MGExp

MG Midget Forum

DIY supercharger option - with EFI!!!

Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

1974MGMidget Avatar
1974MGMidget Silver Member Jack Orkin
Grayson, GA, USA   USA
Rather than paint that pretty piece, just hold a rag with some polish on it with the engine running and shine that sucker up!
Will the crank pulley have an integral damper?

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
In reply to # 3679174 by mster50 You'd think belts would not be that difficult. There is a lot there, good job.

Mike,

Yup, deceptively challenging. But the nut of it has been trying to arrive at a system that incorporates all the best attributes: a single belt, the least expensive setup, a system that requires no extensive fabrication and only common hand tools. Then there's the (in my opinion) barely adequate and over-priced Moss pulleys--the only ones available right now.

What I've done is work with Smooth Flow to design and market a 5-rib (Moss's is 4-rib) A-series H2O pulley for much less money, and designed my own 5-rib crank pulley, again for substantially less money and featuring superior machining, frankly (lots of machine chatter and sharp ribs, etc., on the existing option). The idler pulleys I've found are > $30 for the pair, and the belt something like $18. The last piece of the puzzle--desirable but not absolutely necessary--is a spring tensioner, which I hope to tackle today or next weekend, as the Subaru dealer stripped my Outback's drain plug, so a 30-minute job turned into a 2-hour job with trips to town for an aftermarket plug...

Joel


Member Services:
Innovative DIY performance and reliability upgrades.
Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
In reply to # 3679224 by 1974MGMidget Rather than paint that pretty piece, just hold a rag with some polish on it with the engine running and shine that sucker up!
Will the crank pulley have an integral damper?

Jack,

Yes, that's certainly an option! I may end up doing that, but then one has to police the finish, as bare aluminum will start oxidizing instantly... we'll see. Hmmm... maybe I could clear-coat it...? cool smiley

Oh, sorry - no dampener. None of the aftermarket aluminum crank pulleys I've seen have them, and the auto machine shop I've chosen to do the bottom-end machining for my forthcoming rebuild say in their experience they don't do much. This is especially true where an engine is properly balanced, they tell me.

Joel



Edited 1 time(s). Last edit at 2018-02-11 01:30 PM by Yankeedriver.


Member Services:
Innovative DIY performance and reliability upgrades.
1974MGMidget Avatar
1974MGMidget Silver Member Jack Orkin
Grayson, GA, USA   USA
Oh, sorry - no dampener. None of the aftermarket aluminum crank pulleys I've seen have them, and the auto machine shop I've chosen to do the bottom-end machining for my forthcoming rebuild say in their experience they don't do much. This is especially true where an engine is properly balanced, they tell me.

Interesting. Well, there is another custom piece for you - an aluminum crank pulley for V-belt for future rebuilds!

Denis Avatar
Denis Denis Hill
Bearii, Nth Victoria, Australia   AUS
Joel I am of the opinion that a balancer is not as necessary with the supercharger. When you think about it a harmonic balance is there to dampen out "twist" harmonics in the length of the crankshaft. due to the front cylinders twisting the crank on the power stroke where the back cylinder hardly at all. All the drive load is from the rear of the crank and the damper weight is there to relieve these oscillations. On the SC engine the driving load of the blower, both boosted and un boosted, is from the front of the crank, acting the same as, and probably even better than a damper.
Denis



68 B roadster, Daffodil yellow, supercharger, Burgess SC head, SC cam, Mikuni HSR 48 carburetor and engine built for supercharging.

73 BGT V8 conversion starting with a bare shell. Built the engine early in 2016 with high comp pistons and a few other nice bits. Started on the body late 2016 and found Its a lot of work and expense starting from scratch. Did the work myself, mechanical, body. paint etc all except the interior trim.
Finished and going well, great to drive and quick. Now has a nice 3.07 LSD.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
In reply to # 3679611 by Denis Joel I am of the opinion that a balancer is not as necessary with the supercharger. When you think about it a harmonic balance is there to dampen out "twist" harmonics in the length of the crankshaft. due to the front cylinders twisting the crank on the power stroke where the back cylinder hardly at all. All the drive load is from the rear of the crank and the damper weight is there to relieve these oscillations. On the SC engine the driving load of the blower, both boosted and un boosted, is from the front of the crank, acting the same as, and probably even better than a damper.
Denis

Denis,

Fascinating. Well, that would explain why the aftermarket pulley-makers don't typically include them--assuming they did the analysis you've done. Regardless, it makes sense to me. As I may have said, my machinist is in the hospital, so we're in limbo on the crank pulleys until that situation works itself out--I hope in a positive way.

