Is the Answer a $100 supercharger?

In reply to Mr. Lee :

Still waiting for it to fully click for me... I'm getting there.

Could the issue just be resolved with a blow off valve like most turbo cars have?

That would have been my thoughts as well, why not a blow off valve in a supercharger installation? 

Two throttle bodies:

One throttles the supercharger. This is the most important one. If you don't have it there, you need a really big blow-off valve or it will blow your IC tubing apart as the SC tries to ram as much air as possible down the intake tubes all the time. The valve will be open most of the time as it bleeds off air the engine doesn't want. You will also found that YOUR SUPERCHARGER IS REALLY LOUD ALL THE TIME. Seriously. They howl.

The second one is optional. It's in the stock location, and it's there to make idle control easier as you're dealing with a much smaller column of air. If you try to control idle with the pre-SC TB on a system with an air/air IC, you have a big lag between the request for more/less and the result due to the amount of throttled volume. It's most obvious when you're coming up to a stop and you go from light throttle to idle, the system can't react and go into idle mode fast enough to prevent a big drop in engine speed or stall. This is why you'll see a lot of SC setups running a high idle - or running on a custom intake manifold with an integrated air/water iC.

In reply to Keith Tanner :

Ahhhh, it clicked now! Makes sense since the super charger is building boost all the time vs a turbo which is only under load. Thanks for explaining that!

One of the reasons why Mercedes used the electric clutch on some of their cars.

The drawback being they are complicated and prone to failure, so they obviously added the bypass as a more reliable solution to avoid some of these issues.

I suspect they may also use the VSS to help with the idle droop as many companies have done since the 80's (Chrysler did this on their cars in the eighties, plus they changed the cooling fan scheduling depending on vehicle speed).

I'm curious. Can anyone thing of a production positive displacement supercharger that uses an air/air IC?

The Mercedes SLK230 Kompressor, which had either an Eaton M62 with an electric clutch or an Eaton M45 with a bypass.  Both were Air/Air Intercooled.

Eaton M62:

How many throttle bodies? I figure that every positive displacement SC has a bypass.

In reply to Jack Heideman :

I’m waiting to see how your experience with E85 goes. All that alcohol should do a great job of cooling the charge since it’s turned to vapor right ahead of the way intake  valve. 

The difficulty is a way to measure the cooling effect. 

I know how real it can be. Years ago on a really cool nights  we’d get rough running  because the intake valve would freeze up. However we were running 100 % alcohol  not 85% 

Plus if you are using pump fuel that E85 can be anywhere from 51% to 83% alcohol  and still be sold as E85. So likely freeze up won’t be an issue. I know you can buy real E85 from race gasoline dealers but it’s a lot more expensive than what is sold at the pumps. 

I’m not sold on the need for an intercooler if you are using E85.  GRM did an article on air flow and two things were made very clear.  

One.  airflow decreases  with every bend.  

Two. The longer the tube the more airflow loss. 

My own addition is an intercooler has a combination of both of those.  

I’m not saying an intercooler is bad, or not needed. I just question the need if E85 is used.  

In reply to Keith Tanner :

One throttle body, they used an internal, vacuum operated bypass.  It just looks a lot like a throttle body :)

Keith Tanner said:

I'm curious. Can anyone thing of a production positive displacement supercharger that uses an air/air IC?

R53 MINI CooperS ?

Thanks for the better explanation of the dual throttle bodies Keith!

Frenchyd,

As far as the E85 goes its more than just the fuel burning cooler. It has more oxygen in it than gasoline and has a higher octane than pump gas. Im hoping to add more timing in once I get it setup.

I have almost everything done on the E85 conversion but I haven't been able to get a reading from the sensor in the Meagsquirt. Im hoping to work on it more in a couple weeks once school is done.

In reply to Jack Heideman :

You are absolutely correct.  I understood that but I’m doing my best to make my comments and questions more like comments and questions then the long winded lectures I’ve so often been guilty of. 

Amazing work! Thank you for all of the photos.  Any chance you'd share the file of your adaptor plate base? :-)

Its been a while but here's the update on my new belt setup!

As mentioned before, in my first belt literation I placed the tensioner on the tensioned side of the belt instead of the normal slack side. This worked for a while, but after a couple hundred miles the belt started to slip.

After a little time staring at the engine I realized I could mount the tensioner to the upper blower mount. Here's it tacked in place.

I couldn't get the GM tensioner to keep from maxing out its angle in the new spot so I added an idler below it. It just so happens that an old Miata timing belt idler fits perfect when sharing a bolt with the power steering pump bracket.

I ran into some belt alignment issues once I first started the car. I kept moving the belt tensioner, but no matter what I did I couldn't keep the belt from flying off. I used the ruler trick shown before to get the tensoner as close to square as possible and the belt still wouldn't stay on. After some trial and error with shims I found the sweet spot and the belt has stayed on ever since.  

Here is the final setup.

Wesmc, I'll gladly share my cad file. PM me your email and I can send it over.

Keith Tanner said:

I'm curious. Can anyone thing of a production positive displacement supercharger that uses an air/air IC?

Thunderbird Supercoupes had an air/air intercooler

Excellent work  Jack!!! is there possibility of you  posting a link to your Cad file  on a sharing platform ....seams i cannot send a PM ...

i've been looking at ways  to boost my miata ... this thread is one of the best that i have come across

thankyou for sharing your ideas and work to the comunity.

Stefan said:

The Mercedes SLK230 Kompressor, which had either an Eaton M62 with an electric clutch or an Eaton M45 with a bypass.  Both were Air/Air Intercooled.

 

The couple setups I built used bypass valves and I was pretty happy with how they worked. ....it makes the system silent when your at low throttle, fuel mileage on the highway where I was off the throttle was as good or better than stock and most importantly idle was smooth and stable vs wanting to surge without the valve.

In reply to mke :

So I haven't updated in a while but I have been driving the car a fair amount.  I would like to add in a bypass valve at some point. The noise from the blower is starting to drive me crazy.

Other than the crazy whining the supercharger setup is still holding up great!

In reply to NBjb :

I can but the file is on my old laptop. I won't be able to get to it for atleast another week or so.

thanks Jack..... im still working on my setup ....may go with the eatons mini cooper R53 route... but i also have same Merc m45 and a Merc M62 with a dead electronic clutch .... was too cold last winter in the garage to modify and now with Covid 19 has put the  brakes on things.... ironing things out on the megasquirt ecu....theses days....

be safe ....everyone!

In reply to NBjb :

I like the idea of the Mini Cooper Supercharger. the internal bypass valve would be nice. The Mercedes one was cheap and easy for me to get at the time.

Hey Jack,

Awesome work! Any way you could share your CAD files as .STEP? I'm looking to do something very similar.

In reply to beersaj :

Yes, DM me your email and I can send it.

In reply to Jack Heideman :

Email sent