supercharged 1275 home brew. anybody fancy a blown minor?

Post by **chrisd87** » Fri Feb 08, 2008 4:48 pm

To be honest I don't reckon you'd get much extra power from a ram-air system on a Minor. The main benefit would probably come from the air being colder.

Some high-performance motorcycles use it (Suzuki SRAD) but these bikes are capable of 150mph+, so it's doubtful that you'd get much of a noticeable increase from something going half that speed. It can also make the carbs freeze in very cold conditions.

Post by **Orkney** » Fri Feb 08, 2008 5:08 pm

Well wasnt a minor but was an a series, must be a point where you are reducing suction and putting pressure.
Put your hand on a carb inlet under power, theres a great deal of suction, put your hand out teh window doing 70 and theres a great deal of pressure from wind resistance.
Course with a ram air you can multiply the inlet area, so you might be talking about 40 or 50 mph and your seeing a serious benifit if your scoop/inlet is big enough.
Pretty sure whatever it must be negligable or it would have been done to death by now, fact remains cant see why it hasnt been better explored given the lengs some people goto just to get an extra couple BHP.

Post by **superchargedfool** » Fri Feb 08, 2008 5:25 pm

Pretty sure whatever it must be negligable or it would have been done to death by now, fact remains cant see why it hasnt been better explored given the lengs some people goto just to get an extra couple BHP.

you mean like supercharging???????????????

Post by **Orkney** » Fri Feb 08, 2008 6:06 pm

you mean like supercharging???????????????

no i think supercharching is more than a few (ie 3 or so) extra BHP

was refrering to the people who take engines to the extreme, full on race type builds.
So many factors can effect the performance. Vizard is a good startng point, and then there are people who will tweak on that. But of course when you go blown its no longer a normally aspirated so a different class.
Think the trouble is you can bolt on a turbo or SC and you get so much extra bang for your buck that often many refinements are overlooked.
There were a couple of chargers on fleabay not too long ago and oh wish I'd had the money to buy them.
Cant wait to see when Picky gets his build resolved because that might be a cheaper way of doing it. (well after he's re-written the book & found all the pitfalls

)

Post by **heathy12** » Fri Feb 08, 2008 9:19 pm

ANother Turbo'd minor to the fold!

Welcome aboard fella!

Is that five turbo'd minors were upto??!

Cant wait to get mine back on the road this summer hopefully! Gona be sweet!

Mines running 113BHP. Insane in such a small car! Great fun overtaking though!!

Post by **bmcecosse** » Fri Feb 08, 2008 10:01 pm

Only slight -ve I see with the manifold is preferential flow into the 1/2 port and slightly less into the 3/4 port. But in practice it will likely be fine !And yes - ram is useless! Recently someone on Minifity did trials with various ram ideas - and LOST power probably because the turbulence upset the carb.

Post by **superchargedfool** » Sat Feb 09, 2008 9:37 am

i had already thought about biasing in the manifold and do intend to weld lambda sensor bosses into 1st and 3rd sides of 3 branch. Will make setting up much easier with lambda readings to go by. had contemplated having digital lambda readout on dash but thought it might be overkill.

Post by **superchargedfool** » Sat Feb 09, 2008 2:33 pm

as you can see yesterday went well and apart from rad fan and a few little jobs, its in, its running and I am well happy.

all seems too good to be true.

no smoke, rattles or drips.

Starts lovely hot or cold.

Runs like a sewing machine and sounds really subtle on tickover.

Revs rise rapidly when it comes on boost. Gauge was showing about 5psi at full chat before engine came out for pistons, so quite sensible. I am not looking for huge power just 100bhp plus, its more about the building it than the bragging figures!

My theory is if I can get 110bhp in 800kg i will have power to weight of 138bhp/ton which should give 0 to 60 of high 7's or low 8's.

Haven't been brave enough to venture out in it yet but will do next week. I want to drop oil and check it over first after running it up a few times.

Post by **aussiemike** » Sat Feb 09, 2008 4:10 pm

THAT LOOKS EXCELLENT!! NICE WORK, keep us up to date with how it performs please. cheers, michael.

Post by **GAS** » Sat Feb 09, 2008 8:17 pm

Sweet

Post by **bmcecosse** » Sat Feb 09, 2008 8:33 pm

Looks great - top rad hose is a wee bit strained, probably best to look for one with a moulded bend in it. And stick a breather pipe on the brass inlet on the side of the carb. But - a very neat installation. Will the weight of the carb/filter on the end of that long 'arm' not cause some problems at the scharger? Maybe a support strap/ strut at the carb would help ?

Post by **superchargedfool** » Sat Feb 09, 2008 9:44 pm

hi folks.

as for the top rad hose my theory was as the rad will get moved back by 10 to 15mm to make room for the rad fan the rad hose will become happier (hopefully).

the breather on the carb is actually the petrol overflow isn't it? i will stand corrected if I am wrong. i was planning to fit an 18 inch pipe to low down as per the normal minors.

i will show in photos to follow but the carb inlet elbow is very well mounted and more than up to the weight hanging of it.

