BABY NSX

Earlier this year I started down the road of rebuilding my aging B18C. The engine had been built in 2007 and with plenty of high strung driving under it I felt it was time to freshen it up again.

After pulling the engine I decided to have a look inside:

Cylinder walls showed some wear...

Yikes... look at these pistons - rebuild just in time:


My original sleeves have seen enough action... lets do this:

83mm pistons and sleeves installed:

Head was reworked by 4 Piston Racing - combustion chamber looking good - had to open it up a pinch for the pistons

Look at those ports:

Engine back from builder (Lawrence Built)


And she's back in:





Time for the first round on the Dyno:

Not a bad result from the first day:

Found a problem with my ignition on the Dyno,... after a second day on the dyno and with some new additions (coil pack retrofit and new 70mm TB) I've got some new numbers:


About a 9HP gain from the previous day... not bad and I think the engine is delivering the goods now. only a 1.9L engine with modest compression (11.5:1 CR). That said, I'm interested in feedback on where I may have room to make more power, I am not particularly happy with the midrange results, but not sure what the next best move is to flattening out my torque curve.

Video of glory run at end of day:

Build details:

Top end stuffs:
- 4 Piston Racing Outlaw CnC head
- Skunk2 Pro series valves and valve train
- Skunk2 Pro2 cams
- Skunk2 cam gears
- Skunk2 ultrastreet IM
- 4 Piston Racing CnC porting on Skunk2 IM
- Skunk2 70mm TB
- Mugen intake
- Samco intake pipe
- Skunk2 composite fuel rail
- Grams 550cc injectors
- Skunk2 Mega Power Header
- Skunk2 has 3" exhaust

bottom end stuffs:
- Wiseco 83mm 8cc pistons
- Carrillo Pro-A ultralight rods
- 4 Piston Racing high RPM oil pump
- lightened ITR crank
- ATI harmonic dampener
- Aluminum Flywheel

Tuning:
Hondata S300
Hondata Coil Pack Retrofit

Thanks,
Doug

ontariorider

BABY NSX

Thanks for the feedback! I used to live in the GTA but have since moved myself and the car to California. Eric and I go a long way back and I enjoy representing his company out here on the west coast.

240+ WHP I think would be a pretty ambitious target given the fuel I have to run on a daily basis here. The 91 rated fuel here is not all that great and it does put a cap on how much compression and timing you can safely run. I believe with the 94 I was running in Canada I could likely hit 230 with my setup as it is.

I am looking to swap out my exhaust setup with something from Hytech or similar. I'm in communication now and will likely pull the trigger on a new setup soon. That will likely go a long way to cleaning up my torque curve and perhaps net me some more peak power.

I'll likely play around with different intake setups but I do like the cleanliness of what I'm running now - still it would be nice to know what might be holding me back.

Doug

2x0

Why Darton sleeves with no boost? Why not just bore the stock sleeves over for the rebuild?

Otherwise, pretty impressive output!

1HGEJ2

iTrader: (1)

vtec is at 6800??

the_unknown

Well looking at the car (MINT ITR) and the parts selections (4piston, Carrillo, Wiseco, we'll excuse Skunk2 here, they do make some good cams/IMs...) looks like the guy doesnt skimp on things and wanted to overbuild. If I was going all out on a car I planned to keep I would have done the same. For some people "good enough" is not enough. I agree, it is impressive.

Looks that way doesn't it? I remember my first LSVtec build in an EG hatch, had a "Mugen" chipped P28 that had the Xover at 6200 on a completely stock GSR head/cams. On full throttle when Vtec kicked in it sounded like it just fired up another 4 cylinders or something, lol. It was very nearly passable as violent and while being completely pointless and detrimental to power, everybody freaking loved that thing including me! This was in 2003 so I didnt know better at the time but it was quick for what it was.

I would like to believe whoever tuned this car knows better than that though. I think the Pros have good size primaries so the midrange is healthy but almost 7k Xover seems strange to me..

AllMtrRex

Velocity stack, 4"-transitioning to a 3.5" intake. Try a header with a larger collector. Possible the intake side is the restriction and with the 4P head it needs more air and more revs. This was on 91 pump? I don't think there is much more left in it on 91. Change the intake, and e85!

BABY NSX

All the above is true, and thanks for the comps on the ride - I've been trying to keep her clean for 20+ years...

