So, this is the first performance all-motor engine I'll be building. I've done basic rebuilds (LS/B20), but nothing high compression. My DB2 is aging and the 4th cylinder is about 20 lbs over compression. It's time for a rebuild this winter, and I've already started compiling parts for it.

I plan on using the original block and head due to the rarity of these vehicles these days. That being said, the B17 crank is really what separates it from the B16. I plan on using the original crank once I get it balanced and micropolished. I also plan to shotpeen and recondition the B17 connecting rods. However, I want to run the over-sized 82mm PCT pistons. I have the ACL race bearings (rod, main, thrust washers). As far as the head goes, I'm not sure if I should get a set of ITR cams, or some aftermarket staged ones along with a new VT.

Anyways, I haven't been able to calculate the compression ratio if somebody could help me out with that. I understand that I will need to be running higher octane fuel. Will boring out my block to 82mm with stock sleeves be a bad idea? The car is not going to be a daily driver (more a weekend grocery getter). Also, will I be facing any clearance issues piston to head?

I'll be sure to keep this updated as my build goes on, but any help would be much appreciated. Thanks

 

http://www.zealautowerks.com/bseries.html

 

Thanks! So I'm looking at a 12.74:1 compression ratio....

 

i would just go 81.5, no need to go 82. but, on stock sleeves i think 82 would be fine, shouldnt break anything.
why pct's? as for P2v clearance, you'll have to the clay the engine.
12:1 is pretty high, there was a local debate about running that compression w/stock cams and it was said that it wouldn't be a good idea. plus, it may not make the power you want.

 

Pct pistons just for the high compression/power. As far as cams go I want to do crower stage 2 cams, but will that cause me to do a full aftermarket valve train?

 

What does crowers site say?

 

Ya just went on the site and it says they require an upgraded valve train which is killer to my pockets...but I'm wondering if that's just crower staged cams. I'll have to check skunk2, buddy club etc

 

Also, jut for the record, I already purchased the 82mm PCT pistons so I'll probably end up going through with them. Just worried about p2v clearance now, like you said, I'll have to clay the motor. I'm also curious as to how much hp I'll be pushing, roughly

 

Bump

 

I'd be careful with the PCT pistons unless you have some higher octane fuel, that compression is pretty damn high. My friend had a b17a with PCT pistons and had to do some serious detuning to get it to run safely on the 91 we get here in CA.

Some good info here including all the specs and output on the b17a I built a few years back.
http://forums.g2ic.com/showthread.ph...st-your-builds

 

yeah, I am aware of the fuel I should be running. I can get 93 octane here on the east coast, and that is all I would use.

 

Just played around with the zeal autowerks compression calculator. Even if I did go with the 81.5 mm bore on the PCT pistons, I'd still be pushing 12.6:1 compression...

 

P73 pistons will bring me down to roughly 11:1, which seems more ideal. I might have to make a switch

 

If you want slightly higher compression look at the B16 pistons. I personally am a fan of the PR3's

 

Personally I always liked the p30 pistons. More compression than the p73 and less than the pct. Plus they fit the stock rods without modification whereas both the pct and p73 need the rods machined to fit. I ran oem standard oversized (0.25) p30 pistons in my motor.

 

I was thinking those pistons as well, BUT they do not make them in a 82mm bore. Trust me I looked everywhere when I built my last GSR. Finding 81.5mm was nearly impossible too. Thats why I said PR3, RS machines and a couple other companies have them readily available in a quality cast for good prices.

 

I will check out both. thanks for the input guys

 

I DID end up switching to the p30 pistons oversized at 81.5 mm. looking at 11:1. Much better. I like the idea that there won't need to be machine work to fit on the b17 rods

 

^Yup, that's a great way to go. I always recommend the P30's unless you're trying to build a really high HP (high compression) monster. Compression is really what makes the b17a so lackluster from the factory. It really is a great little motor once you bump the compression up and put some ITR cams in there. I used to call mine a "mini ITR motor" because it was basically ITR spec but only 1.7l :D

 

Where did u find P30's in .5mm overbore?

 

P30 pistons are a good choice. I'm currently running this setup:

- B16A2 block
- B17 internals (crank & rods + ARP rod bolts)
- 81.25 P30 pistons
- Block + Head milled by 0.01" due to HG failure
- All bolts, gaskets, hoses, bearings OEM Honda
- Head ports polished
- ITR springs and retainers
- EK9 cams
- OEM B16A2 intake mani + TB
- RDX injectors + AEM FPR
- Toda replica header + Top fuel catback
- OEM ITR airbox + K&N filter

My CR is around 11-11.2 and the engine feels very responsive and works great even with a basemap.

To give you an idea, with my old B18C4 cams (I think it's GSR cams in US) I was running a bit faster than a friend's EG6 weighted to 930kg with B16A2 IHE mods + Remap ... I have an EK4 with full interior and I should weight around 1080 - 1100kg. We have the same gearbox.

Next year I'm planning to go for:
- Fully P&P head with flat supertech valves
- Skunk2 Pro1 or Pro2, will depend on my CR with my new head
- Home made ITBs based on 4AGE quad-Throttles with Home made intake mani
- Profesional Dyno tune

 

My setup is looking to be like this:
-B17 Block
-B17 Rods, Crank
-P30 Pistons at 81.5
-Oem gaskets
-ARP head and rod bolts
-ACL Race bearings (main and rod)
-B17 Head ported and polished
-Crower St 2 Cams
-Crower Titanium dual springs and retainers
-Skunk2 Pro Intake mani
-DC Headers down to 2.5" straight pipe

And my car is already equipped with an s300

I'm still confused on what size injectors I should be running for this type of compression. I was suggested 550's, but I'm not really sure

 

You can run any size injector really, its not a crazy or intense build. I like running LOW duty cycles on my setups so I will run about 2 sizes too big and tune them accordingly. Check out the RDX injectors. They can be found for roughly $250 and comes with everything you need to put on the harness to make them work. They are 410's which will be more than plenty plus supposedly they net good gains due to their spray pattern.

 

Cool. Yeah, I don't want anything crazy because I want to keep this DB2 as original as possible while still getting power to the wheels. Thanks for the tip. I'll look into the RDX

 

Speedfactoryracing.net has FIC injector for $265 shipped in just about any size up to 440's. They are compatible with the OBD1 honda plugs with no mods as well. Buying from them you are supporting our sport and the guys there are top notch to deal with