Weber setup?

[villa.1]

Has anyone made a cold air box for 3x Webers? if so i would love to get some more info on design etc. I'm about to fork out on 3x K&N's but whilst they look very prety I was a bit concerned about the hot air from the pheonix manifold on the rear carbs.

[Guest ntc]

I have the master's PI, but PI or Webers, you gotta be a masochist either way...

 

If I were starting again I'd have a blower.

 

Ivor

 

I have the master's PI, but PI or Webers, you gotta be a masochist either way...

Nice one Ivor

we will have to meet up for a pint one day

Regards

Neil

[88V8]

Has anyone made a cold air box for 3x Webers? if so i would love to get some more info on design etc. I'm about to fork out on 3x K&N's but whilst they look very prety I was a bit concerned about the hot air from the pheonix manifold on the rear carbs.

 

I think Revington do one?

 

Yes, here it is.

http://www.revingtontr.com/shop/mainframe....oductID=RTR4423

Edited August 14, 2008 by 88V8

[Guest ntc]

Has anyone made a cold air box for 3x Webers? if so i would love to get some more info on design etc. I'm about to fork out on 3x K&N's but whilst they look very prety I was a bit concerned about the hot air from the pheonix manifold on the rear carbs.

 

I am currently having a air box manufactured with a provision for a PCV valve incorporated it will be available in alloy or stainless but this is at r&d status

 

Neil

Edited August 14, 2008 by ntc

[TR6 Poor]

I am currently having a air box manufactured with a provision for a PCV valve incorporated it will be available in alloy or stainless but this is at r&d status

 

Neil

Can you say the name of your company?

[stephen cooper]

Yes, one of the first things we soup-uppers tend to do is take off the manufacturer's lumbering great air intake/filter that draws nice cold air from somewhere, and put in little dinky filters that go swoosh and kid ourselves we've made an improvement, whereas what we've actually done is detune the engine because colder air is denser and entrains more fuel and gives more power - after all how do you get more oomph from a diesel (diesel - yuk ) you bung on an intercooler to cool the charge, or a bigger intercooler to cool it more, and indeed even when we do know about this cold-air thing as I do sometimes we still persist in our silly little filter, like I have on the V8 in my Landy, drawing air from the worst place over the exhaust manifold(s) just like the TR in fact, so do I put the maker's pile of tinware back on that drew fresh air from the cooler centre of the V that would be much better, of course I don't but what I have done is cut two 4" holes in the top of the bonnet and put in two cabin vents from a boat, well one can do that sort of thing with an old Landy, and boy! what a difference in the performance, it really hated getting hot the power just fell away and now it doesn't, doesn't get hot I mean, although quite what the vents are doing I don't know, if I had a smoke gun I could find out but I suspect that at idle they let hot air out and as we go faster and the engine sucks harder they let cool air in but perhaps because there's more air coming in through the rad when we go faster - faster is a relative term in my Landy - perhaps they actually let hot air out all the time, anyway it really makes a difference.

With your car, if you've tuned and balanced it with the bonnet up so the carbs get unlimited cold air, I guess the only way you'd see how much your ingenious fan has mitigated the effect of shutting them up with all that hot air is with a sensor in each exhaust pair on a resistance rolling road not one of those useless, well pretty useless, inertia things.

Or of course you might see it in the plug colour as the centre carb will in effect run weaker and the back one weaker still, which unfortunately mirrors the heat pattern due to proximity to the rad and the air intake anyway, so that probably makes it hard to get any clear message from the plugs.

When you get it on a roller, you might like to try the HP with the bonnet open, and then close it and get everything heat-soaked and with no other changes try it again. That would be interesting.

I bet on a lot of carbed engines there's well over 10% extra HP to be had from feeding cold air as opposed to hot.

Now where did I put that pile of tinware???

 

Ivor

 

 

Have you tested all of that? Ever thought there might be some airflow going on under the bonnet at speed? There's an awful lot of cars running around with aftermarket air filters/free flow filters instead of the original item. Yes cold/still air is beneficial but I wouldn't be so quick to quash free flow filters when in the case of the TR6 you have the canister and plenum which is a tin box getting above an exhaust manifold!

