Pistons and cylinders are shot.. what to do now? Resleeve?

[Dimer]

I just heard from my engine builder that my cylinders have an average deviation of 0.7mm. My pistons are shot, so they have to be replaced. Two questions come to mind, with a CTSC, is it wise to go low compression 9:5:1 with a 9psi pulley?

Bigger, more important question. Do I need to resleeve the engine or can we bore the cylinders?

 

[BATMANs]

I'm running 9.2:1 at 13psi on 91 octane pump gas with no issues at all.

Dyno Tuned of course on AEM EMS 2.

Just honing the cylinder walls for fresh surface is all that is required.

NA1 doesn't need new sleeves since the NA1 are steel from the factory.

I'm running SOS SC and making 440rwhp and 305 rwtq on a Dynojet (the one with the rollers in the ground).

 

[chussey]

Just honing the cylinder walls for fresh surface is all that is required.

NA1 doesn't need new sleeves since the NA1 are steel from the factory.

I would imagine that a re-bore will be required with a deviation of 0.7mm.

 

[costa]

my block is still stock i have 9:8:1 cp piston running 14 pound of boost on my BBSC and spraying 150 shot of nitrous on pump gas and no issues here
have this set up from 2008

 

[Dimer]

In the end new SOS/Wiseco 90.5mm pistons were enough. We are also replacing the valves, springs, LMA's and much more. So I'll get a brand new engine back

 

[ScienceofSpeed]

hi Dimer -- Glad to help support your build. Let us know if you need any help along the way.

 

[Dimer]

Thanks! Also for the insane fast shipping! The engine should be almost ready, I hope this week.

 

[MvM]

Nice to hear things are going well.
Am very curious to see the final result

 

[Pchpleno]

Why such low compression? For such low boost on a forged piston I would try to keep the compression close to stock. My civic for example, I run a Wiseco piston at 10.8:1 compression and at 20 psi I make 502 whp. Compression is a good thing when tuned right, lowering compression for boost is a thing of the past.

 

[NA1MT]

Why such low compression? For such low boost on a forged piston I would try to keep the compression close to stock. My civic for example, I run a Wiseco piston at 10.8:1 compression and at 20 psi I make 502 whp. Compression is a good thing when tuned right, lowering compression for boost is a thing of the past.

Here we go again....why don't you try this with your NSX motor and report back to us with your results afterwards. On pump gas of coarse.

 

[BATMANs]

Why such low compression? For such low boost on a forged piston I would try to keep the compression close to stock. My civic for example, I run a Wiseco piston at 10.8:1 compression and at 20 psi I make 502 whp. Compression is a good thing when tuned right, lowering compression for boost is a thing of the past.

What octane are u preaching about?

 

[Pchpleno]

Ok settle down! I didn't post that to start any arguments.

I am building mine to be around the same compression. I'm talking about pump gas, the kind that you pump from any gas station. 91-94 octane I've used both on my civic.

Just to get tit out there I've been building cars for over 13 years. I've built my own motor anywhere from 9:1 to 12:1 and have run a broad range of boost levels on both pump and race gas. What I've come to realize is that Hondas work well with close to stock compression. I was just asking a question there's no need to get pissed about it and start a testosterone battle.

 

[CB72]

In the end new SOS/Wiseco 90.5mm pistons were enough. We are also replacing the valves, springs, LMA's and much more. So I'll get a brand new engine back

Hi Dimer, I hope your builder has inspected the cylinders very closely?
One of my friends here in France had one of his cylinders cracked and it's only by chance that they discovered the issue!
I personally think that using a compressor for track duty is a bad idea due to heat soak but you can always upgrade later of course.

 

[BATMANs]

My high octane pump gas is 91 octane.

Is that what you are running for your Civic with Wiseco piston at 10.8:1 compression and at 20 psi you are making 502 whp? Are you using any meth or water injection or is this just straight pump gas?

The reason why I dropped my CR a full point is for that margin of safety on pump gas.

I did research on various cars that are boosted from the factory to figure out the common range of CR that they are running.

I knew the MKIV at 8.8:1~ was too low and was having issues passing emissions here in California in stock form with the factory cats.

Ok settle down! I didn't post that to start any arguments.

I am building mine to be around the same compression. I'm talking about pump gas, the kind that you pump from any gas station. 91-94 octane I've used both on my civic.

