Testament to the quality of an NSX engine

[Vega$ NSX]

For any of you afraid of high milage on an NSX...

The other day I took my car to Factor X to do a compression test to see how my engine was holding up. My car has always run pretty strong, but I always felt that the engine was a bit worn out. Perhaps because it is a '91, I'm the third owner, it is constantly redlined, and has just a shade under 150,000 miles on it. Let's just say the car is/was fully utilized, and then some.

For those that don't know, a compression test measures the pressure generated in each cylinder of your engine to see how well the piston seals with the cylinder wall. The manual says that 'nominal' is 199 psi and should not be lower than 142 psi. However, from what I've seen and heard, 200-230 is not uncommon and Mikey at Factor X says an NSX right off the lot is typically around 215. The other key (and perhaps more importantly) is that all the cylinders are within 5% of each other.

So what did a 150,000 mile NSX engine put out?

212, 210, 210
210, 215, 210

Not bad, and the only reason the 215 showed up is because there was a little bit of oil in that cylinder that helped the seal. I'm sure if we cleaned it up a bit, it probably would have been around 210.

Awesome results :biggrin: which is good because I'm a prime candidate for a turbo :biggrin: :biggrin: :biggrin: (more on that soon!) I was worried being a 15 year old car and with lots of miles I'd have to do an engine rebuild before going FI, but so far I'm good to go!

 

[Bigglezworth]

Honda/Acura's most expensive car certainly comes as a result of the best of the best in terms of materials and assembly. Good to see the numbers confirming what has always been obvious in my opinion.

 

[4AU4LIFE]

That is a great testament for sure.
I tested the compression on my Integra about a year ago and found it to be in top shape also. Although I drive the car very easy so I should hope it to be that way.

 

[MrTwo]

That is great news as I have just purchased a 91 with 85k on it. I love the NSX but I do feel a little strange when people ask how much I paid for it. But I don't mind because now I'm getting to live my childhood dream of driving a beautiful NSX whenever I want

 

[transdzn]

How much does it run to get a compression test? And can it be done at your local Acura dealer?

Good thread BTW :biggrin:

 

[4AU4LIFE]

How much does it run to get a compression test? And can it be done at your local Acura dealer?

Good thread BTW :biggrin:

You can do it yourself at home. Just have to get a compression gauge and the fitting to screw into spark plug hole if it doesn't come with it.
Any Acura dealer can do it also if you feel more comfortable that way. Also any local mechanic you trust can do it too.
I'm no gearhead by any means but was able to do this and a leakdown test by myself.

 

[Daedalus]

Yeah, not too much more work than changing the plugs. Best to do it with the engine warmed so parts are close to their running states.
Vegas, you alluded to the question but I'll ask it anyway: Won't going FI require you to replace the things that the compression test is testing? Pistons and/or rods need to be replaced, and no sense in using old rings. At least you know the valves are sealing well, but since the head has to come off to do the pistons/rods, you may as well have it freshened up with new guides/seals, and maybe new valves/seats, depending on clearances.

 

[AU_NSX]

Vegas, you alluded to the question but I'll ask it anyway: Won't going FI require you to replace the things that the compression test is testing? Pistons and/or rods need to be replaced, and no sense in using old rings. At least you know the valves are sealing well, but since the head has to come off to do the pistons/rods, you may as well have it freshened up with new guides/seals, and maybe new valves/seats, depending on clearances.

Why would he have to replace pistons/rods? Why would the heads have to come off?

The NSX already uses titanium rods so what do you want to replace them with???

You shouldn't have to take the motor apart to fit a turbo, bigger injectors or a new ECU.

 

[Daedalus]

Why would he have to replace pistons/rods? Why would the heads have to come off?

The NSX already uses titanium rods so what do you want to replace them with???

You shouldn't have to take the motor apart to fit a turbo, bigger injectors or a new ECU.

