This has probably been asked a billion times on here but I didn't see much on it in my search, and I want is some opinions...

I have my deceased little brothers car that I'm building (went byTurbodcx on here) and what I've got is his Darton sleeved 84mm B18C5 block, a set of type R 84mm pistons (RS machine) and I'm deciding on what crank and rods to use...

I have both an LS crank and Type R crank, I like the 89mm stroke for that extra torque but is the LS crank as strong? Is the extra couple of mm's stroke worth it? From what I understand I can use my current pistons with either setup as long as I match the rods/crank.

So what do you guys suggest? Go with B18B rods and have a 89mm x 84mm 2.0l or keep the R crank and go with B18C rods and rev the **** out of it? All motor for now, maybe some boost down the road.

 

If you are even planning/thinking of boost in the future then the answer is simple, use the type r crank and not the LS. The LS crank with those pistons will make a high compression ratio when on the boost CR spectrum @ 12.9-13:1. That is too high for my liking for a DD/street car anyways. NOW when using the ITR crank with, rods and pistons you're looking at a CR at around 11.4-5:1. IMO that is a perfect number for a street NA motor (likes pump gas still and is reliable) as well as carries many different selections for cams that will be mild and make great power still. I have seen a bone stock JDM ITR (11.3:1 CR) boosted and making 400+whp and its been running for over 2 years now. The fact your block is sleeved is crutial. There are countless possibilities....just depends on your budget and overall goals. A 400whp turbo motor out of what you have listed w/o going forged would still be pretty easy to accomplish if thats what you want in the future.

 

Ok, so are you saying with the LS crank/rods that the dynamic compression is going to be higher? Because the static compression should stay the same, the pistons and combustion chamber volume in the head remains the same regardless of what rod/crank is used. I don't want to go over 11.5:1 because I do want to run 93 pump fuel, no race gas.

However, being a V8 guy, I like torque, so I think I'd really love the additional torque of the 89mm stroke with the 2.0, I don't really want to have to rev this thing to the moon to get any power from it (I know Hondas have to be spun high anyway but I don't want it to just start making power at 6000rpm either) I have a stock B20Z in my Integra and I'm amazed at how well it pulls for a 2.0, my old hatch with a GSR swap had to be downshifted so much just to get it to pull the mountains up here.

 

If you use the LS crank your compression will be over 11.5:1 and be in the area of 13:1...which IMO should never see pump gas. The ITR crank would be your best bet for keeping the compression ratio you want, and trust me you wont be downshifting to pull hills, I dont with mine. The transmission ratios of the GSR have a slightly longer FD and 5th gear compared to the ITR tranny (im assuming your using it) which will put you at 3500rpm doing 65 and will pull just about any hill in front of you. Im a V8 guy as well, check my sig.... but the TQ gained will not make or break you. I have run both setups (LSV and ITR) and I like the ITR much better.

 

Alright, so you are saying the dynamic compression will be really high due to the increased stroke, makes sense. I'll just stick with the ITR crank and rods. I wanna be able to drive this thing around and take it to memorial cruises and such.

Thanks.

 

I think it's 13+ compression in the LS block which has a shorter deck than a GSR...


Zealautoworks says your pistons with 89mm stroke will be 12:1 with a b16 head and 12:4 with GSR gead. Compression difference is really minimal between the two cranks. 87mm stroke is 11:9 with b16 head and 12:2 with GSR head. I'd go with the 89mm stroke. Don't worry about it not able to rev high enough. I've seen numerous 89mm stroke spinning 9500 RPM. There is nothing to worry about the LS crank will be as reliable as the ITR.

 

The LS block has a taller deck the the GSR.
Your numbers are off....and you have to consider hes using 84mm pistons which also make compression increase.

I did realize I put ITR rods on the LS crank to make compression a bit high, but he wants the CR at 11.5:1 or lower. LS crank will make it 12+

 

You can get 13:1cr to run on 93 with a good tune.
The extra torque will be real good for it and if you get arp rod studs and get the rods shotpeened you can rev it fine.

The only question would be are you serious about going boost later, if you are the R crank would be very worthy

 

How are u guys getting 13:1 cr ? Static I'm assuming. With w.e stroke you'll pick you'll be fine with. IMO stick with the ls that extra 2mm ain't gonna hurt you.

 

Getting Eagle or Manley rods so no issues there...

I would love to get 12.5-13.0 compression to work on the street, I think it can be done with a CAREFUL tune and a nice, clean deburred combustion chamber from what I'm reading.

 

Using that Zealautoworks calculator I'm coming up with 12.1 compression using LS crank/rods. I think I may just try the LS crank/rod combo and see what happens! Should make a nice little motor.

 

Check again buddy. LS deck is slightly shorter than GSR. With neither crank he will be at more than 11.5:1 with ITR slugs.

 

There is a lot of assumptions being made in this thread....

You have to know what the "ITR style" pistons are rated for (comp wise) in an 84mm bore and what stroke it's rated at before you can accurately extrapolate what his final compression calculation would be. Even then, I would have everything cc'd to be sure.

I would personally use the 89mm crank and go with those pistons etc and I'd be willing to bet the compression ratio you'd end up with will be between 11.8-12.2:1, when everything is said and done. That is a great ratio for a street motor build like this.

 

They are just the RS Machine ITR copies, rated at 11.5:1 I believe...

I've made up my mind after much careful reading/research, I'm going with the LS crank/rods. I love the torque my stock B20Z has in my Integra.

 

Well that's the question...which ITR copies? USDM or JDM? The answer will affect the compression ratio quite a bit. If they're "rated" at 11.5:1, what block and stroke do they hold that rating in? The answer can have a big effect on what you'll actually end up with on a specific build.

OP- I'm just pointing this stuff out in general to others but I would go the route you're going now.

 

RS machine only makes the ITR copies in P73-A0 (USDM)

 

do we know how many cc's the domes are? compression height?

 

Do it!!