I am well happy with the carb and air filter, it almost looks right rather than added, if you know what I mean. By the way the very cheapo air filter is something that was kicking about in the workshop rather than one i picked!

I couldn't quite resist the temptation to try it out. i only used first gear and didn't leave my premises but I will say that it goes well sideways in first when letting the clutch up quickly at 2000rpm and flooring it.

I couldn't decide for a while weather to aim for the under bonnet to look in your face or subtle but I am trying for subtle, hence painting a lot of the made bits mowog green.

The ancilliary pipes will all need some tidying up but this will come (next week).

In the next few days hopefully I will drive it, love it and not blow it! Posts of progress will be forthcoming! If all goes well (including problems that have to be solved) bhp and torque figures, 0 to 60 by gps, possibly trackday experiences will all be shared within the month. I have always been optimistic by nature.

So far (remember I am only less than a month into this) it is all going too bloody well to be true!!!!!!!!!

Post by **Spag** » Sun Feb 10, 2008 8:05 am

All looks good !!!

Got a blowback valve or anything in the plenum?

Also, what sort of brace/support underneath the inletty stuff & blower ???

Post by **paulhumphries** » Sun Feb 10, 2008 9:54 am

bmcecosse wrote:Looks great - top rad hose is a wee bit strained, probably best to look for one with a moulded bend in it.

I'm sure someone posted a while ago that the MGB thermostat cover fits and the pipe stub is at a better angle for 1275 installations.

Paul Humphries

Post by **superchargedfool** » Sun Feb 10, 2008 10:58 am

morning all.

The top rad hose i think will be happy enough when the rad goes back a bit to make room for the fan.

Got a blowback valve or anything in the plenum?

Also, what sort of brace/support underneath the inletty stuff & blower ???

no blowback valve as yet, I hadn't thought off that. At the moment if it farts it blows the boost gauge pipe off and i hadn't done the clip up too tight to allow it to do that. Probably not the best solution but it seemed to work ok. It also encouraged me not to put my foot down when engine cold because it only seems to fart when cold and using too many revs.

Am I correct to say metro turbo ran a blowback valve? If so i think i have a box somewhere in workshop with loads of met turbo bits in it so should have one, probably a good idea to fit one really.

Brace underneath is by means of a bar bolted to bottom of manifold going to the blanking plate for where the fuel pump used to be. Its at a nice angle and I think will be all good.

At the moment i have to admit car has only done a handfull of miles with supercharger on and it wasn't all smiles, but that was before the engine build. My happy "its all good" attitude could change next week as it all goes pear shaped maybe? Or I could just be lucky as I usually am and it all comes togethor, after sorting gremlins and niggles.

Post by **bmcecosse** » Sun Feb 10, 2008 7:10 pm

No need for blow-off valve -it's a supercharger, not a turbo. And the carb throttle is on the inlet to the system. I think that's the breather connection on the carb- but they vary from carb model to model.Yes Paul - there are various alternative thermo caps which fit - mine was 50p at autojumble so no idea what it's off -but I had to run a drill through the bolt holes to get it to fit the way I needed.

Post by **matt993fod** » Sun Feb 10, 2008 8:46 pm

Nice one. I plan to fit a cortina anti roll bar to my own moggy someday, since I have the mounting points already installed, and a rollbar in the shed. I just need some spare cash for the extra insurance costs.

Post by **Matt** » Sun Feb 10, 2008 9:06 pm

I bet it wont cost any more to insure... ask the insurance company

Post by **superchargedfool** » Mon Feb 11, 2008 1:29 pm

well I have just driven it a few times round the local block and Oh my god!

There is a horrible oil leak but it is not breathing so its just something that needs sorting.

Its flat as a fart to 3000rpm then goes like stink till you change gear.

The needle BBC doesn't seem to be right, I was told it was the one Vmax Scart use but I am having to run the mixture at full tilt to nearly get enough fuel. That said it does go like hell. Tail steps out in 2nd in straight line purely on power.

85 mph came up very quickly and I slowed down.

I haven't revved it over high 4's yet cos I am trying to be sensible but it just felt stronger and stronger as the revs rise. You have to be quick to change gear as well cos it all happens so quickly.

Cooling didn't seem to be an issue but then it is winter and I didn't have the bonnet on!

I had to wrap the inlet pipe from the carb to the supercharger cos it was freezing a bit.

The whining noise with the cone filter induction roar seemed very surreal in a moggy.

I am going to resist playing with it further today and resume tomorrow.

Post by **Orkney** » Mon Feb 11, 2008 1:35 pm

you MUST get a youtube of this !
Good for you being patient and not thrashing it just yet, takes some self will that does.