Just to get tit out there I've been building cars for over 13 years. I've built my own motor anywhere from 9:1 to 12:1 and have run a broad range of boost levels on both pump and race gas. What I've come to realize is that Hondas work well with close to stock compression. I was just asking a question there's no need to get pissed about it and start a testosterone battle.

 

[Pchpleno]

Yes I use pump gas 91 octane from shell on my civic 4 cylinder 20 psi 502whp last year this year we're going for 540ish at 10.8:1.

Honda cylinder heads flow really well and the quench areas are really well designed so that detonation doesn't occur easily. You can't compare the heads on a Honda that are efficient to a mkiv.

My NSX build will be 10-11:1 with probably 14-18 psi on gt40 in pump gas, that's the goal

Here is a Dyno video http://youtu.be/wg9Pj5hbIFk

 

[NA1MT]

Yes I use pump gas 91 octane from shell on my civic 4 cylinder 20 psi 502whp last year this year we're going for 540ish at 10.8:1.

Honda cylinder heads flow really well and the quench areas are really well designed so that detonation doesn't occur easily. You can't compare the heads on a Honda that are efficient to a mkiv.

My NSX build will be 10-11:1 with probably 14-18 psi on gt40 in pump gas, that's the goal

Here is a Dyno video http://youtu.be/wg9Pj5hbIFk

Make sure you have that video camera handy when you run 18lbs of boost with 11:1 pistons on 91 octane for us. Have the sound enabled too so we can hear the detonation.

 

[doc_tai]

10.8:1 at 18 psi on gt40 u probably make close to 650 to 700 whp, that's too much for 91 pump gas. E85 would be nice

 

[Pchpleno]

10.8:1 at 18 psi on gt40 u probably make close to 650 to 700 whp, that's too much for 91 pump gas. E85 would be nice

Your probably right it would make that kind of power I might have to keep boost down. I think 600-650 should be ok on pump gas. 600 for sure.
If my 4 cylinder can make 500 a 6cyl has to be able to hold 600 at least. E85 isn't available at the pump here in Canada. Not like the states at least.

It all comes down to making the power efficiently. It's similar to everyone telling me not to run a huge exhaust housing on my civic because I'd have a lot of lag...so not true. My car has minimal lag and never drops out of boost. I have a undivided t4 .82 housing on it. That's where the compression comes in to play.

The closer you can make a boosted car act like an all motor car the better

 

[Pchpleno]

But back to the op topic.

I just heard from my engine builder that my cylinders have an average deviation of 0.7mm. My pistons are shot, so they have to be replaced. Two questions come to mind, with a CTSC, is it wise to go low compression 9:5:1 with a 9psi pulley?

Bigger, more important question. Do I need to resleeve the engine or can we bore the cylinders?

For that boost level on a charger, and the power your going to run, my opinion is get a forged piston that is close to oem compression or just slightly lower. A deviation of .7mm is calling for almost 1mm oversized pistons. I would have your engine builder check those walls closely for cracks. The smallest of crack can cause such a headache later.

 

[A.S. Motorsport]

Block has been inspected by the engine builder,
Also the low comp isn't such a bad idea with future mod's planned.

On subject of heat soak,
I hear your point! although I could modify it to fit a intercooler we'd run into roll cage clearance issues big time.
That + time constraints and possible setup changes planned for the future

9.5 is just right it allows you to run a high boost pulley and run the SC to it's max.
If you where to re do the FI setup and add more boost you could.

BTW, I'm all for high as possible comp (fuel permitting off course)

 

[MvM]

Block has been inspected by the engine builder,
Also the low comp isn't such a bad idea with future mod's planned.

On subject of heat soak,
I hear your point! although I could modify it to fit a intercooler we'd run into roll cage clearance issues big time.
That + time constraints and possible setup changes planned for the future

9.5 is just right it allows you to run a high boost pulley and run the SC to it's max.
If you where to re do the FI setup and add more boost you could.

BTW, I'm all for high as possible comp (fuel permitting off course)

On the subject of heat soak, me and Rene have discussed this with another NSX-friend (Marcel from Terneuzen) who can build wonderful things with his 3D CNC-machines (he manufactures aluminum sailing yachts stuff).

We are looking at building our own intake gaskets to isolate the compressor from the engine block.
Might not be enough on very long runs of course, but every little bit helps here.

Rene is sourcing the right material at this moment. It should raise the compressor more than about 6-8mm so it will even fit under the brace for those who have a NSX-T.

 

[A.S. Motorsport]

I already have a prototype for that.