Thoughts on a higher CR motor with low boost?

[HiSPL]

I'm running an NA skinny rod motor on LH 2.2. Currently planning/working on all the typical NA mods. 2.5" exhaust, shaved head, A cam, Efan, lightened flywheel.

Basically it's a street car and my daily communter. I just want it to be more playful, not worried about all out power.

My question, which is purely theoritical at this point, is this:

If a +T kit fell into my hands, I might be tempted to buy it. However this would likely come after I've increased my static CR and running an NA cam, etc. The cam is easy enough to swap out for a T cam, but what about the static CR? Would LH2.2 handle running a High CR/lo boost setup? By low boost I'm thinking 5-8 pounds. Stockish levels.

What are your thoughts? Would it only be possible with a standalone? Will I blow things up? Will I become destitute? Will Bullwinkle ever get that bowl of cereal?

[HiSPL]

Also I should say I want to run pump gas. It's my daily. Don't have any e85 pumps on my route.

[dl242gt]

I would keep the CR where it is if you plan on even light boost. With even higher compression you'll be that much more closer to detonation and it may be hard to manage that with higher compression than a stock B230F.

The Light Pressure Turbo setup was used by Volvo with the white blocks and if I recall correctly they used 9.2 CR so a stock B230F is already in the good zone for LPT engine. With the small turbo and high compression it'll probably be instant spool.

[shoestring]

If the cam you're currently using has longer duration than the T (it's hard to imagine it doesn't), I would keep it to reduce the dynamic compression ratio and therefore detonation sensitivity.

[Dirty Rick]

Boost It!
till the rods fold up!

A cam with no overlap is best for boost.

[culberro]

I'd pull the head and open up the combustion chambers on the exhaust side. Drop the CR a bit and improve flow... win-win.

[HiSPL]

Originally Posted by shoestring

If the cam you're currently using has longer duration than the T (it's hard to imagine it doesn't), I would keep it to reduce the dynamic compression ratio and therefore detonation sensitivity.

I currently have an M cam. Will be using an A probably as an NA cam. If I did a +T I'd swap to a ipd T cam or similar.

[HiSPL]

Originally Posted by culberro

I'd pull the head and open up the combustion chambers on the exhaust side. Drop the CR a bit and improve flow... win-win.

Not out of the question. I'd like to get a head from teh junkyard to do all the butchery on then just swap it. So some porting and clean up could be done for sure.

[esmth]

I think stock ez117k will be the biggest issue. I think you may need to have less timing in the high load to WOT parts of the map but it's been a little bit since i've messed around with turbo setup. Could always turn the distributor down to reduce detonation at WOT but then you will suffer from a poorer idle and less cruise efficiency which is not ideal for a daily. Or find someone that can make you a chip.

Here is stock 012 EZK map for reference:

[HiSPL]

Originally Posted by esmth

I think stock ez117k will be the biggest issue. I think you may need to have less timing in the high load to WOT parts of the map but it's been a little bit since i've messed around with turbo setup. Could always turn the distributor down to reduce detonation at WOT but then you will suffer from a poorer idle and less cruise efficiency which is not ideal for a daily. Or find someone that can make you a chip.

Here is stock 012 EZK map for reference:

I guess it would mean full standalone time if that's the case. I'm not sure I'd want to invest anything in trying to make the chrysler ignition work better. I'd rather spend that money on something that works, and also have to find more fuel at the same time.

Makes sense to get a speeduino or microsquirt.

[dl242gt]

Yeah, build yourself a light pressure turbosquirt. The head work was one of the nicest changes to my turbo. Made the engine run more smooth at all rpms and has power improved everywhere. For a fun street car. Don't change the valve size.

[HiSPL]

Originally Posted by dl242gt

Yeah, build yourself a light pressure turbosquirt. The head work was one of the nicest changes to my turbo. Made the engine run more smooth at all rpms and has power improved everywhere. For a fun street car. Don't change the valve size.

Right on.

One of the hardest things is leaving it "good enough" and resisting the urge to mortgage teh farm on some monster motor that you'll never enjoy!

[dl242gt]

LOL the scope creep is real. I had my machine shop do the valve unshrouding, then bowl, and port work on my head. New fresh 3 angle valve job. New stock turbo exhaust valves and left it at that. That is all in a 405 head from a Canadian B23E. I usually just run about 12psi and it's fun even at that low level.