Joel


Member Services:
Innovative DIY performance and reliability upgrades.
Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
In reply to # 3688653 by shynsy Agree regarding the intercooler.. a lot of guys over here run the Moss kit for the TR6 but because all the heads over here are HC (many have CRs > 9.5:1) they are always on the edge of detonation.. something that is made a lot worse but he suck through nature of the system.. many are playing with methanol/water injection to cool the charge but it is a bit of a faf.

Hoping that reducing the CR on mine will make things simpler. (Ironically I had at get an LC cylinder head that had been reimported from the US into the UK. This means it was originally manufactured at the triumph works in Canley, which is 2 miles from my house, exported to the US in 70's and then re-imported. To complete the circle the head was rebuilt by a company 10 yds from the original Canley site..)...

At the moment I am aiming to enjoy the midget as normally aspirated, but I know I will get bored and want to pep it up so maybe a SC.. Although over here it is more normal to fit a 1.8 K-series engine, the you have up to 170 BHP to pay with..
Cheers
Tim

Tim,

As you'll read in this very long thread, those with draw-through kits do generally run lowered compression ratios, and at least one of them has experimented with H2O injection to cool the charge.

I'm hoping the intercooler will allow a bit more boost--though initially, anyway, I'm starting with ~7 psi. As I'm about to report in the next post, I may ask my machinist to make a slightly larger crank pully to enable higher boost levels for those so inclined.

Joel


Member Services:
Innovative DIY performance and reliability upgrades.
Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
**Update: my machinist called me yesterday, and although not out of the woods, he's out of intensive care and wanted to set up a meeting to green light the 5-rib A-series crank pulley.

We'll be meeting today or tomorrow, Monday if he's too worn down by his first week of being back in the shop. He and I have come up with a couple of options for locking down the bolt that holds the pulley on, and which don't require an additional set-up to machine the depression for the big washer. This makes a surprising difference in the price point, which I'm trying to keep as low as possible.

So, we'll finalize those things, and as I mentioned in the above post to Tim, I'm thinking of making the pulley diameter slightly larger than what Moss settled on, as that would enable higher boost levels. One can always put a larger pulley on the blower (Nate at Smoothflow will make any size you want), but eventually one runs out of room going smaller.

Should have a prototype crank pulley cut fairly soon, and this weekend I hope to finish the prototype front blower mount. I'm now thinking that I'll have a couple of dozen front mounts laser cut to save folks the trouble of fabricating them. It's not hard to do from a technical standpoint, but not everyone has a drill press, etc. So, the first run will be around 9~10 kits, consisting of: M45 adapter, 5-rib crank pulley, and HIF44 adapter (unless one already bought one or is going EFI). Everything else is available on the web or easily made up by a DIY'er with ordinary hand tools.

Joel


Member Services:
Innovative DIY performance and reliability upgrades.
pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, NS, Canada   CAN
Water injection is quite effective. I installed it and it did the job but then I lowered my compression from 9 to 8:1 and found I no longer needed it.

Adrian



Home built Eaton M62 Supercharger with 9psi boost, "stock" high ratio rocker arms, 8:1 compression, Piper 270 cam, ported head, matched manifolds, CB Performance computerized ignition.

Denis Avatar
Denis Denis Hill
Bearii, Nth Victoria, Australia   AUS
By 2 what Adrian said, Water or water/Methanol is great if detonation is a problem. It wont make horse power in itself but will allow you to run closer to ideal advance. Its simple , trouble free and great if your compression is a little higher than ideal.
Joel I dont know what your SC drive ratio is but its worth remembering, that in most cases changing the SC pulley dia gives a bigger increase in ratio than the same amount on the crank ( depending on the amount of overdrive)



68 B roadster, Daffodil yellow, supercharger, Burgess SC head, SC cam, Mikuni HSR 48 carburetor and engine built for supercharging.

73 BGT V8 conversion starting with a bare shell. Built the engine early in 2016 with high comp pistons and a few other nice bits. Started on the body late 2016 and found Its a lot of work and expense starting from scratch. Did the work myself, mechanical, body. paint etc all except the interior trim.
Finished and going well, great to drive and quick. Now has a nice 3.07 LSD.

Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
Dear Denis and Adrian -

Thanks, gentlemen. Water and/or methanol injection seems to be an effective measure with the draw-through configuration, where that's the only way to reduce the temperature of the intake charge (other than re-plumbing with a snorkel to move the air cleaner ahead of the radiator, under the fender, etc. That's one purpose of the SU HIF44 adapter I just came out with).

