Turbo set up for F20B DOHC?
11-02-2014, 08:22 AM
#1
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Turbo set up for F20B DOHC?
Hey I'm wondering if anyone has a suggestions for my build
https://honda-tech.com/honda-accord-...-help-3225176/
Going to be getting a F20B DOHC vtec engine from japan and switch out the pistons with low compression pistons from a F22A engine because the compression is too high for a significant amount of boost+reliability. Compression will be about 8:1 instead of 11:0.
Anyone have a suggestion for a good turbo that won't get too hot and push 8-15 pounds of boost. I am on a budget for the build though.
https://honda-tech.com/honda-accord-...-help-3225176/
Going to be getting a F20B DOHC vtec engine from japan and switch out the pistons with low compression pistons from a F22A engine because the compression is too high for a significant amount of boost+reliability. Compression will be about 8:1 instead of 11:0.
Anyone have a suggestion for a good turbo that won't get too hot and push 8-15 pounds of boost. I am on a budget for the build though.
11-02-2014, 09:26 AM
#2
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Re: Turbo set up for F20B DOHC?
11:1 is great for turbo. Leave the stock pistons.
8:1 would suck.
Also "8-15 pounds of boost" means nothing. How much power do you want to make?
Go read the Forced Induction FAQs. All of them.
8:1 would suck.
Also "8-15 pounds of boost" means nothing. How much power do you want to make?
Go read the Forced Induction FAQs. All of them.
11-02-2014, 09:31 AM
#3
Re: Turbo set up for F20B DOHC?
Back in the 90s, when the best thing we had access to was stupid VAFCs and FMU hacks, low detonation thresholds were important - there was no fine tuning, so keeping the engine from detonating was very important. That is the ENTIRE purpose of lowing compression.
Today, we live in the age of this great thing called technology. There are plenty of engine management options that offer real-time logging, and fine tuning down to the hair, so you don't need low compression. in fact, you can RAISE compression, slap a turbo on there, and still make amazing power, especially with forged internals. The norm nowadays (at least, for people who aren't stuck in the 90's), is 10.5:1 or more. You still get the same final power, but you get a MUCH better powerband, because you actually have power outside of boost. When you lower your compression ratio, you lose power. Period. If you want a car that isn't a gutless piece of trash, that means you have to run a smaller turbo, so that a quicker spool can make up for the lack of power. A smaller turbo means a lower top-end. With the higher compression ratios allowed by better engine management options (and better fuel, too), you can get more power outside of boost, which means you can run a larger turbo that would kick in a little later, which means you can get more power in boost, too.
You're welcome.
Today, we live in the age of this great thing called technology. There are plenty of engine management options that offer real-time logging, and fine tuning down to the hair, so you don't need low compression. in fact, you can RAISE compression, slap a turbo on there, and still make amazing power, especially with forged internals. The norm nowadays (at least, for people who aren't stuck in the 90's), is 10.5:1 or more. You still get the same final power, but you get a MUCH better powerband, because you actually have power outside of boost. When you lower your compression ratio, you lose power. Period. If you want a car that isn't a gutless piece of trash, that means you have to run a smaller turbo, so that a quicker spool can make up for the lack of power. A smaller turbo means a lower top-end. With the higher compression ratios allowed by better engine management options (and better fuel, too), you can get more power outside of boost, which means you can run a larger turbo that would kick in a little later, which means you can get more power in boost, too.
You're welcome.
11-03-2014, 06:40 AM
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Re: Turbo set up for F20B DOHC?
The issue with keeping the pistons and the high compression is I'll lose the reliability of the engine since the ringlands tend to break because of the higher compression in that specific engine. This is my daily driver since it's the getting colder and I can't ride my motorcycle. So I can't just have the ringlands fail randomly because then I would be out a car. If one of you guys has a solution to stopping the ringlands from breaking then let me know. I only intend on turning up the boost for track days so 8-12 should be fine for me.
11-03-2014, 07:05 AM
#6
That logic doesnt work.
Ringland breaks because of torque. If you produce 300wtq on low comp, and 300wtq at high comp, the ringlands will be under the exact same load, but the high comp engine will be a MUCH more fun car to drive.
Psi is irrelevant. How much hp do you want?
Ringland breaks because of torque. If you produce 300wtq on low comp, and 300wtq at high comp, the ringlands will be under the exact same load, but the high comp engine will be a MUCH more fun car to drive.
Psi is irrelevant. How much hp do you want?
11-03-2014, 08:10 PM
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Re: Turbo set up for F20B DOHC?
