MX-3.com

onlytrueromeo wrote:If you have higher compression pistons you don't have to push as much boost which means less lag time and less loss through an intercooler. Yes you COULD just keep turning up the boost and it would be way more power than 5-7psi on a higher compression motor, or you could get 10:1 and 10-15psi and be right in the same range, not to mention having a better powerband. Why wait for 20psi when you can get the same power w/ less boost?

Compression ratio has nothing to do with lag. Engine displacement, manifold design and timing affect lag, not compression ratio.

at 10 psi i would just rock the stock pistons and maybe the millenia rods.

If you have higher compression pistons you don't have to push as much boost which means less lag time

I didn't say CR makes for less lag time, I said that boost pressure is lower, and that will affect lag time - if you can get 10psi at 3k rpms or 20psi at 4k rpms, I would call that reduced lag time because you only need to wait for 3000 instead of 4000. Less boost = less lag (psi isn't the only factor its CFM that really matters.)

Ideally when/if/hopefully when I get to turbo I will be running stock pistons on millenia S rods w/ a standalone, wideband, new injectors and a tune from someone clearly more experienced than myself. If I had more money I'd get my own pistons and rods made 9-9.5 CR), boring the engine to ~2.7L w/ titanium valves and adjustable cams so I can rev to 8k rpms happily.

onlytrueromeo wrote:

If you have higher compression pistons you don't have to push as much boost which means less lag time

I didn't say CR makes for less lag time, I said that boost pressure is lower, and that will affect lag time - if you can get 10psi at 3k rpms or 20psi at 4k rpms, I would call that reduced lag time because you only need to wait for 3000 instead of 4000. Less boost = less lag (psi isn't the only factor its CFM that really matters.)

Ideally when/if/hopefully when I get to turbo I will be running stock pistons on millenia S rods w/ a standalone, wideband, new injectors and a tune from someone clearly more experienced than myself. If I had more money I'd get my own pistons and rods made 9-9.5 CR), boring the engine to ~2.7L w/ titanium valves and adjustable cams so I can rev to 8k rpms happily.

Your way of thinking is skewed.
how is 10 psi max at 3k different from 10 psi out of a maximum of 20 at 3k make any difference?
powerband may not be the same, since you will be making more power out of 20 psi, ill trade the sizeable power difference (suiting that the turbo is up to 20 psi on a kl, over 1000 rpms anyday.)
Afterall full boost is only a gear away.

at 8 thousand rpms i wouldnt worry about titanium valves, id be more worrried about valve springs and the retainers.

^I thought I typed in springs and retainers there too...I'd get the whole kit, since ya valve themselves don't make much sense.

Well with a higher CR engine you would have more HP at 10psi than on a lower CR engine at same psi...you probably would not want to use the same turbo on a 10psi setup vs a 20psi setup, which also means reduced lag times since you could use a slightly smaller turbo. I don't think the logic is flawed because you're getting up to a similar power level at lower rpms. Yes, I know you can get more power with a higher boost application rather than with just higher CR pistons, but you lose some of the better characteristics of having an engine that makes nice power by itself - I speak plainly on a daily driver platform - lower end power for never having to downshift when making quick maneuvers (not like its hard to downshift though) having a better sounding 'engine (I hate the sound of a low CR engine at idle...most of them sound like theyre sputtering). I would never go w/ a 8-8.5:1 CR setup, because if the turbo system ever needs a revamp, you have a terrible ride. I still think 9-9.5 is the best setup, and a 10:1 ZE is a great place to start since you can make 300whp on under 10psi.

Fine, you can have your setup

case is point....

my Z at 8.5:1 @ 16psi makes 540whp.(big arse turbo's, and 740cc injectors, and DUAL 3" stainless mandrel bent exhaust, ported manifolds, stock internals.

with race gas@25-28psi is should make 700whp+


I think that there is no chance that I could run that kind of power with ANY higher compression.

true turbo people that are serious about their craft run lower compression. unless it is a race only deal.

Thanks for all the help so far guys. Although it did get a little sidetracked.
I was planning for 8.5-1 CR for him because he isn't very mechanically inclined so this engine has to have a little wiggle room, if ya know what I mean. Not to mention that the Closest tuner is 2 hours away and I don't think he has much knowledge with higher compression boosted applications.

Anybody got a t3/t4 for sale? I am on my way to the for sale section asap.

Anybody got other sites besides importperformanceparts.com for millenia rods? They have stated that they don't have any way to get them anymore.

Here, ebay, mx6.com, probetalk.com, maybe corksport. Thats your best bet, in that order for prices I feel. Corksport can be expensive.

Corksport can be expensive but they can get stuff that others can't always get. If it can be got they will get it for you.

ford 5.400 h beam rod ebay $300 2.123 jurnal and .040 bearings should fit perfect in youre crank with goo clearece in a machine

wiseco costum piston .912 pin and the compression you wish and the compression height 1.169 that would leave a .0030 deck clearence $600 for the costum pistons I personali thinck is the best way and cheapest for making a strong kl


not even 1 k invested jum seems like a nice idea dont you ?