Mumford linkage.

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mgbloke
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Post by mgbloke » Fri Nov 24, 2017 7:57 am

I have had so many issues with the conversion to Fuel injection/throttle bodies that I haven't had chance to experiment with the rear suspension settings.
From the limited time on track it just works so well.
Maybe I have been lucky and stumbled on a really good setup or possibly there might be more to come.
I learned a lot from my experimenting with the old panhard rod setup particularly with roll centre heights and the effects.
My Mumford setup has three settings to adjust the roll centre height and at present is set in the middle. If I set the roll centre height to the lowest setting I'm thinking it will improve things even more.
Next season i will try and rig up a gopro and take some footage of the linkage working while on track.



chodjinn
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Post by chodjinn » Fri Nov 24, 2017 10:07 pm

What issues are you having with efi? What ecu are you running?
RIP MGB V8 .... served me well as a learning curve.

R32 Skyline V8 .... this one is gonna be a monster!

DaveEFI
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Post by DaveEFI » Sat Nov 25, 2017 9:52 am

I've often wondered if there are any advantages using throttle bodies on an RV8 over a plenum? Giving how much more difficult they are to tune.
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scudderfish
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Post by scudderfish » Sat Nov 25, 2017 10:45 am

ITB are very sexy, but I don't know of anyone who has yet got them working well without sufficient swearing to make the Navy blush.

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Ian Anderson
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Post by Ian Anderson » Sat Nov 25, 2017 10:50 am

I'd love to have ITB on my car but the thought of all the tweaking and fiddling put me off.

Now 4 IDA or IDF carbs that is a different story, they add another element of spit back and fire! More fun

Ian
Owner of an "On the Road" GT40 Replica by DAX powered by 3.9Hotwre Efi, worked over by DJ Motors. EFi Working but still does some kangaroo at low revs (Damn the speed limits) In to paint shop 18/03/08.

chodjinn
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Post by chodjinn » Sun Nov 26, 2017 9:53 am

I did have ITBs for my 1UZ but sold them when i went turbo. There was no point in having them.

They are probably a slight advantage on a high power n/a if setup correctly. Usually best to get a tuner who has experience and knows what they are doing.

Was at a place in chesterfield yesterday fixing my TT amd the bloke in the unit next door tunes TVRs. Had a chimera in there with the act triple plenum on emerald, sounded awesome once he got the timing right.
RIP MGB V8 .... served me well as a learning curve.

R32 Skyline V8 .... this one is gonna be a monster!

DaveEFI
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Post by DaveEFI » Sun Nov 26, 2017 11:18 am

I'm sure you can get slightly more peak power out of them. But what about the rest of the power/torque curve if it's a road car?
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mgbloke
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Post by mgbloke » Sun Nov 26, 2017 12:12 pm

well, I started with some used 45mm jenvey throttle bodies purchased from John Eales with manifolds, thermostat housing and sagem coilpacks.
Decided to get a local firm to fit all the hardware with fuel tank mods using a Canems ECU supplied and fitted by them costing £3600
iIt never ran properly with spurious missfiring problems. every time i took it back they would change something and give me a bill for a few hundred pounds each time. they also said that my 60amp race alternator was too small effecting fuelling so i fitted a 120 amp one which made no difference.
After 18 months of so of dissapointment i had big end failure so decided to have a fresh start with a new V8D 5.0 short engine with TA heads.
Still it wouldnt run without intermittent missfiring and now a new problem was serious smoking out the exhaust but only on track, was fine on the road !.
By this time I was so fed up and after replacing nearly everythin I decided that I needed a new ECU.
Following a Recomendation from my brother I used a company in wales who fitted a LINK G4+ extreme ecu.(3200) The ECU is great but the company was worse than useless keeping the car for 4 months and handing it back in a terrible state. Anyway I collected the car and booked a trackday. What a disaster the car missfired so badly that I could only do one lap and on top of that It still smoked.
After messing around with valve stem seals I decided that it was the rings, did a leak down test which revealed that NoS 4 and 5 were bad.
At this point I decided to have the short engine overhauled by ACR who i must say were very good.
I decided to investigate the wiring and found that the original installation used an old block connector presumably from a range rover to feed the coilpacks one wire to this connector had a cable break making 2 cylinders fail intermittently. I sorted this out and tidied the awful wiring job.
ACR recommended A guy in east London to do the mapping after a day on the rollers I was dismayed to find when i drove it next that it would go very lean when accelerating hard. took it all the way back and after another 3 hours on the RR it was better ( I am pretty sure he was not familiar with this ECU).
Booked a trackday and guess what? It was smoking like hell. ( this was a new engine with new pistons and rings ).
This time I suspected the heads and after i pressure tested the inlet manifold runners i found that numbers 4 and 5 were leaking.
After investigation i found that The inlet pushrod holes has been machined closer to the runner making the metal so thin that a small hole had appeared (not easy to see).
Had these two pushrod holes sleeved and at the next trackday the smoking was gone.
Now a new problem It would accelerate for 3 or 4 seconds but then would go lean an felt like was fuel starvation.
Changed both fuel pumps (red top lift pump to swirl pot and 044 bosh FI pump).
Extended the fuel regulator guage so that is is visible from the cabin and tested it on the road.
This time it accelerated cleanly and seemed to be faultless.
All the above has taken place over the last 4 years and this is where i am at now.
I have a trackday booked for 9th Dec at Castle combe just to test that all is working properly and get some logging then it is Off to Norris Designs on 13th Dec to check fuelling as they are LINK dealers.
It has cost an absolute fortune!!!
Hopefully it is sorted.
Mark

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Post by DaveEFI » Sun Nov 26, 2017 3:05 pm

Oh dear. Quite a tale of woe. I'm not surprised you had wiring problems - very few indeed seem to take the trouble to make or modify a loom properly. And many years as a sound engineer told be that any wiring problem is most likely to be at a connector.

Not convinced there's that much difference between all the various aftermarket ECUs in performance, if to the same basic spec. More a question of getting it installed/set up correctly. And that can be difficult.
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mgbloke
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Re: Mumford linkage.

Post by mgbloke » Wed Oct 31, 2018 5:11 pm

Finally I got the engine running right. problem was faulty wiring (Crank sensor).

Back to suspension.
I have a track day booked at Silverstone on 21st Nov.
Trying to mount a gopro under the car to see how things are working on track but very difficult to do as fuel tank is directly behind axle.

I am so please how the car is transformed, the rear seems to dig in and grip when cornering hard hopefully will see exactly what is happening.


cheers.

mgbloke
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Re: Mumford linkage.

Post by mgbloke » Sat Dec 01, 2018 7:54 pm

well, the Silverstone trackday was damp and slippery. Couldn't mount the camera underneath. Here is a clip from the day chasing round after a Porsche GT3 and a couple of high HP 600+ evos. Very pleased with the handling and balance although a few tweaks to perfect.

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