As I read through the different combinations,I realized some of the DCR numbers would be over 8.5. I thought those numbers were supposed to be closer to 8:1. Please educate me.
What fuel? Iron or aluminum heads? Despite the religious adherence of some to a specific number, many motors have been built and successfully run that are outside the dcr sweet spot.
Some had iron and some had aluminum. I'm just trying to get some knowledge. There is a thread on here titled 10 second combinations. I think it is amazing how many different combinations are listed. 308s cam seems popular.
Exactly^ lots of ways to skin a cat. Personally, if I were building a pump gas combination I would try to maximize the squish band by zero decking the dished pistons, use a .040" gasket, and try to keep below 10.25:1 for iron and 10.6:1 for aluminum, and run a cam that put me around 7.5:1 dynamic compression for either. My philosophy (take it or leave it) is that you don't gain a lot by pushing the dcr up and running a smaller cam; only open up the possibility for detonation by running on the ragged edge, so why do it? There is probably a lot more horsepower to be found in optimizing the overlap and duration numbers to the RPM you want to run in, and then chassis and converter are the other essential piece to get it to ET. If you're racing, why build a pump gas combination anyway? E-85 or race fuel is a much safer bet, and then you have the option of going 12.5:1 to make some real power.
I’ve been considering E-85. There’s a station within a mile of my house. I have 3 carbs. 2 Holley (800&850)and a 1000 cfm Race Demon. All are mechanical secondary. I don’t know who to send one to so it could be converted. I read an article by Mark Sullens and he said no one needs more than 850 cfm on E-85
Eric at Horsepower innovations is my suggestion I went 10.80s first time out with the following Wiescos sitting .052 deep with a .041 gasket and 65cc heads,...with a 259/267 615 615 110lsa solid
I'll never see 10's. I'm more interested in the idea of running 8.5 DCR or more and making it work. I've seen my dad and brother scrounge through parts,throw them together and run damn well. I have a small cam and about 10:1. My DCR is 7.4-7.5. I like how it runs. If I could figure a way to get closer to 8:1,I'd like to see how much difference it makes. A set of Stage 1 SE heads out of the box and I'd be there. My flow numbers would be up 40 on both sides,but do I want to spend 3k to find out if it's worth it? I got $1200 in my iron heads. I'll probably only get half that if I can sell them. Only time will tell. I do appreciate the comments and I'm really just trying to understand how it all works.
What gaskets you running? But you wouldn't see any real improvement imo,..like my combo above it was far from optimal but it didn't care about its lack of quench and whatnot,..ran hard on pump 93
Cometic .030, zero deck,73 cc head,24cc dish,TA113 cam. Butt dyno says it pulls a lot harder than the warmed over SBC it replaced. SBC ran low 8's in the 1/8th.
Most ppl honestly with 10 second motors are not too overly worried about dcr. They are willing to cut the fuel needed to keep the motor happy
I figured fuel quality had a lot to do with it. I don’t have a lot of experience with engines above 10.5:1. I mainly keep to the street but would like to visit the strip more often. My kids are grown and I need something new to keep me broke and frustrated.
"I need something new to keep me broke and frustrated." lol...... this hobby or sickness WILL make you go broke and you will invent some new bad words!