How much boost can you expect to give to an engine with a 10.2 CR? I assumed that's what Vegas meant by having to rebuild for FI. Not sure what you guys down under have, but the best gas we get in the states in 93 octane, 91 in some states, including CA. Racing gas is available, but very expensive (to us) and few stations sell it. Heads usually come off during a rebuild--how would you compress the rings to get the pistons into the cylinders from the lower end, let alone hone the cylinders or do anything with the valves?

 

[AU_NSX]

How much boost can you expect to give to an engine with a 10.2 CR? I assumed that's what Vegas meant by having to rebuild for FI. Not sure what you guys down under have, but the best gas we get in the states in 93 octane, 91 in some states, including CA. Racing gas is available, but very expensive (to us) and few stations sell it. Heads usually come off during a rebuild--how would you compress the rings to get the pistons into the cylinders from the lower end, let alone hone the cylinders or do anything with the valves?

You can run 6psi comfortably. even 9psi is possible on pump unleaded. So you don't need to do an engine rebuild!

 

[Vega$ NSX]

Thanks for all the comments guys. I was going to chime in, but it looks like all the other members got to all the answers before I could. :biggrin:

As for doing the compression test yourself it's pretty easy. I would say about 1 hr labor max. However, the hard part about it is all the specialty tools you're going to need to pull the job off, which I definitely don't have. Any place (i.e. any dealership or tune shop) should be able to easily do this for you. The way we did it at Factor X was to take the plugs out, disconnect harness on the engine wall by the alternator, gauge each cylinder and crank with clutch and gas fully depressed about 5 seconds. I would say take it to a tune shop as it's easier to do with 2 people, but it's not a hard DIY if you have the right tools. Do a search on "compression test" for a good thread on the procedures. I think it's good to do a compression test every once in a while or when you first get your car.

As for FI, no engine rebuild necessary as AU_NSX already mentioned. It is also the reason for the compression test to see if a engine rebuild was necessary. Since the engine seems to be pulling just fine I can just slap on FI (turbo or supercharger, or even NOS for that matter) without having to do a thing with the engine. If fact the weak link in the NSX is the clutch and then the transmission. Either one of them will go far before the engine will have problems. The Factor X NSX was pushing well past 15 psi with no problems. Last I checked, I believe it was at around 20 psi, but I could be wrong. You may want to ask them to make sure. The only issues they had was finding a clutch to hold up to the 600+ hp they were putting to the ground.

 

[SINCITY_NSX]

Hey Brian. What did factor x charge you? On another subject Jason told me you did the seats and door panels your self? We need to meet up one day so I can get you to help me with mine.

 

[Vega$ NSX]

Just 1 HR of labor which they said they would roll into the cost of the turbo install should we decide to go ahead with that.

I did redo my seats, man it was hard!!! One seat took me the entire day and my fingers still hurt like crazy. But, with the knowledge and understanding of how to do it, I think I can do it much much quicker and easier and they came out really nice. Let me know, I can even loan you the hog-ring installer and some extra hog-rings (I have plenty).

 

[4AU4LIFE]

Just 1 HR of labor which they said they would roll into the cost of the turbo install should we decide to go ahead with that.

Totally off topic here but I thought they (FX) wasn't doing turbos for consumers anymore?

 

[hk4site]

Leakdown test will tell you alot more than a compression test

 

[NetViper]

Just 1 HR of labor which they said they would roll into the cost of the turbo install should we decide to go ahead with that.

I know if I was in Vegas, I would have a turbo on my car. Hard to beat having factor X in your backyard!

 

[4AU4LIFE]

I know if I was in Vegas, I would have a turbo on my car. Hard to beat having factor X in your backyard!

Why?!?!? You would then have MB in your backyard also?:wink:

 

[Vega$ NSX]

Totally off topic here but I thought they (FX) wasn't doing turbos for consumers anymore?

Yes and no. I don't want to speak for those guys, but from what I see, they aren't a public/open shop. They still do business privately and I still get all my work and tuning done there. They relocated and are now just minutes from my work! :biggrin: :biggrin: :biggrin: