Background information:

I already have an EM1 with a stock b18b1 boosted making 298 wheel. So I thought I might as well drop in another motor when that one goes. I found this deal online for $400 that I couldn’t pass up.

It was a b18b1 block (stock sleeve) and a ported b18b1(Basically built) non vtec head that I picked up for super cheap, even came with new BC stage 2 cams, valve springs and a few other things.



I wanted to use this for a turbo build, which will get all the necessary ARP hardware but recently I have ran into a problem.

I was first going to run forged b18b1 rods and Nippon turbo pistons to net me around 9.5/9.8:1 compression… The problem is, is that I cannot find the b18 rods anymore, but I do have forged b16 rods on hand. I also haven’t purchased any pistons yet.



So here is my dilemma.



I can purchase the Nippon turbo pistons and then repurchase forged rods. I really don’t want to reorder rods that I bought brand new last year.

I can purchase used Wiseco pistons for $400 and use the forged b16 rods, which will net me a solid 9.0:1 compression. These pistons have a +8.30CC and are considered high compression, but due to the shorter rod, it drops down to 9:1.



I’m leaning more towards using the b16 rods as I have them on hand but I need some more input. Everything checks out on the Zeal compression calculator.




This is a B18b1 block and head with b16 rods and high comp pistons with +8.30 cc

 

Ummm.. This is the same. I'm no mathematician or anything but...

 

Well what I meant is that its a high compression piston, where in a full B18b1, would be close to 12:1 compression. But due to the shorter rod, the compression calculated drops to 9:1.

I hope that clears that up.

 

Ultimately, you want high compression turbo? I wouldn't suggest higher than 10.5:1, MAYBE 11:1 if Christ himself was tuning it; and I certainly wouldn't recommend any cast pistons at all, even IF it was tuned by God..

 

I don't really care for a high compression turbo build right now. Just looking to see if this setup will work with B16 rods and a 9:1 compression ratio.

The Nippons are cast while the Wiseco's aren't. The Wiseco's are also $400CAD which isn't bad right now, that's why I'm leaning towards that option. I really dont wanna dish out a lot on new pistons.

 

real street performance has the B18b connecting rods from eagle on sale for $336 right now

 

That's $336 USD to CAD its $447 plus shipping / import fees, we are looking at $550 all said and done. On top of that $550, I'll still need to buy pistons, which is why I'd like to know if this setup would work, If anyone can see any issue with this build.

B18b1 block, B18b1 head, B18b1 crank, B16a2 connecting rods and a forged piston with +8.30cc <-If i go this route, I'll have a 9:1 compression ratio.

Pistons which I'm getting for $400 used, 200 miles on them : https://www.tunersports.com/wiseco-s...1ap_p5249.html

 

9:1 CR can work just fine. Keep that in mind when selecting the turbo though. You'll not have lots of lag to worry about. The higher compression helps with low end and a bit with spoolup. 9:1 compression should still feel decent with a 45-55lb/min turbo with a .63 A/R, no prob. Anything higher/larger (turbo) will begin to feel sluggish down low. Besides, with lower compression, you can always turn up the boost a bit more to compensate!

 

Thanks a lot Txdragon.

I already have a high compresson N/A build you can see here:

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I was thinking originally to do a 11:1ish compression build but then after checking out this forum thoroughly, I see that low compression (around 10:1) has its benefits. Considering I'll be tracking it, I don't want to have "High Compression" turbo issues.

And I know 9:1 can be seen as low but I'm sure that head as been milled a few times and I'll be getting it resurfaced before assembly, so I have a feeling it will be around 9.5:1, but ill know for sure after the machine shop does a measurement.

 

‘if your running e85 10.1 is ok any higher you better know your tuning skills. I’d stay 9.1-9.5.1 if on 93oct and 9.1 if 90-92oct

 

Hey TurboLScrx,

I wont be running E85 as that's hard to obtain here in Toronto.

I will be running 93 Octane and this should come out to a minimum of 9:1 compression.

Also I'm not worried with the tuning as Dynamotor Sports will be doing the tuning / TonyTheTiger here on the forums

 

hmmm... mismatch crank and rods.... this won’t go good.

 

Would the b16 rods not fit on a b18 LS crank? Please spread some insight...

 

B16 rods are designed for a 77.4mm crank with a deck height of 204mm.

An LS B18 has an 89mm crank, and a deck height of 212mm.

No, you shouldn't use high compression pistons designed for NA use to try to "make up" for this obscene loss of compression you're creating. Get the proper rods.

 

Hey Chance EG,

I get I should't do it but is there any known issues with doing so?

The most I can think of is the piston possibly touching the crank, where a machine shop will have to remove material and re-balance that crank. That's if the skirt can make contact with the crank.

Also the piston is forged, so heat wouldn't be a factor, compared to cast when we are talking about the dome.

 

I no longer have the patience to deal with things like this. If you want to try it, knock yourself out, don't ask us for help or insight when it fails.

 

the whole build sounds overcomplicated. and i recommend not using nippon pistons. i used a set in my b18b turbo build and every piston was a different diameter. significantly enough that the machine shop had to bore all cylinders with different tooling. spend the extra 300 for good shelf forged pistons

 

If you have money to throw around then my friend go for it and let us know how it turned out.
but if your on a budget then I wouldn’t even mess with it, otherwise get ready to spend more tearing it back apart to rebuild again. There are other better setup on here that would make same power or whatever your needs are, that has been proven. Keep it simple and what combo that has been used well over time.

 

Co-Sign

 

Your pistons are going to sit in the bores about 1/8" DEEPER than they should... and you are trying to make up that flaw by using a huge N/A style dome-top piston. Your quench area will be ****... promoting poor combustion. A huge dome top piston is not optimum for forced induction and pump gas... you will be limited on ignition timing and this will cost you HP. Are you seeing a "trend" here ?

From everyone who has responded, the answer has been NO. There is a reason they said this and nobody owes you an explanation why. Trust me, you should just accept it and follow the current tried-and-true recipes.

I have humored you and given you solid reasons why you should get a set of LS rods and a flat top style piston... or a short, broad flat style dome piston if you want to keep the boost down.

... or you can ignore all that has been said here in this thread and do it your way... and regret it later.

 

And this is why I brought it to the forums to get some better insight. Thanks everyone for the input. That makes a lot of sense that the quench area will be trash due to the piston being lower in the cylinder.

With that being said, it looks like I'll be going the B18 forged rods route with Nippon pistons. I just hope their all the same diameter....

 

Why hope? We suggested earlier notto get them... Then you don't have to hope at all.. C'mon, man... C'mon..

 

To be honest, this is the first time I'm hearing that Nippon pistons are being sold with different diameters. Something like this shouldn't happen at all.

 

im not saying that one was 81.5 and one was 82. im saying that the quality control is garbage. some guys get lucky and some dont. mine cracked a ringland after 1000 miles of use.

 

****... Maybe I should just leave the stock B18 in there for now. I cant justify spending $800 on forged pistons and buying another set of B18 rods on a non-sleeved block. I'm going to have to keep searching for piston deals...