Turbo Stroker DD going for economy

[duck454ss]

Still minimal progress on the engine build. I've been a victim of the down turn in the Canadian oil and gas industry and its been a bit of a struggle. BUT that hasn't stopped the build, just told the engine shop to slowly chip away at the build when they have time.


So I've been doing some thinking/shopping. Mainly looking at gauges at the moment. Given i'm running the blower there are a few gauges the stock cluster doesn't have. So i have a few questions/ideas about the gauges to run.

A/F ratio:Innovative Motorsports dual gauge https://www.summitracing.com/int/parts/inn-3891
Boost/vac: Anticipated max boost is 10psi i'm looking for a boost/vac gauge with 15-20psi max (Autometer has a bunch... suggestions? is it worth having vac?)
EGT: is it worth while running an individual pyro per 3cyl bank? what is a max temp a person should expect?


feedback and suggestions are welcome

Cheers

[duck454ss]

I’m getting close to finishing the engine on my build and I need to determine final CR. Head vol is about 60cc and with the 31cc pistons my CR can vary. For a boosted application and the edelbrock aluminum head what sort of DCR should I be aiming for?

Boost can be as high as 10psi. Using a cometic head gasket I can have a DCR at 10psi from 11.2 to 13.0 depending on thickness of the gasket (0.030 – 0.120). Does the gasket thickness/quench/DCR play a big part in combustion chamber performance? Quench numbers can be 0.0285 – 0.1185 since my pistons are 0.015 above deck height.

Having a low DCR helps with not having the need for premium fuel but I don’t want to outright sacrifice combustion performance. Simply put I don’t want to sacrifice performance but I also want the engine to be reliable and not need “special treatment”.

Thoughts?

[SkylinesSuck]

PSI numbers are almost pointless. CFM of the turbo and where you are in it's efficiency range are what matter. It's cylinder pressure (and temp) really (which are affected by boost pressure, yes).

10 psi on a little dinky turbo ≠ 10 psi on a GT45R big boy turbo.

[SkylinesSuck]

Same thing goes for superchargers.

[duck454ss]

PSI numbers are almost pointless. CFM of the turbo and where you are in it's efficiency range are what matter. It's cylinder pressure (and temp) really (which are affected by boost pressure, yes).

10 psi on a little dinky turbo ≠ 10 psi on a GT45R big boy turbo.

not to be argumentative but psi boost/cylinder pressure is all that matters in my situation. CFM and efficiency of the turbo or supercharger are a separate topic that has already been addressed earlier in the thread.

What i was looking to address is what is an acceptable DCR in my application assuming i don't have intake temp issues.

Just to add some tech to this post I've determined that i will be running a 0.051 head gasket giving me ~8.5 SCR/7.4DCR. DCR will be around 12:1 under full boost without over spinning the supercharger (10,000 rpm) and making it a heat pump. To combat elevated intake temp i'll be using water methanol..... with all this being said this will be a daily driver so the above is worst case (most abusive) scenario.

During normal driving conditions i should only see my DCR creep up to 10-11:1 and with 7 psi boost. Water meth will be "triggered" at around 4-5psi boost to make sure there aren't any heat issues.

[SkylinesSuck]

Busy so quick post, but I was saying cylinder pressure (and temp) is everything, and psi of boost doesn't matter. Half of what you said.

[duck454ss]

Well right when i thought i had everything lined up i think i caught a snag...... injector selection...

what injectors can i use in a 2005 wrangler? i thought i could use early 90's mustang injectors but somewhere somehow i am being lead to doubt myself.

apparently the 05-06 wranglers use 60psi fule pressure.... that kind of messes up my injector flow..


HELP

[Cummins90]

Find the spec by searching the injector part number. Injectors are rated at 3 bar. I am running 36lbs ev1 style on my 96 with an m90 at 10psig. Injectors are scaled using an AEM FIC.

[duck454ss]

i think i narrowed down an issue with why the engine is running like crap. i'm suspecting that the timing chain might have been installed incorrectly and the cam is advanced way too far forward.

intake center line is 107
Lobe Sep:113
Intake duration: 254
Exhaust duration: 262

if by some chance the timing chain is off by a tooth (or 2) and/or the rollmaster timing chain is advanced at all it would explain the shitty sound.

question.... how far advanced can this cam be before things run like crap? thoughts?

[duck454ss]

fun story..... engine was running horrible and making a sound that was similar to that of a cummins 12 valve. dropped the pan to see what was going on to find that the piston in cyl 1 could be moved by hand......


engine is pulled and back at the machine shop.... yay.

[SkylinesSuck]

Do you know why?

[duck454ss]

Somehow cylinder 1 washed out and piston is collapsed. Engine builder claims its mass over fueling but we never saw codes related to that cylinder. fighting with engine builder and mechanic who installed it to see where it all went wrong.... fun blame game.

less than 30 min of run time on the engine.

[SkylinesSuck]

That sucks man. Sorry to hear it.

[duck454ss]

Fun little update....

Since we cant pin point exactly where it all went wrong; and during break in questions were raised about how the engine sounded... the engine is being rebuilt.

no one is willing to accept full responsibility so i'm on the hook for parts... yay

silver lining is that the first version of this engine was a dog N/A with 9:1 compression. so now i'm going to bump that up to compensate during my break in phase (couple years as daily driver). then when i put the blower on i'll use about half the boost.

deviation from original design

Bore: was 3.905 now 3.935
Piston dish: was 31cc now 17cc
SCR: was 9:1 now 10.90
DCR @ full boost (6psi) ~5500 rpm = 12.3

once boost reaches 3.5psi or WOT i'll be injecting water meth.......

thoughts?