6 replies to this topic

[Mrpeanut]

This is probably a silly question but what difference does a different damper make? I've swapped carbs (new hif44 for old). The old had a 2085 (I think)damper and the new a 1055 (I think). I stayed with the old one but what's the difference, and the point of a different damper?

[ACDodd]

The differences are in the fit, giving changes in the up and down motion. The 2085 damper is the one to use on a performance SU. It will eliminate flat spots between gearchanges.

AC

[mingy]

I am using an HIF44 on my 1380, is the number 2085 actually on the black cap, and what oil would you use in the damper well.

[Mrpeanut]

Cheers AC. The 1055 (or whatever) came from a carb fitted to a 1380 track car. Does that mean he had the wrong damper and I'm better off with the other one? I'm only running a standard 1275 with stage 3 head.

[Mrpeanut]

Mingy, yours is the opposite of the set up I bought! The dashpot oil is a good one. When we fitted the carb one fella (ex mini racer) swore blind that 3 in 1 was best; another (mechanic and mini nut)said 10/40 and I wanted to use 5/30 synthetic but was told off.

What's the definitive answer to that, and why?

[ACDodd]

Unfortunately damper wear. They are also originally made to tolerances, as a result some come up loose some tight. Also the dampers can be modified, so there is no guarantee what you got is right or even original. The only thing I can say that is an LZX2085 is the best starting point. LZX1505's are usually too slow to return, LZX1511 are usually to quick to open and too slow to return. LZX1773 is the worst of all. All can usually be modded to make them what you actually need.

As a result of the tolerance and wear issue, there is no correct oil for YOUR su. The oil needed for you carb is the oil that gives the correct fuel enrichment on acceleration. At MLMotorsport when I carry out my optimised tuning sessions, I have 4 different oil grades to enable me to dial in carbs to suit the application. I also have files and a bench grinder all for piston damper tuning, and matching on twin setups.



AC

[Mrpeanut]

Blimey, these minis!

AC, please PM details of when you tune in Salisbury (sat please) and an idea of charges and I'll get in touch to arrange an exchange of pound notes for a sweet running mini.