New Motor Question

[SMOKD U]

OK, we all know that it will either be a kennebell or vortech blower combo but here is the question

What's the best compression ratio or what have others done? I know that most people are in favor of running more boost and less compression lets say 8.5 to 1 (20 plus lbs of boost) but I have also heard of people running more compression 10. to 1 with less boost going as fast or faster.

My set up at this point is figured at 9.25 to 1 but I can change this week yet if I want to. Rick at Anderson ford likes 9.2 up to 9.5 to 1.

I know that less compression means less octane gas or more boost and more compression means more octane or less boost but what are the advantages of doing a higher compression motor?

i do not think i will run more that 18 psi boost. 14 to 15 psi on the street and i do use my torco octain boost most the time

[Nick 1]

If you working with Rick, I'd take his advice.




Nick 1

[SMOKD U]

Call ASSC Racing here in IL. I know for a fact that they've experimented with high boost/high compression combinations in the Pro 5.0 ranks of the NMRA. I've heard some discussion coming from their program relative to increasing compression, and underdriving blowers, as a method to make more horsepower, and increase engine/component durability.

http://www.asscracing.com/

i found this on an old thread with Greg's car when he thought he had higher compression. maybe ill call them tomarrow

yes Rick is a nice guy but he likes to spin the blowers real high and i was thinking that if i ran more compression and spun the blower and motor less i could make the same Hp with less stress on parts.

[Greg@GLD]

I'm not a nice guy.
As for the compression/boost, you lower the threshold for error by running more compression. You have the PMS system right? Use the 2004 version, run the 3-bar map sensor and have Bob Kurgan tune it...

On second thought, maybe you better stick to Rick Anderson. :hehe:

[Nick 1]

I would think in a race application, more compression would be the way to go.

That might not make for a streetable combo w/o running race fuel all the time. Let us know what they say & what you plan on doing. It will be info I think a lot of people will find interesting, including myself. :D


Nick 1


I don't know the answer but I like to hear different ideas.

[Greg@GLD]

I went thru all this already myself, I'd opt for lower comp. You can tune the power into the combo and not have a meltdown-in-waiting.

But that's just my opinion...

[Nick 1]

I went thru all this already myself, I'd opt for lower comp. You can tune the power into the combo and not have a meltdown-in-waiting.

In a street car I would think this would be the way to go. (low comp)

What about a track only car ???? Like a NMRA Real Street Car ????

Any advantage of one setup over the other for Ultimate Power ?????

[Jesse James]

Just my $.02 here, one word.... "Gas". If you're planning on the car being street driven aka daily. Pump premium vs a nod to a more aggressive or race tune using race gas.

[SMOKD U]

well the car is just driven at nights and weekends. plus i always seem to have 100 + octane fuel in it.

i do not plan on going higher than 9.5 to 1 but just wondering if i should keep it at 9.2 to 1 or just jump up to 9 to 5. is there much a diff between these two little jumps.

[Greg@GLD]

Ask 10 people, get 15 answers. Been there, done that.
Rick Anderson told me not to worry as long as I had the PMS to tune with. Ron Robart (Fox Lake) told me I was crazy to consider boost on my 347 if I was above 9.5:1. Paul Svinicki (Paul's High Performance) told me my 347 was better suited to Nitrous (based on what we thought I was at versus where I am with regard to compression)
I talked to Bob Kurgan about this before he ever touched my car, he likes less compression with power in the tune. I had him tune my combo on the dyno. It's nice and safe and I get very nice MPH. With 19 degrees total advance @11PSI.

It's up to you Mark. You just popped a motor, I'd think it over. I used to say to you that I race my car more in one trip to GLD than you did in an entire summer. :D
Reliability is a nice thing to have. Rather make tons of passes with a little less power then make a few "glory passes" and go pop.

[SMOKD U]

well i understand but the pop looks like it was do to the stock crank or week block.or to much boost and timming hehe. i do want to build a motor that will last and that's why i thought more compression less boost (heated air) to the motor might be better. i understand about the 100 different answers been there done it with the last setup. in the end Rick always seemed to be right with what he told me (not to say that other people are not right either because there are also fast and they may do not agree with Rick 100 %. so the way i look at is that its my choice at the end and that can be scary

Ps back to my 70 deg garage (just got it heated thx Sam. took out the gas tank tonight and all the old pumps. also dropped the exhaust and soon drive shaft for my safety loop

PS i meant to say Rick was a nice Guy :D but you are also Greg :banana:
plus im over the Bob K. thing maybe we can meet someday and make up.

[flyin_hawaiin]

Pro 5.0 cars have intercoolers and about 50degreee IAT's.... does your blower have 50deg IAT's?

[SMOKD U]

no it does not. i do not think other than my water injection i can have any intercooler options unless i went with the vortech. and what the heck is IAT's hehe im a newbe

[flyin_hawaiin]

Inlet Air Temperatures

[SMOKD U]

i see i have a inlet temp meter and i saw the temps as high as 230 in boost. that does seem very high also. ill be adding a k probe that is more accurate this year. i wanted to see if the charge was cooler after the water/methn was injected but it does not read fast enough.

[Mark302]

Mike was running 260 for intake temps on a over spun P600 non-intercooled. Now with 22lbs he sees 200 intercooled.

[SMOKD U]

thx for the info

[SMOKD U]

i talk with the guys at asscracing today and they said not to go any higher than 9.8 to 1 and rick said 9.7 to 1. i decided to stay at 9.5 to 1 like my last motor. heres a pic of my new custom 7 inch crank pulley if i try the KB again next year. i bought it before i bought the used vortech http://www.midwestmustangassociation.com/vb3/photopost/data/500/33Picture-med.jpg

IT IS 8 RIB