Planning Ahead: Boosting at 13.5:1
#1
Honda-Tech Member
Thread Starter
Join Date: Aug 2007
Location: Chicaaaaaaaaago
Posts: 431
Likes: 0
Received 0 Likes
on
0 Posts
Planning Ahead: Boosting at 13.5:1
What's happening guys? I'm gonna start off by stating that this is a very long term build, with at least 2 years between now and completion.
This plan of my started with a bit of horrible luck, and a great deal on a set of forged 89mm 13.5:1 JEs.
The motor is a 94 h22a that decided to play patty-cake with a brand new set of DH-Racing "dome-top" valves. Go ahead and use this moment to make fun of me lol. I know it was a bad decision, and I've since accepted that and moved on. ANYWHO...
Money isn't really going to be an object, as it is impossible to take on this kind of adventure without some deep pockets.
I realize that with such a high CR, you're pretty much asking for trouble when you add boost to the mix. But hey, you only live once right?
With that said, my plan is to keep things as safe as possible, as I do not want to waste $3k or more in block building on something that could have been easily avoided.
Just wanted to see what everyone's thoughts on such a build might be. The highest CR I've seen on a boosted setup on H-T thus far, has been somewhere in the 11.5:1 area. Anything is possible with enough tuning and precaution, or so I've been lead to believe. Criticism is and will always be very welcomed. Let me know what you guys think. Thanks!
Also, if anyone is interested, I have plenty of pictures of the gnarly block carnage.
This plan of my started with a bit of horrible luck, and a great deal on a set of forged 89mm 13.5:1 JEs.
The motor is a 94 h22a that decided to play patty-cake with a brand new set of DH-Racing "dome-top" valves. Go ahead and use this moment to make fun of me lol. I know it was a bad decision, and I've since accepted that and moved on. ANYWHO...
Money isn't really going to be an object, as it is impossible to take on this kind of adventure without some deep pockets.
I realize that with such a high CR, you're pretty much asking for trouble when you add boost to the mix. But hey, you only live once right?
With that said, my plan is to keep things as safe as possible, as I do not want to waste $3k or more in block building on something that could have been easily avoided.
Just wanted to see what everyone's thoughts on such a build might be. The highest CR I've seen on a boosted setup on H-T thus far, has been somewhere in the 11.5:1 area. Anything is possible with enough tuning and precaution, or so I've been lead to believe. Criticism is and will always be very welcomed. Let me know what you guys think. Thanks!
Also, if anyone is interested, I have plenty of pictures of the gnarly block carnage.
#2
Honda-Tech Member
Join Date: Mar 2001
Location: Phoenix, AZ, USA
Posts: 2,708
Likes: 0
Received 0 Likes
on
0 Posts
Re: Planning Ahead: Boosting at 13.5:1
How much power are you looking to make, and what fuel do you plan on using?
If all else fails, you could always buy a new set of pistons.
If all else fails, you could always buy a new set of pistons.
#4
Honda-Tech Member
Thread Starter
Join Date: Aug 2007
Location: Chicaaaaaaaaago
Posts: 431
Likes: 0
Received 0 Likes
on
0 Posts
Re: Planning Ahead: Boosting at 13.5:1
Realistically, I'd like to be at or around 500whp. If the block and all permits, I'd definitely like to see 700whp. But once again, I'm shooting for a more realistic 500whp as of now.
I can't explain how great it would be to have some experience chime in here. More the merrier. I will refrain from bothering people via PM this early in the game though. It's still a pipe dream right now. I have the car (still needs custom axles, and mounts), the block (unbuilt and needing head), the tranny (needs LSD), pistons, and a few other odds and ends right now.
This motor will be going into an '89 Prelude just in case anyone was interested or curious.
#5
Honda-Tech Member
Join Date: Jan 2004
Location: Mid atlantic
Posts: 3,629
Likes: 0
Received 0 Likes
on
0 Posts
Re: Planning Ahead: Boosting at 13.5:1
bump for an intersting build. Im currently running a 10:6.1 GSR setup and I LOVE the power out of boost, not sluggish at all like some 9:0.1 setups or less. 13 is high thought, definately get yourself a tuning appointment with someone who has experience with these type of setups, evans, tony, ect ect, that will be your best investment. Also, i doubt this car will be able to run on anything less than 110. maybe look into an e85 setup at worst, but she will certiantly not like 93 pump. anyway, good luck my friend.
#6
Honda-Tech Member
iTrader: (5)
Join Date: Dec 2005
Location: RENO, NV
Posts: 1,934
Likes: 0
Received 0 Likes
on
0 Posts
Re: Planning Ahead: Boosting at 13.5:1
Damn, thats high compression. Thought about all motor?
definately race gas only motor... you should send that head off to port flow and let them do it up, with some nice cams and valvetrain and a tune that thing should be gnarley!
definately race gas only motor... you should send that head off to port flow and let them do it up, with some nice cams and valvetrain and a tune that thing should be gnarley!
#7
Honda-Tech Member
Thread Starter
Join Date: Aug 2007
Location: Chicaaaaaaaaago
Posts: 431
Likes: 0
Received 0 Likes
on
0 Posts
Re: Planning Ahead: Boosting at 13.5:1
Sorry I totally neglected the fuel question!
Yeah race gas might be the only option, or maybe lowering the f--- outta the CR via a stack oh head gaskets lol.
I'm not against E85 at all. I've heard some good things about it, at least for N/A builds anyway.
Yeah race gas might be the only option, or maybe lowering the f--- outta the CR via a stack oh head gaskets lol.
I'm not against E85 at all. I've heard some good things about it, at least for N/A builds anyway.
Trending Topics
#9
Honda-Tech Member
Re: Planning Ahead: Boosting at 13.5:1
this would be a great motor to run on alternative fuel...look into e85 (or straight ethanol)...methanol...alcohol....etc
#10
Honda-Tech Member
Join Date: Nov 2002
Location: Houston, TX, USA
Posts: 676
Likes: 0
Received 0 Likes
on
0 Posts
Re: Planning Ahead: Boosting at 13.5:1
Its totally doable with the right fuel/setup .. The better the whole setup the lower octane fuel you'll be able to get away with theoretically, but I don't see this happening on pump gas. You could probably make decent power with e85 before reaching the limits of the fuel but I don't think you'll reach 500.. Not saying its not possible, but its not very likely.. Now if you put it on Q16 then should be no problems making your desired power level. Go BIG on turbo exhaust housing, 4in outlet, T4, 1.20 A/R.. Spool won't be too much of an issue with that level of compression.
Good luck and let us know how it goes..
Good luck and let us know how it goes..
#11
Re: Planning Ahead: Boosting at 13.5:1
Check out this Evanstuning dyno test where the only change was compression ratio. It's interesting, almost nothing was gained in spoolup but power was higher once full boost was acheived. The most interesting part to me is how much more timing the engine wanted to make MBT.
http://forums.evans-tuning.com/viewt...hp?f=15&t=1612
http://forums.evans-tuning.com/viewt...hp?f=15&t=1612
#12
Honda-Tech Member
Thread Starter
Join Date: Aug 2007
Location: Chicaaaaaaaaago
Posts: 431
Likes: 0
Received 0 Likes
on
0 Posts
Re: Planning Ahead: Boosting at 13.5:1
Its totally doable with the right fuel/setup .. The better the whole setup the lower octane fuel you'll be able to get away with theoretically, but I don't see this happening on pump gas. You could probably make decent power with e85 before reaching the limits of the fuel but I don't think you'll reach 500.. Not saying its not possible, but its not very likely.. Now if you put it on Q16 then should be no problems making your desired power level. Go BIG on turbo exhaust housing, 4in outlet, T4, 1.20 A/R.. Spool won't be too much of an issue with that level of compression.
Good luck and let us know how it goes..
Good luck and let us know how it goes..
Check out this Evanstuning dyno test where the only change was compression ratio. It's interesting, almost nothing was gained in spoolup but power was higher once full boost was acheived. The most interesting part to me is how much more timing the engine wanted to make MBT.
http://forums.evans-tuning.com/viewt...hp?f=15&t=1612
http://forums.evans-tuning.com/viewt...hp?f=15&t=1612
One poster in that thread had a good point though; the small size of the turbo allows it spool quickly enough to negate the small bump in compression. Maybe?
#13
Honda-Tech Member
Join Date: Jan 2004
Location: Mid atlantic
Posts: 3,629
Likes: 0
Received 0 Likes
on
0 Posts
Re: Planning Ahead: Boosting at 13.5:1
I definitely agree on going big with the turbo. My idea was that the high CR would allow the car to have the initial response like an N/A beast, which would easily carry it into boost. Once you're in boost all hell should break loose. That's my theory anyway...
That is pretty interesting. I'm kinda shocked that going from 9:1 to 10:1 only yielded 15whp, which almost makes it not worth the risk.
One poster in that thread had a good point though; the small size of the turbo allows it spool quickly enough to negate the small bump in compression. Maybe?
That is pretty interesting. I'm kinda shocked that going from 9:1 to 10:1 only yielded 15whp, which almost makes it not worth the risk.
One poster in that thread had a good point though; the small size of the turbo allows it spool quickly enough to negate the small bump in compression. Maybe?
Your right about the small turbo offsetting the change in power a bit, not going to take much to spool that reguardless of the compression. But if you read on evans explains that the change in compression does not correlate linearly with the power. So by simply increasing the compression you are not increasing the power at the same rate. As a result it makes more sense to run a lower compression motor and let the turbo get you to your desired power goals.
#14
Honda-Tech Member
Join Date: Nov 2002
Location: Houston, TX, USA
Posts: 676
Likes: 0
Received 0 Likes
on
0 Posts
Re: Planning Ahead: Boosting at 13.5:1
First of all, having a lower compression will almost always require more timing to reach MBT as the mixture is less dense therefore the flamefront speed will be lower, also .020 larger bore will also require a bit more timing to reach MBT cause the flamefront has a greater distance to travel... Yes only a small difference but good for a degree or 2.
Also The difference in compression I DO believe will have much less of an effect in this senerio due to the restrictive nature of the setup. In a less restrictive stup I think having a higher static CR will make a larger difference.. There is that point where gains from compression will start to fall off though. So if your fuel can support it, and your setup can support it, I think higher CR is the way to go on a RACE motor. Some motor/chamber designs just don't tolerate the higher static CRs so in those cases your better off with less compression so you can get more air and fuel in (forced) before knocking. While higher CR does make more power, theres a point at which gains from compression become outweighed by being able to stuff more boost in the cylinder safely. For the bestest most maxest power senerio there a perfect balance of boost and static CR that would probably take forever to figure out and only be valid for THAT specfic setup.
Also The difference in compression I DO believe will have much less of an effect in this senerio due to the restrictive nature of the setup. In a less restrictive stup I think having a higher static CR will make a larger difference.. There is that point where gains from compression will start to fall off though. So if your fuel can support it, and your setup can support it, I think higher CR is the way to go on a RACE motor. Some motor/chamber designs just don't tolerate the higher static CRs so in those cases your better off with less compression so you can get more air and fuel in (forced) before knocking. While higher CR does make more power, theres a point at which gains from compression become outweighed by being able to stuff more boost in the cylinder safely. For the bestest most maxest power senerio there a perfect balance of boost and static CR that would probably take forever to figure out and only be valid for THAT specfic setup.
#15
Honda-Tech Member
Join Date: Jan 2004
Location: Mid atlantic
Posts: 3,629
Likes: 0
Received 0 Likes
on
0 Posts
Re: Planning Ahead: Boosting at 13.5:1
First of all, having a lower compression will almost always require more timing to reach MBT as the mixture is less dense therefore the flamefront speed will be lower, also .020 larger bore will also require a bit more timing to reach MBT cause the flamefront has a greater distance to travel... Yes only a small difference but good for a degree or 2.
Also The difference in compression I DO believe will have much less of an effect in this senerio due to the restrictive nature of the setup. In a less restrictive stup I think having a higher static CR will make a larger difference.. There is that point where gains from compression will start to fall off though. So if your fuel can support it, and your setup can support it, I think higher CR is the way to go on a RACE motor. Some motor/chamber designs just don't tolerate the higher static CRs so in those cases your better off with less compression so you can get more air and fuel in (forced) before knocking. While higher CR does make more power, theres a point at which gains from compression become outweighed by being able to stuff more boost in the cylinder safely. For the bestest most maxest power senerio there a perfect balance of boost and static CR that would probably take forever to figure out and only be valid for THAT specfic setup.
Also The difference in compression I DO believe will have much less of an effect in this senerio due to the restrictive nature of the setup. In a less restrictive stup I think having a higher static CR will make a larger difference.. There is that point where gains from compression will start to fall off though. So if your fuel can support it, and your setup can support it, I think higher CR is the way to go on a RACE motor. Some motor/chamber designs just don't tolerate the higher static CRs so in those cases your better off with less compression so you can get more air and fuel in (forced) before knocking. While higher CR does make more power, theres a point at which gains from compression become outweighed by being able to stuff more boost in the cylinder safely. For the bestest most maxest power senerio there a perfect balance of boost and static CR that would probably take forever to figure out and only be valid for THAT specfic setup.
#16
Honda-Tech Member
Thread Starter
Join Date: Aug 2007
Location: Chicaaaaaaaaago
Posts: 431
Likes: 0
Received 0 Likes
on
0 Posts
Re: Planning Ahead: Boosting at 13.5:1
Just quoting a post Turbo-Charged made in a thread...
With that said, it looks like good numbers on 13:1ish CR is fully possible. He doesn't mention fuel, so that's anyone's guess on what it's running.
But the key to what he said is less boost (and assuming less fuel), which as we all know is a good thing.
it crept to 18, it attempted to hold 14. fwiw with a .63 t3 35r my own personal car made 550@18psi as well. whats different here is this car has a 95mm stroker crank, and my car was 13:1 compression....hence making more power with less boost.
i totally agree these numbers are high compared to your typical 35r set up, i have tuned tons of them. seems 15-18psi usually gets you in the mid/high 400's.
truthfully i think the crank, the rods, the pistons, and the sleeves do not belong in a motor making this kind of power. lol
i totally agree these numbers are high compared to your typical 35r set up, i have tuned tons of them. seems 15-18psi usually gets you in the mid/high 400's.
truthfully i think the crank, the rods, the pistons, and the sleeves do not belong in a motor making this kind of power. lol
But the key to what he said is less boost (and assuming less fuel), which as we all know is a good thing.
#18
Re: Planning Ahead: Boosting at 13.5:1
I have never had the chance to tune a car with only the bore size changed. You really need a degree or two for half a mm overbore? Seems like that's a lot of timing change for a flame front that only has to travel a quarter mm extra in each direction. Is the travel speed very non-linear at the end of the burn or something. I assume you're talking about gasoline.
Thread
Thread Starter
Forum
Replies
Last Post