Rover V8 Boxer carb installation blog

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Riley RMF
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Rover V8 Boxer carb installation blog

Post by Riley RMF »

Ok - there's a fair amount of odds and ends relating to the Boxer carb setup on this forum, but having trawled the Internet at length I can't find a self-consistent set of information about how to get them installed and set up.

I've fallen at the first fence though and can't work out how to get photos off of my computer and into these postings! If anybody can give me the necessary sequence of events to do that I'll put up some pics of my project and update progress as it goes along.

Yeah - I know there are a whole range of options on carbs I could use, but I want to try the Boxer setup purely because I want to.

Once I can post pics I'll put up some more info on my project.

Thanks

Phill



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Post by ChrisJC »

You have to host your pics elsewhere and link to them from here.

It will be interesting to see how you get on as the dual-plane firing sequence really does not lend itself to the boxer carb arrangement!

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Post by Riley RMF »

Thanks Chris - I'll try that then.

Yeah - I've read a fair bit about that and understand the problem. Always one for a challenge!

Cheers

Phill

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Post by DaveEFI »

You'll certainly have fun and games tuning one of the carbs. Not sure you'll ever get it perfectly clean over the entire rev range. I've wondered if a pair of 2" would do a better job?
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Post by Riley RMF »

Yeah Dave, I know.

But I'm going to do it anyway because it's the sort of thing I like doing!

Phill

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Post by Riley RMF »

The best information I've found on the Boxer manifold so far is here:
kiwicar wrote:Hi
I had a set of these a few years ago on my range rover, and I have posted up some of my experiences with them on here before. I was in tough with the chap who designed the system when I installed mine and found the following.
1/ the carb withtwo cylinders firing one after the other (90 degrees apart) on mine needed a the spring in the piston to be slightly stiffer, this I achieved by cutting a couple of coils off and stretching it
2/ same piston required thicker oil in the dashpot (I used hypoid 90 I think)
3/ again on this carb I ran it "leaner" by putting the needle in the piston on the lower indent (to get over the richening effect of the heavy "pulsing" on this carb.
4/ springs in all 4 SUs were lighter than standard, but I don't remember which ones I used
5/ the needles rcommended had a richer top to them, but I think 3/4 of the reason for this was the K&N filter kit I had.
6/I rounded the leading edge of the piston on each carb, this again richens the top end of the rev range.

To be honest I found the whole set up very difficult to keep running in a good state of tune, if I had new carbs and unworn linkages that would have been better (I modified my carbs eventually to eliminate 1 set of linkages which improved things). The set up was very good off road in that it was pretty well imune to being at odd angles, and pickup was good but I felt it would have been better with more development. Maybe bigger ballance pipes between pairs of carbs??
Best regrads
Mike
Which gives a pretty good account of the major issues, and is my starting point for the practical experience.

On a forum like this it's only possible to work in bite size chunks - I could write you an essay on what I've been doing so far, but one step at a time.

So, I've done a fair amount of analysis from a theoretical standpoint and come to the conclusion there is no needle you can go and buy that's going to work properly.

I bought a Boxer/HIF44 setup on Ebay for about £100 in about 7 years ago, and have finally got around to playing with them. They had had a lot of use (so somebody made them work!), and came fitted with BAU needles. From the analysis I've done so far these would exhibit the exact behaviour that Mike describes above.

Ignoring for the time being the problem of cylinders 5 and 7 firing 90 degrees apart, to get the needles needed it seems to me there is only one solution, you have to make them yourself. Happy to be told I'm wrong on this, it would save me a lot of work!

So let's start at the very beginning. Is there a copy of the original installation instructions anywhere still in existence? That has to be the right place to start...

Phill

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Post by Eliot »

Here's a full write up I received from the creator of the Boxer manifold - Martin Goodwin which can be found on my Rover V8 Manifold archive page:
http://www.mez.co.uk/ms12-new.html


"The Boxer Quad SU system was developed in 1993, primarily for the for the off-road market, after Dave marsh ( M.D. of QT Services, WILDCAT ETC.) saw a standard Rover SU manifold that had the top cut off, and in it's place, two carb-mounting turrets were welded on to accept an extra pair of carbs.

It was noted that the pick-up of the engine was massively improved over standard but it was not an easy conversion to do. Also, it relied on finding a sacrificial manifold in each case, to cut and shut.

Myself and my brothers' background was in engineering and my father, who knew Dave well, had much experience of building and setting up all types of engines. We agreed to make a proto-type steel-fabricated pair of crossover manifolds and Dave's racing sponsor at the time would give us the facility to rolling road test them.

Through much research we came up with the design of manifold that you see today, ( more or less,) and when tested on Dave's Comp' Safari racer, it was useless. The reason being, that the SU's, being constant-depression carbs, were unable to settle properly in the configuration. After retro-fitting a balance pipe system, the set-up finally came good and we realised the full potential. There were leaps in performance in both power and torque with no trade-offs of any sort really.

I continued to develop the system over the next four years, testing on Dave's Vehicle, with which he had much success in competitive events. The final manifolds were even better than before with a revised runner shape and internal balance passages. I must acknowledge the expertise of Dave Arnold, who did most of the rolling road work and was Dave Marsh's co-driver. He knows his onions and helped us to make the RV8 the success that it was.

Right from the start, the vacuum balance was key, and when Burlen Fuels Systems (licence holder for manufacture of SU's.) tried to copy our work, they didn't understand fully what they were doing and ran a test against all the other induction systems of the time, with appalling results. This was published in Fast Car Magazine and we were dragged down with them as everyone assumed our stuff was the same. I asked at the beginning, to be included in this shoot-out but Fast Car declined. I was never given a reason, I just think the big-boys were scared of what we could do and they spent a lot of money advertising in Fast Car. I think you can work it out.

If you can un-earth an earlier copy of Fast Car from April'94, you can see what can really be achieved. Back-to-back against the standard manifold and carbs, on the same mildly tuned 3.5 engine, on the same day and overseen by journalist David Hardcastle, we gained 42bhp at 5000 rpm and 34 bhp at 6000 rpm, at the rear wheels, not to mention power gains at all lower engine speeds as well. We could even beat the fuel economy over standard.

With a gradual drop in sales and the increasing use of fuel-injection, plus a quality product that didn't wear out, I couldn't make money and wound Boxer Engineering up in '98, I think.

Don't underestimate the humble SU though. Massive torque, more than any other carb, due to fast air-speed over the jet at all times. Even when you have twice as many with the corresponding power increases, the engine remains tractable low down. Concentric float-chamber, they'll keep going,even upside down."



Some tips though:
Radius the front edge of the slides but not too far up or the key comes out of the key-way slot and they stick fully up.

Fit parallel trumpets instead of the Rover inlet castings to prevent a standing wave in the mouth of the carb.

Use a nice heavy oil in the damper pots. This is your temporary enrichment on acceleration and it transforms your pick-up to a Weber-type 'kick in the pants' .

The later HIF44 models had damping both up and down on the slides making them much more stable in the pulses of a quad-carb system.

Take the trouble to measure the CO at the exhaust-manifolds individually or you can't get the best out of them. All you need is a threaded hole or boss that you can plug when not in use, one per carb. Make a short pipe that will screw into this point to measure the gases, or even better, make several. As mentioned before, you get a higher reading at the headers than the tailpipe. Set 5&7 rich to help them out
[/i]
Eliot Mansfield
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www.mez.co.uk / www.efilive.co.uk

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Post by Riley RMF »

That's brilliant Eliot thanks - I'm really pleased to find it can be done!

Phill

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Post by Eliot »

I wouldn't bother personally - all seems like too much hassle. I assume you particularly want carbs over a bolt-on efi setup?
Eliot Mansfield
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Post by Riley RMF »

Yup - it's a 1950's car and the SU carbs just look right under the bonnet...

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Post by stevieturbo »

Use the carbs as throttle blades and hide the injector mounts/rails somewhere underneath ! lol
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Post by Eliot »

stevieturbo wrote:Use the carbs as throttle blades and hide the injector mounts/rails somewhere underneath ! lol
Indeed - I'm sure it's been done with SU's before - i remember reading about it on the megasquirt forums years ago.
Eliot Mansfield
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Post by Riley RMF »

Yeah - thanks guys, but for the time being I'll take this Boxer thing through to its logical conclusion.

So this is adventures in posting pictures. I've put these up on facebook, I don't know if that means you have to be a facebook member to see them - let me know if you can't see them and I'll try something else.

So here are some Boxer manifolds that have appeared on Ebay. This one looks reasonably complete:

Image

Image

And this is what I bought - I kept the pics from the original listing:

Image

Image

So lets's start with a simple question. Clearly from what's gone before, the vacuum balance is an important issue. In the first pair of pics all four carbs are connected, in the second they are connected in pairs.

Anybody have any direct experience of this on this manifold? The first pair of pictures look like a more original system, and the metal pipe connector running along the top looks authentic.

Phill

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Post by Riley RMF »

Well that didn't work. No pics :(

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Post by DaveEFI »

Riley RMF wrote:Well that didn't work. No pics :(
You need a site which does third party hosting. Photobucket used to, but have withdrawn it as a free service. Will now cost you something like £300 a year.
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