The VTEC point is indeed at 6800RPM... it was set there because that was where the natural transition point was in the torque curves. We definitely tried lower and even a little higher to see if there was a way to recover some of that loss of torque in the upper midrange. 6800 was the best place for us to set it and had nothing to do with trying to create any VTEC kick. I have a feeling that as I look for solutions to increase midrange torque, I'm going to be loosing some top end power.

Moving my fuel cut to 9,300-9,500 RPM should allow for some decent power delivery through the gears as the engine will remain above 7,000RPM... Having some more torque bellow 7,000 would be helpful when pulling out of slow corners when I don't want to be in a shorter gear... but I generally like to have things spinning quickly.

Regarding Skunk2... I know they have mixed reviews here and I too wondered how well their header and exhaust (for example) would allow my engine to breath. I was pretty impressed that the engine delivered what it did with parts people often view as inferior. Maybe more power could be had with a more custom exhaust setup, but I don't see room for anything more than single digit gains and/or simply moving where the engine makes power. As for their valve-train components, I'm using their pro series parts which, I believe, are on the same level as other top shelf parts from suppliers such as Ferrea (which I used in my last build). Anyway, I don't feel like I cut any corners by using Skunk2 parts in my build.

BABY NSX

Yes, this was on 91 California pump gas... I don't think there was much more room as we were pulling timing to keep the engine happy. I agree that work done on the intake side would likely deliver more air to a hungry head. I am trying to think of a way to put something together that will blend in well with the engine compartment layout I have - perhaps simply replacing my samco intake with something a bit larger would help - as my Mugen intake already has a decent velocity stack on it.

Doug

AllMtrRex

That's what I would do. Unfortunately, this is the nature of a 83x89 vtec B-series. I feel your torque numbers are spot on for your parts combination and fuel. With the addition of a 4P CNC head and Pro2 cams. These parts are designed to swing the power to the right without killing torque completely but you will def not gain much, if any down low.

I agree, your parts selection was top notch (If you were aiming for high rpm power) I would switch the intake and change fuel (Pick up another 15-20whp) and rev this combo out to 9-9.5k.

the_unknown

I thought the VTEC was set there for a reason and that's why I mentioned the Pro2s primaries. I could tell from the rest of the build whoever you had tuning it was smart enough for that. And I wasn't implying you wanted to tune in the VTEC "kick" just sharing my story regarding it. Pretty sure my P28 wasnt compatible with the stock GSR manifold my car had either so the secondaries not opening up made the transition that much more pronounced, oh the good ole days!

Skunk2 has a bad rep for many reasons, but that doesn't mean they don't or haven't made good parts. I'll spare the backstory as you probably know a lot of it anyway. As I conceded earlier, their Pro line cams and Ultra IMs are top notch, and the headers are insane value for the money. Now putting their valvetrain components in the same context as Ferrea??? That's beyond what I would consider a stretch, but as long as everything works and you're happy, I'm happy for you. What works, and what is the best, are not always one in the same.

I agree with the intake portion. Not sure of the specs on the Mugen but a nice 4" velocity stack with transition to the throttle body would be nice. Also look into the 4piston CNC port on the Ultra manifold you have. Could give you some nice gains.

While the Skunk2 header is a great value, I think a properly designed custom header for your application would likely give you more of a bump than you think.

While I agree with everything here, to some extent you can play with the powerband a bit using the cam timing. I think you know at this point your options to gain much more power in any part of the powerband are very limited.

Casey

iTrader: (5)

Nice numbers. Also to the person that mentioned why sleeve...you cant bore 83mm safely on a b18 block. I think the numbers shouldnt worry you too much. I would say try a different header for sure, and as others mentioned open up the intake side. I am doing a less aggressive rebuild(head only) this winter and plan to keep my mugen intake. At 190whp it was not a restriction over a 3" open aem ITR with no filter, but at your levels it could be partially hurting power, but easy to find out and then decide if its worth it for you or not

Chance EG

Beautiful car, and very clean looking engine as well. Excellent street N/A build.

Hope you can squeeze a few more mid range ponies out of it if that's what you're after. Piston dome and compression ratio could have been a little bit more aggressive than what you went with IMO, but I've always been tuned on 93 octane and never been limited on 91, so I don't know how much harder the knock threshold or timing events are to handle there. From skimming the comments I think there should be a way you could drop the VTEC engagement point by a fair amount, but I'm not sure out of your current build components or tune as to what would let you do that. Pro2's on ~11.5:1 compression are a little bit of a stretch I think, not sure if that's why your VTEC wants to kick so high.