MikhailBjornson

I recently bought a built car and want to eventually boost it. I want to fully understand the capabilities of my motor before committing to boosting the car.

I own a 96 Honda Accord Ex and it is H22 swapped. Darton sleaved block, 12.5:1 cr, domed forged pistons, skunk 2 valvetrain, stage 2 crower cams all motor app, aem adjustable cam gears, brass valve stem seals, port polished head, skunk 2 intake manifold, dc sport header, unorthodox under drive pulley set, urethane engine torque mount, stage 2 clutch, fidanza lightweight flywheel, and some other suspension mods.

The guy I bought it from said that it was ready for boost and I mostly trust him with all of the mods but I want more than one person's opinion on it. I know you can run high cr and boost but you just have to approach the boosting part a bit differently than lower cr. I've constantly heard people say that I can't turbo the car with that high of cr but I've also heard people who have done it but they just keep the boost levels low. I want to keep the cr on the high end, boost on the low end, and still run 93 gas. I won't be boosting for a while but I want to be ready when the opportunity comes my way.

Thanks!

TheShodan

iTrader: (14)

I wouldn't. Get better connecting rods at least. Tuning better be spot on, if 12.5:1 I'd the plan on E85. But not on 93 octane..

MikhailBjornson

I forgot to mention I had eagle rods as well although I doubt it would make a difference for the cr issue. A mechanic mentioned something very brief to me about doing something much simpler and cheaper to my engine that would lower my cr without swapping pistons. Does anyone know of a method that would be reliable for a turbo application? I would love to run E85 but sadly there are not any stations close enough for daily driving. Thanks!

TravisBiggie

um no, changing the pistons to lower the compression is the only way, besides getting a new head, but the difference is minuscule.

where do you live? If you have access to e85 in your area, go that route. if not, change the pistons, just like shodan said, i wouldn't use 92-93 octane with those pistons on boost

MikhailBjornson

Yeah unfortunately I don't have very easy enough access to e85 to have a straight e85 build which is why I need it to run reliably on 93 as well. Well looks like I can boost it but does anyone know what cr I should go? I want to stay on pump gas while also keeping the cr on the higher end. Thanks

Chance EG

If you could find a way to fit some sort of a supercharger on there, especially a Rotrex unit, then you'd be 100% made.

You can supercharge on high CR a lot easier than turbo.

MikhailBjornson

How would it be easier on high cr considering there is still boost going to the engine?

Chance EG

Boost is linear and constant, I'm sure there are other details. In the end though it's still the same thing, boost is boost and will affect CR accordingly.

Look into people with K series that are running Kraftwerks Rotrex kits. A lot of them are on 11->12.5:1 CR and running 93 octane. I can't see why this couldn't be done on an H22. You may be a bit more limited in PSI, but I think with a good tune you should still be able to get something great and reliable.

The problem for you would be mounting the SC and clearing the hood/accessories with an H22, and then you'd need custom piping. I don't think any SC kits exist for the H22.

Edit: On that last thought, just changing out to some lower compression pistons would probably be more cost effective as well.

gabocastano

You can also run water methanol and keep the boost low. Ask your tuner. All depends on your power goals.

2kdrift

12:1 is not completely out of the question, depends on power goals and most importantly your tuner and what they are comfortable with. Pistons is not the ONLY way, head CC and head gasket also effect it but not by much. You could possible go the HG route to get it just under 12:1 but ultimately it will still depend on the tuner and also power goals.


are you absolutely sure your on 12.5:1? just because if thats what the pistons say on the outside of the box, its not specific to your particular engine. Head/block milling and decking are probably the most important factors for you, my engine was affected by milling and also using a b16 head which does lower the Cr a lil bit

best to get the specifications of the pistons try to figure out total deck/milling and punch that into http://www.zealautowerks.com/hfseries.html

Aradin

Too much compression and too much cam to be boosted reliably on pump gas. Even with water/meth or E85, 12.5:1 static compression leaves little room for error and the domed piston shape isn't ideal for boost. You may be able to dial out some overlap with the adjustable cam gears but I doubt you have much room to play with. Another thing to be wary about is the wrist pins. All motor pistons are made with all motor applications in mind so usually a thinner pin is used to save weight but they are absolutely a weak link in higher torque applications(such as being boosted).