[Alec Pringle]

"There's an awful lot of cars running around with aftermarket air filters/free flow filters instead of the original item."

 

Damn right, and full marks to the marketing boys

 

To be sure there's a lot of airflow under the bonnet at speed - a good proportion of which has travelled through the radiator, picking up heat along the way. Most of the airflow exits under the car, which doesn't necessarily leave a huge amount for the underbonnet air filters to ingest.

 

Competition cars can be a different story, with additional air exits underbonnet to divert that which might more usually flow under the car, and providing more airflow to engine breathing.

 

Nevertheless, track testing (as opposed to rolling road testing) surprisingly often highlights a benefit from a cold air intake trunked to the inlets, despite the potential weight penalty, even on a competition car with revised underbonnet airflow.

 

But there are no hard'n'fast rules here, it's one of those grey areas where black art and science mingle !

 

Cheers,

 

Alec

[88V8]

Have you tested all of that? Ever thought there might be some airflow going on under the bonnet at speed? There's an awful lot of cars running around with aftermarket air filters/free flow filters instead of the original item. Yes cold/still air is beneficial but I wouldn't be so quick to quash free flow filters when in the case of the TR6 you have the canister and plenum which is a tin box getting above an exhaust manifold!

 

Yes there are a lot. Some manufacturers used to fit them to their sporty models, not because it was better but because that's what the buyers expected to see under the bonnet. As Alec says, a TRiumph of marketing.

 

Have I tested it? Well, I know for a fact that the air vents in the bonnet made a huge improvement to my Landy, both idling and at 'speed'

 

Moreover, the TR6 tin box is constantly cooled by fresh air from in front of the rad. It takes no air from the engine bay.

 

It's even better when the tin box is chromed, as it then reflects more heat... as if one needed an excuse..

 

[TR6 Poor]

Anyhow, no need to stop this thread now. I would like to see some rolling road results for the Webers, seems MI5 has them all under lock and key. Anyhow, I can get a 50 pound discount if I don't want the Lucas fuel pump with the rest of the PI set up. Is there any reason I would need the Lucas pump? I was planning on using the Bosch set up. What's the chance of the original CP metering unit still working without overhaul? Thanks

[stuart]

Anyhow, no need to stop this thread now. I would like to see some rolling road results for the Webers, seems MI5 has them all under lock and key. Anyhow, I can get a 50 pound discount if I don't want the Lucas fuel pump with the rest of the PI set up. Is there any reason I would need the Lucas pump? I was planning on using the Bosch set up. What's the chance of the original CP metering unit still working without overhaul? Thanks

Depending on how long the unit has been sat around (original seals not compatible with unleaded) slim to none!

Stuart.

[foster461]

Depending on how long the unit has been sat around (original seals not compatible with unleaded) slim to none!

Stuart.

 

 

And no reason to lust after a Lucas fuel pump. Just make sure that the chosen pump and the relief valve match.

 

Stan

[88V8]

At Cranleigh on Sunday, remembered this thread, here are a couple of arrangements where the designers have been careful not to draw the intake air from above the exhaust.

The first is an old Wolseley, the second a MkI Lotus Cortina. Both, I am sure, are original.

 

It does seem to me slightly perverse to go to the considerable trouble and expense of a Weber or other multi-carb installation and then draw thin air from arguably the worst place on the car...

 

 

[Alec Pringle]

Come on Ivor,

 

we've had 10 pages of re-inventing the wheel on Weber bl**dy carbs.

 

For heaven's sake, they're race carbs not road carbs, they're not an adequate substitute for PI, and if you have to have a trio of twin-chokes then use Dellortos that do the job better.

 

Preferably with the assistance of a good rolling road and a good operator.

 

Meanwhile, there are more interesting topics like sex, and beer, and rock'n'roll, and real TRs !

 

Cheers,

 

Alec

[foster461]

Come on Ivor,

 

we've had 10 pages of re-inventing the wheel on Weber bl**dy carbs.

 

For heaven's sake, they're race carbs not road carbs, they're not an adequate substitute for PI, and if you have to have a trio of twin-chokes then use Dellortos that do the job better.

 

Preferably with the assistance of a good rolling road and a good operator.

 

Meanwhile, there are more interesting topics like sex, and beer, and rock'n'roll, and real TRs !

