Okay I am doing on of those f23/h22 build with eagle rods and stock block, pistons and head. I am planning on running turbo down the road. My goal hp is about 300-350 daily driver.

Here is tha catch
Will the engine work with a 7.4:1 compression ratio... I will get a chipped p28 with basemap to support the 7.4:1 compression ratio from phearable.net... I just want to know if it will work without causeing any damage to anything. I will take it to get tuned shortly after I get it running. I know the compression is way too low and will not have any power until i install the turbo.

The stock block pistions of the h22 have a negative dome of about 18cc and the eagle h beam rsx rods are about a millimeter shorter than stock accord rods and the combustion chamber is about 53.8cc and I calculated the compression to be about 7.4:1. The swept value of the block is about 563.46/76cc total combution chamber volume... that was negative dome,head gasket, negative deck hieght, and combustion chamber added together. Anyway is this too low of a compression to run everyday. I think low boost would be about 7 and hi boost would be about 17 on stock accord sleeves. I would use a small turbo that was efficient in the boosting range i described. My goal hp is around 300 after i get my turbo setup installed and tuned....

 

7.4:1 is ridiculously low, and will need a very small turbo (like the small mitusbishi turbos) to even run correctly on this. Find another piston and run 9.0:1 or above, or your off boost response and acceleration will horribly suffer no matter what you throw at it. It's not necessary just for that compression to run turbo.

 

No reason to be running 7:4:1, for a mild setup like you're looking for I'd go for 9:1 or so like Shodan said.

Heck, a lot of the race engines around here are running 10:5s.

 

yeah I was thinking of running a t25 or something that reaches effiecency at like 7 psi that would start boosting around 2500 RPM But I just wasn't sure how bad my acceleration would suffer off boost... Could anyone give me a realistic idea of how slow the motor would run off boost. My thoughts is that it would be like a stock single cam and make about 100 hp if i was lucky... I know thats extremely low but the idea in my head was that with more room in the combustion camber would allow the turbo to compress more air opposed to a smaller chamber at the same PSI. So by running lower psi making more power would be better for everyday use. This is sort of like a replacement for displacement...

So if anyone has experience in this area and has ran an engine with that low of a compression ratio could let me know .... I only time I will be under 3000RPM i won't be trying to accelerate much anyway... When I need my power I will rev sky hi...

Possibly a supercharger would better suit this build with constant boost all the time....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SovXietday &raquo;</TD></TR><TR><TD CLASS="quote">No reason to be running 7:4:1, for a mild setup like you're looking for I'd go for 9:1 or so like Shodan said. </TD></TR></TABLE>

It cant be said enough. I dont know why anyone would opt for such a low compression ratio.

 

Im not opting for a low compression ratio ... this is just the one that I am left with when putting a f23a5 bottom end with a h22 top end.... and the negative 1millimeter of deck hieght when using the je rsx pistons....

This is a link saying you want to aim for about 7:1 compression ratio when building a engine for turbo. I think the hard part would be finding a turbo that would spool real early and still boost around 17 psi I dunno if a t25 would fit those requirements... I guess i will do more research...

http://www.torquecars.com/tuning/adding-turbo.php


Modified by cdownin at 4:15 PM 5/31/2008

 

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

This is a link saying you want to aim for about 7:1 compression ratio when building a engine for turbo. I think the hard part would be finding a turbo that would spool real early and still boost around 17 psi I dunno if a t25 would fit those requirements... I guess i will do more research...
</TD></TR></TABLE>

wow, you just totally described a stock evo 9 turbo go find yourself one, iirc they go for like $300 ish???

 

Yes a evo turbo would fit those requirements,but like said earlier you wouldn't want a compression ratio that low for anything believe me.

 

A t25 on an 2.3L Honda engine is easily the worst thing you could do to that motor.

Put something bigger on. You will thank yourself later. Honda's are top end cars, if you want to make the performance of the engine something of worth you will want a turbo that actually works in the top end area.

IMO, smallest thing you should be putting on that car would be a T3/T04B.

Oh, and that link was probably written in 1995 when the "how low can you go" attitude toward compression for boost was rampant.

 

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

http://www.torquecars.com/tuning/adding-turbo.php


Modified by cdownin at 4:15 PM 5/31/2008</TD></TR></TABLE>

that link contained EXTREMELY general information, with no regard to the specifics of any application, or the fact that there are some technological/mechanical solutions to many of the anomalies that he is describing. It's not wrong information, just contains a lot of OMITTED information that is pertinent.