This is from the CB7 forums that I was reading about the f20B DOHC motor which is where I got my information on the ringlands. I'm looking at getting around the same numbers (327 Hp and 240 ft pounds of torque.) But the engine has to last me at least through college which I start next fall. So 4-5 years with driving it hard but not red lining it all the time of course.
and
hey guys just recently finished up my boosted F20B dohc vtec 100% bone stock. stock head, stock headstuds, stock rods, stock pistons. etc....
i finished it up the end of this past winter. (2012) and april 14th 2012 i went to innovative motorworks in carlisle, PA to get tuned. and i was more than happy with the results. i did not expect it to go as well as it did.
final numbers were 327whp 240lb ft.... this was on wastegate pressure at 7psi. on a bullseye power 57trim with a .70ar exhaust housing. and full 3" exhaust.
parts used to reach this power goal.
bullseye power 57trim with upgraded .70ar exhaust housing
injector dynamics 1000cc injectors
go autoworks Large front mount intercooler kit
BRMS h22 twisted ram manifold
turbosmart 38mm wastegate 7psi spring
full 3" straight pipe exhaust.
there are lots more but these are the essentials to a healthy and efficient turbo setup. im thinking of putting cp pistons on my spare set of f20B rods and putting head studs in and going for 400. i will upload pics of the car and dyno plots as well
i finished it up the end of this past winter. (2012) and april 14th 2012 i went to innovative motorworks in carlisle, PA to get tuned. and i was more than happy with the results. i did not expect it to go as well as it did.
final numbers were 327whp 240lb ft.... this was on wastegate pressure at 7psi. on a bullseye power 57trim with a .70ar exhaust housing. and full 3" exhaust.
parts used to reach this power goal.
bullseye power 57trim with upgraded .70ar exhaust housing
injector dynamics 1000cc injectors
go autoworks Large front mount intercooler kit
BRMS h22 twisted ram manifold
turbosmart 38mm wastegate 7psi spring
full 3" straight pipe exhaust.
there are lots more but these are the essentials to a healthy and efficient turbo setup. im thinking of putting cp pistons on my spare set of f20B rods and putting head studs in and going for 400. i will upload pics of the car and dyno plots as well
You should plan on forged internals sooner than later. The stock ringlands won't hold for long, and they could do damage to the sleeves when they break.
Very nice numbers, though!
Very nice numbers, though!
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11-03-2014, 09:48 PM
#8
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Re: Turbo set up for F20B DOHC?
Sounds like a horrible idea to literally depend on a boosted honda for reliable transportation.... for any period of time, especially 5 years, and even more so if you're going to drive it hard like you say.
You need a second car.
You need a second car.
11-04-2014, 03:26 AM
#10
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Re: Turbo set up for F20B DOHC?
F20b from JDM importer - $600
Pistons, rings, gaskets, machine work, etc - $1k+, + cost of longblock
You would be better off leaving it stock and just replacing the entire motor after the ring lands go...
Pistons, rings, gaskets, machine work, etc - $1k+, + cost of longblock
You would be better off leaving it stock and just replacing the entire motor after the ring lands go...
11-05-2014, 10:16 AM
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Re: Turbo set up for F20B DOHC?
Ok, well since this build doesn't seem as promising as I had hoped. Do you F22Master or any one have any better suggestions for a motor swap or just keeping my F22A SOHC and upgrading it's internals? I was aiming for a DOHC vtec engine, but I'm open to suggestions. Let's say my budget for the engine is 2500 if I install it myself(I've installed Honda engines before).
11-05-2014, 12:07 PM
#12
Re: Turbo set up for F20B DOHC?
Ok, well since this build doesn't seem as promising as I had hoped. Do you F22Master or any one have any better suggestions for a motor swap or just keeping my F22A SOHC and upgrading it's internals? I was aiming for a DOHC vtec engine, but I'm open to suggestions. Let's say my budget for the engine is 2500 if I install it myself(I've installed Honda engines before).
11-05-2014, 12:19 PM
#13
Honda-Tech Member
Re: Turbo set up for F20B DOHC?
What I meant by my post was, F20B longblocks are so cheap and easy to find, its not worth spending a ton of money building one that will still probably have issues...
Just buy a stock one, boost it, run it till it craps out, buy another one, and part out the broken longblock to help pay for the.new one lol
Just buy a stock one, boost it, run it till it craps out, buy another one, and part out the broken longblock to help pay for the.new one lol
11-06-2014, 07:34 AM
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Re: Turbo set up for F20B DOHC?
What I meant by my post was, F20B longblocks are so cheap and easy to find, its not worth spending a ton of money building one that will still probably have issues...
Just buy a stock one, boost it, run it till it craps out, buy another one, and part out the broken longblock to help pay for the.new one lol
Just buy a stock one, boost it, run it till it craps out, buy another one, and part out the broken longblock to help pay for the.new one lol
11-06-2014, 11:57 AM
#15
Re: Turbo set up for F20B DOHC?
JSpec has the F20B for $895. JEI (local to me, great company) has the complete swap for $1795, but if you call them, I'd bet they would just sell the engine. Nagano, complete swap, same deal, $1650.
The engine is definitely out there and easy to find.
What turbo you would want to get depends entirely on how much, and what kind of power you want to make. For more engines, a cast log manifold and small to moderately sized turbo can get you good power on a stock motor and still maintain AC and PS - I don't see why that would be any different from an F, H, or "G" engine.
A Garrett GT28RS is always a good starting point to think from, when it comes to Honda 4 pots.
The engine is definitely out there and easy to find.
What turbo you would want to get depends entirely on how much, and what kind of power you want to make. For more engines, a cast log manifold and small to moderately sized turbo can get you good power on a stock motor and still maintain AC and PS - I don't see why that would be any different from an F, H, or "G" engine.
A Garrett GT28RS is always a good starting point to think from, when it comes to Honda 4 pots.
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