 

Cheers,

 

Alec

 

 

Alec, I think Ivor's point is that no matter what form of induction you have, a cold air supply delivered to the carbs from the front is better than sucking in warm air over a hot exhaust via two or three shiny filters, and that would apply to the Webers, Dellortos, SU's or the standard twin Strombergs.

 

I think we are mostly in agreement that 3xdcoe's are overkill for the majority of street engines, tuned or otherwise, and I hope that most that go down the Weber route understand that before diving in. For the PI engines, the answer is simple, stick with the PI. For the USA engines, the lobotomised, cant get out of its own way, 100HP at the flywheel engines, once the compression ratio has been raised and a proper cam fitted etc you have to get more gas into the head. Your choices for off the shelf solutions are triple strombergs, supercharging, Webers or Weber clones or Weber equivalents. These are all projects in their own right and for a real adventures you can also go down the TBI, EFI or even PI route. Given everything else that you have to do to get to that point I would argue that chosing between one or the other is a **** shoot regarding ease of installation and configuration and each has its merits and idiosyncracies. In the end you pays your money and takes your choice and I suspect that the best of each configuration probably performs about the same with perhaps differences in throttle response and torque curves.

 

 

My Weber setup was pretty inexpensive, around $1700 for three carbs, manifold and linkage (all new) with another $100 for adapting/integrating with the rest of the TR6 engine. There is a community of support for the Webers on the TR6. My carbs have best guess jetting in them for now and the car still goes like stink, comparable if not better than my original 1972 PI TR6 (R.I.P) and about the same as a supercharged unit.

 

Webers may be overkill but they are available, affordable and viable for this application and they look the bees knees.

 

Stan

[Nick Rowe]

Nick,

 

There are loads of good places.

 

Where are you?

 

Regards

 

David

 

Hi All,

Just to close my particular chapter of this novel, I have had my TR6 (the one with triple Webers) tuned on a rolling road by Sigma Engineering, Gillingham, Dorset. It was both an interesting and a frightening experience. The first thing checked was the timing and then because the timing strobe was not working above 3500rpm, the plugs, leads, caps and coil were all checked. Finally the distributor was stripped down and the advance/retard increased from 7 to 10 degrees.

Mr Lander suggested Webers were not ideal for a road going TR although when he further investigated he approved of the setup and said it was 'OK'. Some experimentation took place with the fuel and air jets and the car was put through its paces. I have never taken it into the red before although I was assured my tacho was reading 500-1000RPM too fast.

Anyway the result was 120BHP at the rear wheels, removal of the flat spots, better pick up and no more spitting back which apparantly is a known issue with Webers.

Going by the fuel consumption on the way home I think it now unlikely I will achieve the 30ish MPG I got on the Classic Le Mans trip, more like the advertised 20MPG, but the improvement in acceleration, smoothness of pick up and all round general better feel makes it worthwhile.

Should have had it done years ago !!

Cheers

Nick

[foster461]

Hi All,

Just to close my particular chapter of this novel, I have had my TR6 (the one with triple Webers) tuned on a rolling road by Sigma Engineering, Gillingham, Dorset. It was both an interesting and a frightening experience. The first thing checked was the timing and then because the timing strobe was not working above 3500rpm, the plugs, leads, caps and coil were all checked. Finally the distributor was stripped down and the advance/retard increased from 7 to 10 degrees.

Mr Lander suggested Webers were not ideal for a road going TR although when he further investigated he approved of the setup and said it was 'OK'. Some experimentation took place with the fuel and air jets and the car was put through its paces. I have never taken it into the red before although I was assured my tacho was reading 500-1000RPM too fast.

Anyway the result was 120BHP at the rear wheels, removal of the flat spots, better pick up and no more spitting back which apparantly is a known issue with Webers.

Going by the fuel consumption on the way home I think it now unlikely I will achieve the 30ish MPG I got on the Classic Le Mans trip, more like the advertised 20MPG, but the improvement in acceleration, smoothness of pick up and all round general better feel makes it worthwhile.

Should have had it done years ago !!

Cheers

Nick

 

Nick, that sounds like a good outcome and you are fortunate that you have access to someone with the expertise and facilities and the stock of Weber components that can dial in your carbs. I doubt that there is anyone within 1000 miles of me that is able to do that. If your system is now set up you are in good shape as there is nothing that should make them suddenly start to drift off, so just enjoy. 120HP at the wheels sounds pretty respectable, comparable with the early PI cars I imagine, reflecting around 140 to 150hp at the flywheel.

 

I'm getting 26mpg (US galls) with mixed city/highway driving which is not a long way off from what I was getting with the twin Strombergs.

 

Stan

[foster461]

I got my car on a Dyno yesterday and made some minor changes to the air correctors to lean the mixture out a little. This is an interim measurement as I still have other mods planned but so far I think I am on track for my goal of an engine that would match the original PI cars.

 

Dyno chart here, comments welcome.

 

http://i38.photobucket.com/albums/e119/fos.../Foster-TR6.jpg

 

Stan

[Guest ntc]

Hi Stan

The results look ok the drop in torque seems excessive though I would think this is probably down to poor exhaust extraction ? or cam but all in all if your happy with the way the car drives that is all that matters

Ps Good to see the thread is still alive

Edited September 25, 2008 by ntc

[TR6 Poor]

Thanks for the dyno posting. I don't think you can get much more with that cam, just my opinion. As it idles well, there can't be alot of overlap. Do you know what total advance your are running?

[foster461]

Thanks for the dyno posting. I don't think you can get much more with that cam, just my opinion. As it idles well, there can't be alot of overlap. Do you know what total advance your are running?

 

I think I have another 10-15 HP locked up with further carb refining, better ignition and better exhaust but I'm not sure that the cost (probably another $2k) would be worth it.

 

I'm running a rebuilt and modified 22D6. My static timing is 10 degrees BTDC, no vaccum advance or retard, total of 19 degrees mechanical advance on the dizzy that was recurved by Bob Sarama. So I guess I have a total of 29 degress of advance possible. He provided a stop that I can put onto the post to reduce that mechanical advance by 2 degrees if I need to but I have had no reason to do that.

 

Here's what the dizzy looks like:

 

http://i38.photobucket.com/albums/e119/fos.../dizzycurve.jpg

 

 

I would like to understand why the initial AF numbers are so lean. The procedure on the dyno was to get into 4th gear and bring the engine up to 2k rpm. Then to floor the accelerator and signal the tech to start the telemetry. So by the time we are at 2500 I have just mashed the pedal 2 seconds ago and there should have been a good squirt of gas from the each of the 6 accelerator pumps so I was actually expecting to see it rich at 2500 rpm not lean.

 

Stan

 

[edited to add link to dizzy info]

Edited September 25, 2008 by foster461

[foster461]

Hi Stan

The results look ok the drop in torque seems excessive though I would think this is probably down to poor exhaust extraction ? or cam but all in all if your happy with the way the car drives that is all that matters

Ps Good to see the thread is still alive

 

The torque does drop off after 4k rpm and I'm sure the stock header and two pipe system with stock muffler is not helping it but it does drive very nicely, pulls on a hill from 2k rpm in 4th with no reluctance and I can floor the accelerator at 80mph in 4th OD and feel the car surge forward as if it has plenty of energy left. Good job really as the ambient speed on the highways around Boston is probably 80mph.

 

Stan

[88V8]

I would like to understand why the initial AF numbers are so lean. The procedure on the dyno was to get into 4th gear and bring the engine up to 2k rpm. Then to floor the accelerator and signal the tech to start the telemetry. So by the time we are at 2500 I have just mashed the pedal 2 seconds ago and there should have been a good squirt of gas from the each of the 6 accelerator pumps so I was actually expecting to see it rich at 2500 rpm not lean.

I believe the accelerator pump only smooths the transition from one airflow state to another. When one opens the throttles suddenly, the venturi cross-section increases, the vacuum collapses, venturi airspeed falls off, and with it the fuel suction across the jets.

Without temporary enrichment, the engine would bog. One experiences this if trying to accelerate after the choke is pushed in too early on a cold engine.

 

Around 2,000 rpm the engine is doing c30 revs/sec, so by 2,500 rpm that slug of fuel is just a twinkle in the eye of time.....

 

Ivor