9:1 no question

 

Now I talked w the company building the motor he suggest highly I go 8.5:1 , they mill the head and block slightly so in reallity 8.5:1 pistons are going to be more like 9:1 compression and with 9.1:1 pistons motor will b almost at 10:1 compression. He said it's a safer route and you can just make up power loss with adding more boost.

I really don't known what to do and have to make. Decision in next 2 weeks. Don't wanna have any regrets.

 

Two things come to mind when some one pushes toward lower compression. 1 they are trying to sell what’s on the shelf or 2 they are not confident in the tune up.

Go high or go home lol. Lower is safer but just keep it stock if safety is your concern.

 

Hell yeah brother!!! MAP is shipping my 2.3 stage 2 with custom Wiseco 1400 HD 10.5:1 and I cant wait its going to be awesome I plan on using e85 exclusively but you should still be able to run pump just turn the boost down

 

so is the saying "you can make up power with more boost and timeing" kinda false?

 

not necessarily kevin knight all depends on the gas available to you to use, if your gonna be primarily on an e85/race gas diet, the a 10:1 -11:1 compression will be feasible as in you will make more power, but your more on the edge of running into knock/pre detonation. Now running race gas/e85 will cool the inlet charge there fore puttin more timing into the mix while keeping detonation at bay, but for those running primarily pump gas more specifically like in our instance in cali where were stuck with crap 91 octane, a lower compression ratio around stock 8.5:1 or 9:1 would be more feasible with runnin a bit more boost but less timing to achieve your numbers would work. So it all depends on how your goin to run your setup. If you have 93 octane in your area, im sure you can get away with a 10:1 compression, just have the tune on it a bit conservative, tuning it to MTBT, should work best for you.
Good luck

 

so should i go 8.5:1? and the motor im having built has the head and block milled and causes actuall compression to be a bit higher then the pistons rateing. i think imma go with 8.5:1 pistons and actuall compression will be like 9:1.

 

ill do a lil homework before going with the jam motor. i have seen over 5 motors that they put together, all i can say is OMG. My 3 year old daughter will do better putting those motors together.

 

10:1 call it a day

 

id say 8.5:1 or 9:1 compression would work perfectly for your setup. I dont wanna throw any stones in your pond or jinx your setup, but be careful with Jam. Have heard of some horror stories about there engines on here. Not tryin to bash them, and I know theres two sides to every story, however just be careful. Remember if somethin sounds like a great deal, theres usually a catch to it.

 

Well this is only my two cents worth but I reckon you have to look at compression ratios and cam profiles together because the combination always affects the effective cylinder pressures or the "dynamic/actual" compression ratio .

Now its your call but I wouldn't run a static (measured) CR any lower than factory std if you intend to run the factory camshafts .
Once you get into longer period/duration cams you have to raise the static compression ratio or your off boost power (torque) starts to go backwards . It does it because the trapping efficiency of longer duration cams is less at lowish revs than std cams and the dynamic/actual CR is less .
If you raise the static CR you can get the dynamic CR back up near std with slightly longer duration cams .
I do understand that people look at static compression ratios and boost pressure thinking the lower the static CR the more boost pressure they can run before chronic detonation sets in . The trouble is that you don't go everywhere on boost and if you kill your round town performance the cars a slug to drive . I think its better to have the nice round town performance and look for more power from breathing enhancements rather than stratospheric boost pressure numbers .

Its really a juggle of static CR/cam profiles/intended fuel octane/boost pressure and your overall expectations .

What are your overall goals and how many things do you intend to change ?

A .

 

English told it to me like this - if you go with a 9.1 you'll have any easier time switching to pump if you ever choose so vs going 10.5. I wen't with 9.1 on my 2.4LR because it's a little overrated.

 

Maybe if they(JAM) haven't already started the build you can have Buschur, AMS, or ER build you the engine instead. I know that Dave Buschur builds a bullet proof 2.3L longblock and he designs them to work with a relatively high static C.R. on pumpgas. ER builds a really stout 2.4L longblock and AMS has their 2.3L RR longblock.

 

Or MAP they always seem to get lost in the engine build discussion which isn't fair as they can build with the best of them for less and compared to some of the others who have already been mentioned their(MAP) customer service blows them away!!!