been doing a little searching in the archives here in the induction forum but most people seem to post everything about their setups BUT the compression ratio haha.

I'm to the point in my ford 2.3t/volvo head hybrid build that I am ordering pistons today at lunch and I'm thinking about going with 9:1 instead of the 8.5:1 like the 2.3t normally has.

I've seen a few posts where people actually posted their C/R and it was about 9-9.5:1

what I need from you
anyone care to help me out here?? post your setup WITH compression ratio and whether your car is a daily driver or not and what kind of gas you run please.

oh and if you're wondering why I ask, its because in the end the engine I'm building will be basically a lot like a boosted H-series engine. 2.3L with a turbo and a 16v head. granted not its not related in any way but enough for me to want to look at your C/R's. thanks guys

 

ive seen 10.4:1 boosted daily and 10.6:1, a good tune will help of course... and they used 93 exxon/mobil.

why turn that boost up.

oh yeah btw what kind of car do you have a ford and a volvo.

 

oooo 10.0+ is a little bit more than what I want to work with right now but maybe in the future. hehe.

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oh yeah duh, forgot to post that

88 mustang hatch with a volvo B234F 16v head mated to a 2.3t bottom end. Same as what "would" have been the 87-88 mustang svo if ford hadn't cancelled the dohc program for it. 84-86 svo/83-88 turbocoupe/85?-89 xr4ti all had the turbo 2.3 engine in them.

I like to be different

 

The most common setups are 9.0 : 1 compression. This gives a friendly margin for making good power on pump gas. However many guys run 10:1 as well. There are pros and cons to each. Search and you will see what i mean.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by g2turbo &raquo;</TD></TR><TR><TD CLASS="quote">The most common setups are 9.0 : 1 compression. This gives a friendly margin for making good power on pump gas. However many guys run 10:1 as well. There are pros and cons to each. Search and you will see what i mean.

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10:1 boosting a 2.3T on pump gas isn't going to work. The 2.3 uses a 3.78" bore and heads that arn't overly efficient in preventing detonation, even the DOHC volvo heads. Look at a B18C1, for example, and you can see why you can get away with 10:1 compression and boost. A 3.2" bore and ultra efficient cylinder head = huge resistance to detonation. For a 2.3T I would run 8.5:1 compression or lower. You have a RWD car, you can hook up tons of horsepower on the street, why limit yourself with higher compression.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16coupe &raquo;</TD></TR><TR><TD CLASS="quote">

10:1 boosting a 2.3T on pump gas isn't going to work. The 2.3 uses a 3.78" bore and heads that arn't overly efficient in preventing detonation, even the DOHC volvo heads. Look at a B18C1, for example, and you can see why you can get away with 10:1 compression and boost. A 3.2" bore and ultra efficient cylinder head = huge resistance to detonation. For a 2.3T I would run 8.5:1 compression or lower. You have a RWD car, you can hook up tons of horsepower on the street, why limit yourself with higher compression.</TD></TR></TABLE>

good advice.

 

I personally think that 9.5:1 is a happy medium. I think 9:1 is allright but a tad low and 10:1 is just a little to much for pump gas (i know it depends on the tune)...so i just go with the happy medium 9.5:1

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SpoolnG2 &raquo;</TD></TR><TR><TD CLASS="quote">I personally think that 9.5:1 is a happy medium. I think 9:1 is allright but a tad low and 10:1 is just a little to much for pump gas (i know it depends on the tune)...so i just go with the happy medium 9.5:1</TD></TR></TABLE>

9.5:1 MIGHT be a happy medium for a honda, but not for a 2.3 ford. They came stock with around 7.8:1 compression, and you can run around 20 pounds of boost on a good sized turbo with that compression ratio. On a honda you can run that much boost with 9:1 compression. 9.5:1 on a 2.3T just doesn't make sense unless it's a full out race motor. I'm not knowledgeable to go in depth with this, but it is my understanding that a flat top piston promotes better combustion than a dished piston, so it can be advantageous in a total race application where you have lots of octane to run a flat top.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16coupe &raquo;</TD></TR><TR><TD CLASS="quote">

10:1 boosting a 2.3T on pump gas isn't going to work. The 2.3 uses a 3.78" bore and heads that arn't overly efficient in preventing detonation, even the DOHC volvo heads. Look at a B18C1, for example, and you can see why you can get away with 10:1 compression and boost. A 3.2" bore and ultra efficient cylinder head = huge resistance to detonation. For a 2.3T I would run 8.5:1 compression or lower. You have a RWD car, you can hook up tons of horsepower on the street, why limit yourself with higher compression.</TD></TR></TABLE>

For once, I agree with you. I would not run high compression on that engine. Honda's are another story though.

 

well I went ahead anyway and ordered them setup for 9.0:1 so we'll see what happens I guess

thanks anyway guys!

 

I think you'll be fine with 9:1 though.

 

9to1 compression ratio, 27psi = 606whp. 9to1 will still give you good low end,

 

I agree lower compression, and more boost. Its just safer and more reasonable for me to run more boost.

Oh ya I was at 9:1 compression with 2.0 vtec, a ractive filter and open GSR header..I out ran S4's, Zo6, supercharged lude, it was a good low 13 sec street tire car on low compression

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SOUNDEFFECTS &raquo;</TD></TR><TR><TD CLASS="quote">I agree lower compression, and more boost. Its just safer and more reasonable for me to run more boost.

Oh ya I was at 9:1 compression with 2.0 vtec, a ractive filter and open GSR header..I out ran S4's, Zo6, supercharged lude, it was a good low 13 sec street tire car on low compression </TD></TR></TABLE>

[SARCASM]No man, don't you know that as soon as you drop anything below 9.8:1 compression, your low end automatically goes to ****. You make 1/2 as much horsepower at part throttle at 9:1 compression as you do at 10:1, and with 9:1 compression you'll need to run 5 more PSI just to be even with a 10:1 motor!!!! Atleast, that's what they told me on honda tech![/SARCASM]

 

How are the combustion chambers designed?

 

they are hemispherical.

here's my head post-welding:



also, just for ***** and giggles I'll toss in a bad pic of the duramax turbo I'm going to use with the setup. Having a local turbo shop custom machine a T4 .68 turbine housing for it since the factory one is junk: