I heard somewhere that higher compression gives a little better MPG. Is this true? I've also heard that if I go with a S'charger, then I can use a little higher compression and get good MPG.
So here's my proposed plan. I'd appreciate all input!
Super Ram intake, 383 stroker crank, stock bore (to raise compression) with new pistons and rods of course, Vortech Supercharger, AFR 190cc heads, on an LT1 with T56.
Opinions please.....sounds like a good plan?

This is my daily driver, so MPG and streetability is a concern!

 

You want your compression ratios to be lower for super and turbo charged applications. Theoretically the higher the CR the higher the engine efficeincy. However this is limited by petroleum fuels for street cars. It really depends on a number of factors but in its most non technical form you are right.

 

Oh ok, thanks man. So would that setup work well with a CC305 cam and N/A? I'm really looking for around 400HP and 15-17 city, and 20-25 highway gas mileage wise. You think this setup would get me close to that?

 

A higher CR will make the engine a bit more efficient, making for better milage. For a forced induction system though, you need to drop the CR to make it useable on pump gas.

If its for a S/C, I would start at around 8.5 CR.

 

Thanks for that info guys! So which would be better on gas and possible to get 400HP: N/A or S'charged?

 

One or the other.. SC is more expensive..
400hp u get with (example) vortecs, airgap&750 cfm carb,
hotcam and 1 5/8 headers.. 440hp with the xe 274.

Better on gas, I guess supercharged since its not always producing boost ... but $$$

 

So even though the S'charger is most expensive in the long run, would it possibly get better MPG with a T56 than a 383? I'm looking at Lloyd Elliot's heads/cam packages and a Super Ram....

 

When you get the super ram make sure to get the dfi with it. Than TUNE. Right now I have a super ram, 9.25:1 CR, LT4 hot cam, forged 355, SLP 1 3/4 headers, AFR 195's flowing 288, etc... We are looking to be in the 26-29 range with DFI as far as MPG. Should be right around 425-450hp wise.

With that CR I plan on running a "stock" ATI procharger built for a stock TPI. Should be fun, and will keep close the same gas mileage. ATI actually says gains can be made in that area too... Not sure what I think about that, but I should be able to run a lower octane and get better mileage without detonation. Remember a stock l98 is 9.5:1 and I am at 9.25:1

 

Well when I get the Super Ram, It'll go on my LT1, so I'll use the LT1 computer...tuned of course. Not sure how much difference this will make.

 

Um quick thought. Why are you going to choke that LT1 by going to a Super Ram? Anyone will tell you that the LT1 intake will outflow the super ram. Much better intake. I just cant do it due to emissions here in california. Super Ram is your best choice, if not one of your best choices all around anyway, for an aftermarket intake for a emissions car in cali, but the LT1 is better.

 

Super Ram produces outstanding torque low down. I do realize the LT1 flows better up top around 6000+ but I won't be revving that high on a regular basis. This is my daily driver, so I need low-down torque more than top-end power.

 

Every dyno sheet I have seen shows the LT1 making more low end torque than the Super Ram... But hey I have the Super Ram, so Im certainly not going to knock your choice

 

Getting a little old hearing about this "down low" torque thing of the TPI's and superram, the LT1 will make more in the bottom of the curve than you can plant on the street either way, you'd be making a shoot yourself in the foot move by spending a chunk of change on an intake you *think* is going to help you but in the long run just hurt you.

You say a vortech supercharger, but you do realize there isnt a vortech kit that will bolt right onto your motor in the car right ? that would have to be custom fabbed, i'd say go for around 9.5:1 and powerdyne has a kit for the impala SS that should give you no fitment problems.

 

Well I'll be using the a ported LT1 intake to start off getting the car running. Then after I get everything dialed in a working properly, I'll invest in a Super Ram. I'll take it to the dyno and to the track and personally compare both intakes and see which is better. I have to see for myself. Oh and thanks for the info about the S'charger. I'll check it out. Back to my original question, what's the best engine combo that'll get the mileage and power I want?

 

Lt5 / LS6

 

lol...if I had the $$$..LS6 would be kick ***!