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To Supercharge or not

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Jayrz

Jayrz

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Hmm,

seems I have a decision to make. Build this 1275 sitting on my garage floor to be naturally aspirated with high compression pistons and a nice cam, mildly ported head and header etc. to the tune of hopefully 90-100hp and what? $5000

or

build a motor specifically for a Moss supercharger and drop $7000 or so, for a proportionaly larger hp gain.

Pros Cons

what would you do?
 
Trevor Jessie

Trevor Jessie

Yoda
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My current supercharged engine runs out of "go" at 6000 rpm, but it makes for a FUN street car (the "go" starts at 1700 rpm). I'm hoping to build up another engine that stretches the powerband a little more.

If I had it to do again... I'd still supercharge, or do like Glenn and do a homebrew turbo except fuel injected.

However, if you will be doing a bunch of high speed driving then you might want to go NA.
 
V

vagt6

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100 HP is a very nice improvement to the stock setup. Very peppy and a significant improvement in acceleration at every speed range.

If poss, hitch a ride in a Spridget that has approx. 100 HP at the next car show. I remember a friend of mine had a Midget back in the day with similar HP mods: his Midget would haul butt and could easily outrun my modded GT6 in a straight line (not in the curves!).

IMHO, it ain't worth $5-$7,000 clams for the extra HP you get with a supercharger and upgraded systems to handle the extra power safely.

Unless money is no object, or you have a huge resto budget, of course. /bcforum/images/%%GRAEMLIN_URL%%/driving.gif
 
Trevor Jessie

Trevor Jessie

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GT6's do curves? Hmmm. Learn something new everyday.
/bcforum/images/%%GRAEMLIN_URL%%/wink.gif
 
Morris

Morris

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In my unqualified opinion, you can't beat turbo in the "bang for buck" department. But turbo will require lots of fab and experimentation to get right. Where I doing it, I would either, get everything working on a non-rebuilt motor (driving and boosting very mildly) then rebuild or, rebuild and break everything in with a set of known good carbs, then add turbo. But going with option 2 you still have a significant risk of blowing up your freshly rebuilt motor. With option 1, you blow up the motor, no big deal.

If you are not looking for a crazy project and just want a fun too drive, reliable car, I would go NA.

BTW, while I love the super charge kit in concept, IMHO it is waaaaay overpriced for what you get. It might be a worthwhile mod if it cost half what it does.
 
Trevor Jessie

Trevor Jessie

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I agree that the SC kit is too expensive, but I'm doing something similar to your suggestion. I stuck it on my "budget rebuild" engine and tinkered with it for some time. Soon I'll build up my spare 1275 to better utilize the SC. Then... maybe I'll do a turbo on my current 1275.

I enjoy the "head scratching" and tinkering as much as driving the car. The SC adds a dimension to the car that you don't get with NA motors.

The SC makes no financial sense if you are wanting a fast car. But it does make for a quick car with very different characteristics than NA ... and I enjoy those characteristics over the ultimate HP mark.
 
Morris

Morris

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:]I enjoy the "head scratching" and tinkering as much as driving the car.[/QUOTE]

Me too. Or at least I did. I am little over it right now. Too many stupid problems to run down. *sigh*

Just for the record, if I had the disposable income, I would by the SC kit in a heart beat.
 
kcbugeye1275

kcbugeye1275

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I've done the SC with a motor that is built for a SC and it is expensive, but!!!!! I can't tell you how much fun it is. As is anything, if you want it right, do it right the first time. I took it to the Ozarks last weekend and on some of those grades with the passing lanes, I did pass others by just puting the foot on the peddle and going, Everyone who has riden in it is more than impressed. My motor still pulls strong at 6,000, and I haven't really tried for any more. Now that the money is spent, I'm really glad that it is in my car. High compresssion cars are becoming more of a problem as time passes because of the gasoline situation and what will be available in the future. I really don't think there is a wrong decision, but I am telling you the potential is just a lot of fun.
 
Jim_Gruber

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If I had $5-6k of disposable inclme right now I'd consider something like a Miata Engine and 5 Speed with narrowed RX-7 Rear End. Or RX-7 and same. I'll bet you could do it less than 5k. There was a Bugeye advertised last year with a, see if I can get this right, 323GT Turbo Motor (1983-84 vintage) reinforced frame/unibody, Miata 5 Speed, and RX-7 Rear End. Scary fast at 250+ HP. P.O. said everything fit just fine, needed to mod the heater box but other than that a nice drop in swap. From the outside all looked stock.
 
P

piman

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Hello Jay,

what I understand is that the difference is in driveability, a supercharged engine is easy because of the increase in torque, and doesn't need high revs. A highly tuned engine needs a lot more driving to keep it on the power band.
Really the choice is yours as to what type of driving you want to do?
Supercharging was a period modification when these cars were new so it is in keeping with the character of the car. (Which Jim Gruber's suggestion certainly is not.)

Alec
 
Jim_Gruber

Jim_Gruber

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I agree on the period correctness of the modifications however the Moss Eaton Supercharger vs. Judson/Schrock is not period correct either. For the same $ spent you could end up with much higher performance. It all depends like all of these cars on what the owners intents and desires are to do with their cars. Everyone has a different opinion, goal. All I want to do is drive Bugsy and have fun doing it.
 
OP
Jayrz

Jayrz

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Hmmm,
thanks for the input guys. I am leaning towards a naturally aspirated motor and, really it is only because the SC is so dang expensive.

My plan is this then

*10:1 pistons,(it is a little high but this is Denver)
*mildly ported head
*276-ish cam, probably a Kent or Elgin but not too wild and man will cams start an argument!
*1.5 rockers
*SU carbs worked to Vizard recommendations on a steel maniflow intake
*LCB header

does this sound like enough to get me into the 90-100 range?
 
Trevor Jessie

Trevor Jessie

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"does this sound like enough to get me into the 90-100 range"


mmmm, I doubt it, but you left out an important detail... bore?
 
OP
Jayrz

Jayrz

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Bore?

Sorry I missed that, for a naturally aspirated motor I wanted to tak it out to 1380 since I am buying pistons anyway. SpridgetMania has pistons to get the 1275 to this displacement.
 
jlaird

jlaird

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Improve the exhaust manifold as well, it has to breath.
 
OP
Jayrz

Jayrz

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Not enough cam,,,,

well I am afraid of losing the enines streetability, are my goals to high for a streetable engine?

If someone could lay out exactly how the datsun A14 fits I might be tempted to go that route but no one seems to have templates of mounts or even any pictures I can look at to see if it is something I want to dive into.

What to do what to do,,,,
 
Glen_B

Glen_B

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Read up in Vizard before you go 1380. Boreflex and blowby are issues of concern. If you go .060 over, with the right pistons/cam/carb/tuning, you can get to a happy place with the aforementioned problems.

Glen Byrns

(Go turbo!!)
 
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