want the max torque) has the runners around 70-80cm long (3200-3800rpm) (remember this also includes the port in the head) and 3cm in diameter.
