1.25 v 1.5 carbs

[paulhumphries]

I have just bought a servo kit and therefore need an inlet manifold with a vac take off.
I know I can simply drill and tap one of my spares to provide such but also have a Minispares water heated item complete with 1.5 carb.
Problem is I'm 100% happy with the 1.25 and don't want to loose any economy.
If I fit the 1.5 carb is it going to affect fuel consumption - I drive for economy and nor performance even with the 1.25. ?
In fact with my driving style I cann't think of any time I found the standard 1098 lacking in power

Thanks.

Paul Humphries

[dunketh]

In fact with my driving style I cann't think of any time I found the standard 1098 lacking in power

You've really answered your own question there.

I found the 1.25 to be adequate even for a 1275 lump although changing to a 1.5 has made a noticeable difference.

[bmcecosse]

Put the 1.25 carb on the Minspares manifold ! Problem solved - performance and economy increased.

[picky]

you can keep the original carb I think if you swap your carb spacer for one of these http://www.minispares.com/Product.aspx?pid=34394

That would make the job easier.

[paulhumphries]

Put the 1.25 carb on the Minspares manifold ! Problem solved - performance and economy increased.

Unfortunatly the mounting pattern is different as I'd already thought of that
The 1098 is ultimatley going to be changed for a 1275 A + unit with autobox so I might just see if I can fit a spare diesel belt powered vac pump on in the mean time.
In fact I want to convert to alternator so I could always use, again, a spare Ford Scorpio diesel unit that has the vac pump on the back - just need to check clearance first.

Paul Humphries.

[paulhumphries]

you can keep the original carb I think if you swap your carb spacer for one of these http://www.minispares.com/Product.aspx?pid=34394

That would make the job easier.

I've got a couple of those lying around somewhere in different sizes.
They are meant for a vac guage and aren't sufficent size to allow the vac needed for a servo.
Good idea though.

Paul Humphries.

[picky]

ah i see. apologies.

[bmcecosse]

Just drill and tap two holes! Or - make a simple spacer with the correct fixings for the older carb. Lot easier than messing about with vacuum pump!!

[Packedup]

If you can find one, stick a HIF38 on and be done with. It's unlikely you'll take a notable eceonomy drop, you will get a bit more power, and it'll bolt straight to your inlet.

[alex_holden]

I suspect if the 1.5" carb is tuned correctly (ie. it has the right needle) then you should only see an increase in fuel consumption if you make use of the extra power available at full throttle. So it depends on your driving style.

[bmcecosse]

Exactly - they were fitted to the Mini to IMPROVE the fuel consumption - the HIF38 being a more modern design of carb with much better control of the fuel level in the chamber.

[paulhumphries]

Exactly - they were fitted to the Mini to IMPROVE the fuel consumption - the HIF38 being a more modern design of carb with much better control of the fuel level in the chamber.

The carb I've already got attached to the Minispares manifold is (I think) a HS4 Wax Stat.
The manifold has 4 mounting holes and the card has 2 diagonal.
It came off a 998cc Mini that the owner had changed for a complete 1275 lump.

How good / bad is the carb I've got ?
Worth trying or no use (bearing in mind I want economy over performance) ?
I'd expect to have to overhaul and change needle.

Paul Humphries

[Packedup]

The carb I've already got attached to the Minispares manifold is (I think) a HS4 Wax Stat.

*shudder*

How good / bad is the carb I've got ?

It's terrible.

However, for 2 pence it can be made good.

The wax capsule is not a good thing IMO - Maybe it's fine when new, but after a few years/ many heat cycles it starts to give up, causing all manner of hot running problems. You can pay a small fortune for a conversion jet, or alternately you pop the capsule out and stick 2 1p coins in its place

I'd prefer the HIF over the HS, but the HS4 should be fine. The Minis that claimed to get 50+mpg used them, and I got near that on a warmed over 1098 Mini on a run quite often. The engine will be less restricted, so if anything the economy will be a little better as you'll have to welly it less to make teh same progress!

[bmcecosse]

It will be fine - use it - do the 2p conversion if you like - don't bother with 'overhaul' - just clean it!!

[bmcecosse]

£42 for the Oselli manifold !! I hope no-one on here got involved in that madness! MG Metro manifold is the one to get - it works very well and used to go for £5 or so.

[Packedup]

I thought about going to 16 - 17 quid tops, inc p&p - I refuse to pay much more than 50% of the new price for s/h stuff, especially on the "bargain market" of Feebay. The moment I'd posted on here about having half an eye on it I took another look, and it was already well past my limit.

Maybe the buyer is the one who was after that silly money 1098...

I can probably get s/h aftermarket alloy inlets for around 10 - 15 from the Mini specialist round the corner, might be a business opportunity in the making...

[chrisd87]

I got a fairly good deal for my Oselli manifold then - I paid £20 for one about 6 months ago.

[dunketh]

Ebay is a total let down these days.

Complete waste of time imho. Theres always someone with more money than sense to come along and bid up 'that HIF' or 'that inlet' you were watching to comedy levels.

[picky]

ebay is very strange, i ported two 12g940 cylinder heads. sold first one for £330. sold the next one, using exactly the same description and pictures etc and it only went for £82!!!! weird.

[RogerRust]

Its the law of supply and demand.