|Topic Review (Newest First)|
|July 14th, 2014 05:32 PM|
|Smokestang88||well I got a hold of a older post on craigslist and will be going to pickup another block hopefully this weekend that hasn't been touched yet...now I gotta try to get rid of this other thing! lol.. I wonder where I can find a good turbo head at?|
|July 13th, 2014 07:05 PM|
|OHC230||Pretty nice, thanks.|
|July 13th, 2014 05:10 PM|
Here's a link to the full build on another forum with some pictures and video.
RDY4WAR - 2007 Ford Focus ZX3
|July 13th, 2014 04:13 PM|
Not to thread jack too much, but can you give us a short rundown on your Focus?
BTW, my SVO Mustang is at 8.5:1 static, 12:1 dynamic, makes over 550 HP at the rear wheels on 91 ROM pump gas. I dealt with off boost lag by using an Eaton TVS supercharger on top of the Turbonetics T3/T4.
|July 13th, 2014 12:59 PM|
OHC, you guys aren't being offensive. I know about the poor design of the 2.3 head. This thread offers some great reading on this topic.
Compression Ratio on Turbo Engine - Yellow Bullet Forums
|July 12th, 2014 09:17 PM|
Sorry you're so far away, otherwise I could locate a lot of parts for you.
I see the number of available cars out west here, really starting to dwindle. It sucks to see so many of these things go to the crusher. A lot of those are still in decent condition. Most of the cars out here, get taken to the crusher because repair shops charge hefty sums of money for repairs and these cars won't pass a smog test. Your average shop out here wants $500-$650 for a new converter.
I went to the Pick&Pull yard today and came across at least 2 Mustangs in really nice shape, nice straight rust free bodies. They get butchered once they hit the yards. What a waste.
Speaking of wrecking yards, there is a bunch in the Michigan area. You have Ryan’s Pick a Part in Detroit; they sell engines for $175 bottom ends for $70. There not that far from you. They have a bunch of Ranger's in the yard
|July 12th, 2014 07:36 PM|
I just don't want to go out and buy another engine or travel 6 hours round trip for one... I'd like to work with the materials that I have.. 1 ported and polished head with bigger valves and shaved, spare .030" over 2.3 an block that needs a sleeve and
A full 2.3 .040" turbo motor with hypers I'll have to make something work or hope one comes availible to purchase..
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|July 12th, 2014 02:39 PM|
RDY4WAR, please don't think were beating you up, it's nice to see some visitors to our tiny forum, which is populated by people who try to make the most out of what little they have, using a dated but reliable lump of an engine. I think our responses are as honest as we can make them.
SmokeStang88 has been on this forum for a while and us regulars want to see him succeed in building a nice car. If I encourage him to use a engine combination that is prone to failure, I'd be doing him a huge disservice.
As a veteran builder of these engines, I am painfully aware of their limitations.I have performed deep analysis on this and other engine designs through the years, using a wide variety of data; empirical and computer mathematical modeling, finite element, fluid and heat analysis tools.
One look at the combustion chamber on a 2.3L should tell you where I'm coming from. Your 07 Focus has a much more efficient chamber and a much higher threshold for detonation.
SmokeStang, sorry my friend, not trying to jack your thread.
|July 12th, 2014 09:01 AM|
That is what i said right off. We are all in agreement on that. OHC was just saying that it is more safe to run higher boost with a lower cr to achieve the same hp.
That being said, one of these days i will have my 11.2:1 motor turboed at about 8-10 psi, because i want the driveability and response.
|July 11th, 2014 11:58 PM|
Originally Posted by Mikel89us View Post
Higher compression does narrow the tuning window but it makes for a much better driving street car with better off-boost power, better response, and more efficient.
For the OP, I don't think the flat top pistons are going to hurt him. He'll need to tune the car for them though considering the higher compression will raise the BSFC so the car is going to run leaner.
|July 11th, 2014 11:23 PM|
Originally Posted by RDY4WAR View Post
Horsepower is horsepower do we not agree? Well what makes horsepower? Heat energy! Heat is directly linked to HP, as in you do not get more HP without more heat. So to say that high compression is better for overall HP is to not fully understand how HP is made. Dont misunderstand and think i am calling you an idiot, please. But The increase in intake temperature is negligible since it will be made up for in the high CR motor in the compression stroke.
Remember when making HP, energy=power and heat=energy, therefore heat=power
|July 11th, 2014 09:23 PM|
I've seen this happen in person on more than one occasion. My motor for example is a 10:1 2.0L motor at 12psi with a GT28RS making 285whp. A fellow enthusiast has a 9:1 2.0L motor also at 12psi with a GT28RS and is making just 255whp. He has turned the boost up to 14psi and made 280whp but also saw IATs go up another 15*F. I've seen it on the dyno with a 8.5:1 2.3L motor with 100 octane and a GT2871R at 26psi make 396whp and the power was dying of at higher rpm from the turbo just being out of breathe. A few months later, another car with a similar build but with 9.7:1 compression made 436whp on less boost (24psi) also with 100 octane. Same dyno, similar weather. The 9.7:1 motor had about 4* less spark advance than the 8.5:1 motor, that's really it. The 9.7:1 motor also spooled about 400rpm sooner as well.
Go walk around the Outlaw drag racing crews and ask about the compression ratios of some of those turbo and supercharged engines. You'll hardly find any of them running less than 10:1 compression, especially on alcohol motors.
|July 11th, 2014 08:53 PM|
RDY4WAR, I don't really have time to discuss this at length, it is very difficult for me to find the time to visit the forums at all, but respectfully, were in disagreement on this topic, based on my education and occupation in the mechanical sciences, which I would admit, could be in error.
What you might be overlooking in your calculations are; increased oxygen densities provided by boost, which offset the thermodynamic gains from compression greatly.
If I recall correctly by a factor of 3 per PSI vs 1 point of compression at the levels were talking about.
This is assuming were are balancing against detonation. In this case, were talking about a very old engine with a dated combustion chamber design, so the
thresholds here have slim margins. I've built several 10.5 and 11.5:1 turbo 2.3 motors for customers, they are definitely down on power when compared to similar low
compression engines at safe boost limits.
Top Fuel Drag guy’s know this very well and capitalize on it by running 6.5:1 compression ratios.
Perhaps what you meant to convey, was tractable HP in relation to off boost HP and boost transition, in which case we are in total agreement.
What do ya mean the cylinder walls flexing?
A wise man once said; never be the bearer of bad news, but you know that I'm compelled to help all 2.3 Mustang guys, so I owe you the truth here.
The cylinder walls on your 2.3 are not very thick to begin with. By increasing the bore size, you're removing about 1/4 of the total wall thickness (yes they are that thin). Under boost the thinner cylinder walls are far more likely too deform/flex, which can cause a sudden catastrophic failure of the block, usually a crack will form in the cylinder wall, sometimes the whole thing goes.
That's been my experience as a 2.3L engine builder and pretty much most 2.3L engine builders will tell you the same.
N/A engines experience far lower stresses and in those applications a .040" over bore is fine.
|July 11th, 2014 03:16 PM|
|Smokestang88||its not the fact of building a .040 turbo motor... that's what I have after buying this motor and split it apart...it already has 40 overs in it but they are hypers and im not gunna risk that.. also what do ya mean the cylinder walls flexing?i haven't checked for sure but there should still be some meat in them walls...|
|July 11th, 2014 02:59 PM|
|July 11th, 2014 02:45 PM|
You would need all of the variables in order to calculate the CR, but I suspect it might be close to 9.5:-10.0:1.
In boosted engines, you're always at odds with dynamic pressure and the onset of detonation. In general, you can make more power ultimately, with a lower ratio and more boost, but as Mike indicated, also at the expense of boost response.
One of the reasons you don't see 3.820" turbo pistons, is that the cylinder walls start to flex when they are bored over .020". I personally would not build a turbo motor with a .040" over bore, unless I were using one of the Racing SVO blocks.
Honestly, you'd be better off to find an un-bored junkyard block and having it machined.
|July 11th, 2014 02:02 PM|
|vristang||What would the static cr be?|
|July 10th, 2014 08:36 PM|
|Mikel89us||The higher compression will help out with turbo spool up, and throttle response. As well as fuel mileage. With the stock turbo and ecu, you will see a bit of a power gain, and you will need to make sure your fuel system is up for the task. Mostly the injectors, the 35# stock ones might be up to the task, but I would guess it would be wise to up to some closer to 40#|
|July 10th, 2014 08:25 PM|
Flat top forges in a turbo motor?
Trying to find forged pistons that are 40 over for my turbo motor I bought.. Only ones I can find without spending 600 bucks for a set are flat tops. I know it will Bump up compression alittle but would they be alright to run in a combo of a stock head and turbo block with possibly a LA3 ecu?
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