However, one chief benefit of the intercooler enabled by the blow-through setup is that it allows a substantially higher compression ratio without a similar risk of detonation. The intercooled Mercedes SLK230 from which I take the M45 Eaton blower has a compression ratio of 9:1. My wife's intercooled Volvo C30 T5 has a ratio of 9:0. It will be very interesting to see how much advance my stock 1275 (and others who have said they're going to do this conversion) will handle before exhibiting any detonation.

Denis -

You're totally right--and I'm really glad you brought that up. I need to balance the limited benefit of increasing crank pulley diameter with potentially complicating removal of the engine. I'll be sure and do the math and see how much the ratio is affected for [x] increase before having the machinist cut a pulley any larger than the stock V-belt pulley. I'd hate to make what is already a very tight squeeze even more of a headache!

Joel


Member Services:
Innovative DIY performance and reliability upgrades.
pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, NS, Canada   CAN
You can do an intercooled draw through setup. I believe we discussed this earlier. Mercedes, BMW Mini, etc. are draw through setups with intercoolers. If the throttle is ahead of the blower, it's draw through. They accomplish this by using EFI to keep the intercooler "dry". I think you could do it with an SU by removing the throttle disc... just not sure about the idle circuit. It would be an interesting experiment.

My own car had 9:1 compression at 9psi boost on water/meth injection. I found I used quite a bit of water/meth though. One tank of w/m to one tank of gas. I have a heavy foot. Cheaper and less "faffing about" to lower the compression. The loss of compression was offset by a larger charge in the chamber.

Adrian



Home built Eaton M62 Supercharger with 9psi boost, "stock" high ratio rocker arms, 8:1 compression, Piper 270 cam, ported head, matched manifolds, CB Performance computerized ignition.

Denis Avatar
Denis Denis Hill
Bearii, Nth Victoria, Australia   AUS
Adrian a 3L tank of W/M lasts me a several months, It only comes in above 5lb boost, at 180 mlpm, so some trips might use zero. I am getting too old to spend a lot of time over 5lb, things happen too quick. Like you I dont need it now with the lower compression but its there and doing no harm in our extremes of temperature. Denis



68 B roadster, Daffodil yellow, supercharger, Burgess SC head, SC cam, Mikuni HSR 48 carburetor and engine built for supercharging.

73 BGT V8 conversion starting with a bare shell. Built the engine early in 2016 with high comp pistons and a few other nice bits. Started on the body late 2016 and found Its a lot of work and expense starting from scratch. Did the work myself, mechanical, body. paint etc all except the interior trim.
Finished and going well, great to drive and quick. Now has a nice 3.07 LSD.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, NS, Canada   CAN
Denis,

I think we have the same meth tank. I've never gone on a trip that didn't use boost on nearly every up shift of the gears. The meth was costing me a fortune. I'm an acceleration junky.

I left all the water injection gear in place in case I get the boost up too high again...

Adrian



Home built Eaton M62 Supercharger with 9psi boost, "stock" high ratio rocker arms, 8:1 compression, Piper 270 cam, ported head, matched manifolds, CB Performance computerized ignition.

Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
In reply to # 3689550 by pinkyponk You can do an intercooled draw through setup. I believe we discussed this earlier. Mercedes, BMW Mini, etc. are draw through setups with intercoolers. If the throttle is ahead of the blower, it's draw through. They accomplish this by using EFI to keep the intercooler "dry". I think you could do it with an SU by removing the throttle disc... just not sure about the idle circuit. It would be an interesting experiment.

My own car had 9:1 compression at 9psi boost on water/meth injection. I found I used quite a bit of water/meth though. One tank of w/m to one tank of gas. I have a heavy foot. Cheaper and less "faffing about" to lower the compression. The loss of compression was offset by a larger charge in the chamber.

Adrian

Adrian,

Yes, one could do an intercooled draw-through setup--thank you for reminding me of that. However, the point of my remarks re: the compression ratios of the wife's Volvo C30 T5 and the Mercedes SLK230 from which I sourced the blower for the present project was to point out one significant benefit of this particular blow-through DIY conversion.

In short: owners of A-series-powered cars--and in similar fashion, a host of other British cars like Tim's TR6--will be able to supercharge their vehicles without having to rebuild their engines to lower the compression ratio or resort to water/meth injection.

Not only will this conversion be substantially cheaper than the existing kits--$4,000 for Moss's kit and $7,000 for the Aussie option discussed earlier; it appears that in all likelihood there will be no need to invest the time or money in new pistons.

Joel


Member Services:
Innovative DIY performance and reliability upgrades.
. Hide banner ads & support this website by becoming a > Gold Supporting Member <

To add your reply, or post your own questions




Registration is FREE and takes less than a minute!


Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster