TR2/3/3A Moss Supercharger for TR3A

[Guest]

Hahaha, I wouldn't want to go there in one of these things much less stick around.

 

[60TR3A]

Just because the majority of my driving around Sanibel Island is under 35 MPH doesn't mean I won't have other opportunities to drive it up to 70, so if I can get that kick in the pants whenever I want it, it's money well-spent.

Off the line I don't expect to get much of anything but wheel spin because for whatever reason, my 3.70 rear end breaks the right rear tire loose all the time and I chirp it unwittingly. I don't mean to, it just happens more often than I'd like so any boost the S/C will give will have to be once I'm under way and above 10 - 15 MPH in first, and it should be a lot of fun in second and third when I'm off-island and able to air it out a bit.

I'm not looking for nitrous power: I'm looking for more everyday, reliable acceleration to make it more fun at any speed. If I want raw acceleration, I have a supercar for that already: 2011 R8 Spyder V10 with an old school gated 6-speed manual.

 

[Guest]

I have a supercar for that already: 2011 R8 Spyder V10 with an old school gated 6-speed manual.

Oh, you have ~too~ much money. :laugh:

Why didn't you say so before! :thumbsup:

Yes, get the s/c and some type of locker, quaffe or torsen for the diff.

I don't know what's avalible for the 3, but might as well put all that new power to the ground.

 

[60TR3A]

You can't have too much money. It's like saying you have too much horsepower.

Getting the S/C isn't a money question, just one of practicality and whether or not it'll blow up my engine. I don't want to ruin a perfectly healthy motor, but if blowing it won't hurt it, then I'm going for it!

 

[tinman58]

I feel the same way! Drive for fun, the sound of the s/c has got to be cool as the looks of it in the engine compartment....

 

[60TR3A]

I feel the same way! Drive for fun, the sound of the s/c has got to be cool as the looks of it in the engine compartment....

I'm hoping it makes a nice, loud whine. My wife has an '06 Jaguar XKR convertible with a blown V8 which makes the most wonderful-sounding whine!

 

[tdskip]

So long as you don't crank the boost up and the engine is otherwise healthy I'd expect it will be fine. Supercharging is a nice way to go since it is pretty seamless unlike most bolt on turbo kits (based on experience w/ both but on much more modern cars. Had a Jackson Racing supercharger on my Miata. Very nice difference)

 

[swift6]

I'm especially interested in acceleration in first and second and in the lower speeds as I rarely take the car anyplace where I get up to highway speeds, so 0-45 MPH is where I want to feel the added power.

The above is what I was basing my comments on. From Darrel's experience your not going to see much in the 0-20mph range but will in the 20-45mph. Once you get it off the island there would be more to be had but very little for the money in that 1st and 2nd gear use as stated.

TR3Driver pointed out some other real world testing. The lightened flywheel and the higher gear to make more use of the torque and spend more time in gear accelerating, putting the power to the ground instead of spinning the tires. That would also result in a few less rpm's when you make it off the island and can go beyond 45mph.

Of course, since money is no object, why not do it all?

 

[60TR3A]

If I gave the impression that money is no object, then I misspoke. Just because I can afford it doesn't mean I want to spend $10-grand on a $23-grand car. It's a slippery slope once you get into the mentality of, "Well, since I'm already there, might as well do this and that". Once I go ahead with the idea of a lightweight flywheel, since I'm already there I might as well open the gearbox and replace the slow and tired synchros; and once the box is open if it's possible to add synchromesh to first, might as well do that (is that even possible to add syncho on first in a tranny that was designed not to have it?); and since I'm there I might as well check the clutch and replace, if needed; and since the apron is off, might as well replace the radiator and upgrade the fan; and so on. Before you know it my $5K project has just doubled in cost. I've already overspent on bling for my car as it is, and I don't expect to make it into something actually quick; I just want to add some oomph and I think the Moss S/C is the way to go, but I don't want to go down that slippery slope of "Since I'm already there"...

 

[Darrell_Walker]

I should clarify, I don't think there is much benefit in boost from about 0-20, just because there isn't enough time before you shift. But my car is more responsive even down there, I suspect for the same reasons that it seems to idle better and lower. I suspect something to do with the length of the intake, etc.

I do have an alloy flywheel (and had be before the supercharger). That, and getting rid of the mechanical fan also made a noticeable difference, but not as much as the supercharger.

There is a bit of a sound from the supercharger, more of a suction sound than a "whine", and when you get up in RPMs, it really sounds sweet.

 

[martx-5]

The blurb that Moss gives is that the supercharger will increase the power by 40%. That means you will be going from 100HP to 140HP. That is a very large jump for a bolt on accessory. I have an Eaton on my Miata (from Moss also), and it also gives a 40% jump in HP running at 5-6 psi of boost, which is what it takes to get that increase. My son also stuffed an Eaton on a VW GTi that he once owned, and it also gave that 40% increase at 6 psi of boost. All I can say is that the first time you get on it, the first word out of your mouth will most likely be <span style="font-size: 12pt"><span style="font-weight: bold">"WOW"!</span></span>...or something to that effect. The power is linear. It's like you stuffed a larger engine under the bonnet.

If the supercharger was available before I got into rebuilding the engine in my TR3 where I went the conventional route of cams and compression increase, I definitely would have gone the blower route, even though it would have cost twice as much. What you have is an engine that is totally stock and docile until you get on the loud pedal and into boost.

I would however seriously consider some form of ignition module to back off the timing when in boost, otherwise you will have to back off the initial timing 4-6 degrees, and that will result in the engine feeling lazy until you get into boost. I have such a unit on my Miata, and it makes a big difference.

Anyway, have fun with it. Ya gonna like it.

 

[60TR3A]

OK, I heard from Moss tonight. They actually have a special part number for TR3s with 83mm cylinders due to the difference in compression ratio versus cars with 86mm cylinders so my question then is: "How do I determine what size cylinders I have short of pulling the head and measuring?" I wouldn't want to order the unit made specifically for the smaller bore engine if I'm not certain that's what I have under the bonnet.

They also say that all the parts are in-stock except for a special pulley required for the 83mm engine which requires a 6-week lead time. Once I know for certain what size pistons I have, I'm ready to place my order. Any & all suggestions how to determine my piston size short of removing the head are welcome.

 

[Guest]

. That means you will be going from 100HP to 140HP. :

3's put out almost as much as a US 6?

I can see a pulley difference but not a different s/c. That makes sense.

 

[Darrell_Walker]

They also say that all the parts are in-stock except for a special pulley required for the 83mm engine which requires a 6-week lead time. Once I know for certain what size pistons I have, I'm ready to place my order. Any & all suggestions how to determine my piston size short of removing the head are welcome.

No great ideas on how to measure that without pulling the head.

You could just put on the standard kit, and see how much boost it generates. If it is more than 5 psi or so, then consider getting the larger pulley for the blower.

I actually have the big boost kit, but have not installed it yet.

 

[60TR3A]

Actually, Moss advised me that the big boost kit isn't available for the 83mm cylinder blower. Could it be that the smaller bore engine already has higher compression and thus over-boosting might be too stressful on the engine? Maybe the best bet is to err on the side of caution by assuming my engine is original and to order that blower.

As for the idea of installing a lightweight flywheel, my mechanic says it'll be very pricey - 25 hours - so that's off the table entirely. If ever I need to rebuild the transmission perhaps then I'll do it but for now I'll just go with the blower and an electric fan and eliminate the mechanical fan.

 

[Darrell_Walker]

Actually, Moss advised me that the big boost kit isn't available for the 83mm cylinder blower. Could it be that the smaller bore engine already has higher compression and thus over-boosting might be too stressful on the engine? Maybe the best bet is to err on the side of caution by assuming my engine is original and to order that blower.

The big boost kit is just a smaller pulley for the blower, so that it spins faster. I'm assuming the special 83mm kit is just a larger pulley, so that the blower spins slower in relation to the engine?

As for the idea of installing a lightweight flywheel, my mechanic says it'll be very pricey - 25 hours - so that's off the table entirely. If ever I need to rebuild the transmission perhaps then I'll do it but for now I'll just go with the blower and an electric fan and eliminate the mechanical fan.

That seems high, though I've only pulled the transmission in a 4A, but I thought it was basically the same. Did he plan to pull the engine? Changing the flywheel with the engine in the car shouldn't be too difficult. Not the most fun, but certainly a reasonable job (again, at least on the 4A).

 

[TR3driver]

25 hours seems way high to me, too. It's basically the same as the 4A, except you don't have to disassemble the center console. ISTR last time it took me about 3 hours to get it out, and maybe 4 or 5 to go back in. And I'm not a particularly fast worker.

For checking displacement, ideally you want something like a big burette. But they are kind of pricey, not worth buying for a single use
https://compare.ebay.com/like/370525397570

Probably you could get close enough though with just a rubber tube coupled to the spark plug hole, and a 500 ml (1 pint) measuring cup. Turn the cylinder to BDC and fill it with oil through the tube, working the piston up and down a bit to expel all the air. Then turn the end of the tube down and let the oil drain to the level of the bend in the tube. Hold the measuring cup under the tube and have someone else turn the cylinder to TDC while you hold the tube steady and catch the oil. If you get more than 500ml, then you have 86mm liners (or larger).

 

[60TR3A]

For checking displacement, ideally you want something like a big burette. But they are kind of pricey, not worth buying for a single use
https://compare.ebay.com/like/370525397570

Probably you could get close enough though with just a rubber tube coupled to the spark plug hole, and a 500 ml (1 pint) measuring cup. Turn the cylinder to BDC and fill it with oil through the tube, working the piston up and down a bit to expel all the air. Then turn the end of the tube down and let the oil drain to the level of the bend in the tube. Hold the measuring cup under the tube and have someone else turn the cylinder to TDC while you hold the tube steady and catch the oil. If you get more than 500ml, then you have 86mm liners (or larger).

As always, I can count on you, TR3Driver! Damned clever of you to come up with that idea!

 

[martx-5]

...

3's put out almost as much as a US 6?

In a word, yes...and because the TR3 is lighter, they are generally a tad faster.

 

[60TR3A]

The die is cast and the deed is done: I ordered the Moss blower for smaller pistons. I'm shipping the car next week up to VT so there's simply no time to pull the head to measure the pistons and my mechanic is quite confident the engine is original and probably has the 83mm pistons; worst case is we don't get adequate boost and he'll switch pulleys. I.O.M.

I won't have the car back in FL until early Nov., so I'll pick up this thread then and give you all a report of the final results. Thanks everyone for your help and advice and encouragement.