If it were me, I would either A.)Leave it alone and go with a nitrous setup or B.)Replace the pistons with a flat top or dish style piston that would bring the engine between 10-11:1 compression and swap the cams out for a set of stock ones then boost it. You can always sell your current pistons and cams to recuperate some funds if needed.

JRCivic1

What about having a competent machine shop mill the dome off the top... reducing the effective compression AND making a dome shape more suited for boost. This is all predicated on the assumption that the underside of the dome doesn't get thin once it is machined.

2kdrift

even if this was possible which i have my doubts easier / cheaper to buy new pistons and sell the old

JRCivic1

There is some truth/logic to that.

MikhailBjornson

And I'm sure there is less risk in just getting new heads than it would be to get old heads machined. I'd like to throw out there too that I don't have a lot of money so I'd much rather do everything the slightly more expensive way but have confidence that I'm not going to get screwed over.

MikhailBjornson

Why would I need new cams? From the research that I've done, the cams seem to be perfect for the application while getting stock cams would seem like taking a few steps back. Also this is a street car and might be something I could take to the track one day but is definitely my daily driver so a nos setup is kinda outta the question.

Aradin

Those are good cams for your current NA application, yes. I'm sure they are helping you make power in NA form. Adding boost to the equation changes the whole game. NA cams have a lot of overlap, which is when both the intake and exhaust valves are open at the same time. In an NA engine, that's ideal. In a boosted engine, it is not because it essentially creates a boost leak within the combustion chamber and can open the door to all kinds of nasty things like more detonation which is something you already have a very small threshold against considering the engine setup and desired fuel. Ideally in a turbo engine you want big lift with a short duration to maximize the engine's effectiveness. You could keep what you have and dial out some of the overlap with your cam gears but you're going to be very limited by your piston-to-valve clearance with your current pistons. H series have fairly large cams in them from the factory and can struggle with things like exhaust reversion even in factory form if the turbo setup isn't ideal. The way your engine is setup is going to amplify issues like that so "downgrading" to the stock cams will help alleviate some of that. Alternatively you could look into getting a set of actual turbo cams. There's a reason there are different things sold for different setups. Turbo vs NA cams, pistons, etc etc.

There's really nothing wrong with having a nitrous setup in a street car if it's done right. It would be much cheaper outright but eventually you'd catch up in cost over a turbo setup filling up the bottle. It's going to cost $3-4k minimum for a decent turbo setup in the first place, and that's without cracking into the engine and making the setup work with it well.

Peng0

at back side this dome looks like dish for weight loss, so if you will mill them at best scenario weaken the structure in the worst will make a hole...

MikhailBjornson

Thanks for the information. I'll ask the guy who I got the car from because the stage 2 crower cams can come in a couple of versions and one of those versions is a forced induction version. I believe I have their forced inductions cams which again I believe reduces the overlap. If i am not mistaken a nos setup on the streets of virginia is illegal but I am not 100% about that.

MikhailBjornson

Nope I have straight all motor stage 2 crower cams.

Aradin

That was the impression I was under because that's what was in your original post anyway.

So you pretty much have your options. You're not going to be able to have your cake and eat it too unfortunately. That engine was clearly built with aggressive naturally aspirated performance in mind and isn't well suited for a turbo application. You're going to have to change some things out to make it more boost friendly, leave it alone, or use a highly knock-resistant fuel and pray.

TheShodan

iTrader: (14)

MikhailBjornson

Yeah, I just talked to the guy who built the engine and that was more of the goal. I'll end up focusing more on the suspension and getting all my power to the ground consistently before I start adding any kind of boost to the equation. There are also a few other mods that I should do to get the most out of the engine in its current state. I thank everyone for the help and I will come back to this thread when I do decide to boost the car later.

TheShodan

iTrader: (14)

Anymore "mods" you think you'll plan for that engine, and you might as well stay NA for the whole engine. Get another engine and start over, my friend. you're already at the highest reasonable cost limit.

2kdrift

IMO either save up to boost it properly or enjoy what you have, dollar per HP turbo is so much cheaper, you can only do so much HP on a NA setup