Non-Turbo High Comp Upgrade

[mharrison]

What can you do with these cars with a standard N/T Upgrade?

I'm exploring the possibility of Headwork, Bore cylinders out, Oversize hig compession pistons, bigger throttle body, etc.

I know with high compression I would never want to turbo this, so that's OK.

-Matt

 

[kelvinb]

what are you looking to do with the car? you will be no where near the amount of power with a turbo compared to leaving your car n/a. you can turbo and be reliable if that is a concern, just make sure all fluids are good and you are not detonating

 

[dr1665]

What can you do with these cars with a standard N/T Upgrade?

A lot, but close to $5,000 later, you're still not going to be making more than 200hp at the wheels. Food for thought.

I'm exploring the possibility of Headwork, Bore cylinders out, Oversize hig compession pistons, bigger throttle body, etc.

Headwork = very yes.
Bore cylinders out = only the minimum to ensure concentricity. No worthwhile gains to be had from increasing displacement from 1997cc to 1998cc.
Higher CR = 4% gain per point you increase compression. Stock is 9.6:1. 10.5:1 will knock when temps are high (ambient air temps ~ 90*) on 91 octane. Anything higher than that and you sacrifice drivability.
Bigger TB = increase in throttle reponse, mostly. Ideal size is 56mm, so boring the stocker is viable alternative.

I know with high compression I would never want to turbo this, so that's OK.

You can boost 10.5:1, but it's going to be tricky.

 

[mharrison]

At this point I'm just exploring my options. I think seeing what I could get out of the 420A would be fun, but I'm not sure how much I'm willing to pay for that fun

I'm in the middle of a stock rebuild right now and am planning on building another engine on the stand as time and money permit.

 

[miklaver]

i am running 10.5 :1 and run 93 octane and have no prob. talking with Hahn i should be able to run 10 to 12 psi and port fueler and be just fine. the benefit of higher comp. is off boost you will have great power and fuel economy.

 

[VelocitàPaola]

How do you figure you get better fuel economy with higher compression?

 

[miklaver]

higher compression cylinder could produce better power and fuel economy because the same charge is squeesed harder and resulting combustion pressure is increased. but also the higher expansion ratio allows more energy to be extracted from the original higher pressure charge.

 

[dr1665]

higher compression cylinder could produce better power and fuel economy because the same charge is squeesed harder and resulting combustion pressure is increased. but also the higher expansion ratio allows more energy to be extracted from the original higher pressure charge.

Bingo.

 

[VelocitàPaola]

higher compression cylinder could produce better power and fuel economy because the same charge is squeesed harder and resulting combustion pressure is increased. but also the higher expansion ratio allows more energy to be extracted from the original higher pressure charge.

Huh... I never thought about it like that. But I bet your savings from that better fuel economy goes right out the window when you're paying $3.25/gallon for 93 octane gas.

 

[miklaver]

true that! but for me to run 8 psi with 10.5:1 is like running 13 psi at 8.8:1 and we will both have about the same but the 8.8:1 will have more room to play with boost. to figure out the boosted comp is (boost/14.7)+1 X compression ratio. also with running less boost and making the same hp you put less stress on the turbo. but harder to tune.