Honda D Series Forum banner

1 - 20 of 47 Posts

·
Registered
Joined
·
295 Posts
Discussion Starter #1
So i have had my JRSC on my car for a couple years and it's time for something different. Don't bother with the JRSC suck go turbo i already have a fully built DOHC ZC so i have my turbo fun as well. And since i've read a lot that the JRSC responds well to high compression i wanted to get some educated opinions on the subject. So i have a couple of thoughts. This is gonna have a fairly low budget, around 1000-1500. All options i'll be using a very low miles A6 block with LS rods, i won't be making monster horsepower so i feel forged isn't necessary. I will be updating to OBD1, supercharger will be sent in to be freshened up, i may even spring for a port job. I will also be using a water meth setup and running anywhere from 8-10 lbs. So here are the setups i was thinking about:
A6 block
Z6 head
A6 pistons
.030 headgasket
roughly 10.1:1 comp ratio

A6 block
Z6 head
ZC pistons
.068 headgasket
roughly 11.6:1

A6 block
A6 head
ZC pistons
.068 headgasket
roughly 11.3:1

So a couple things i was wondering, A6 head vs Z6 head, does either one have better flow characteristics or better suited for this build. Also this will be run on 93 octane pump gas so i want to make sure i don't go too crazy on the compression. I will have this setup tuned professionally, with the high comp and water meth it's beyond my realm of comfort. So i'd appreciate any info or if you have any questions on the setup please ask. Thanks
 

·
Registered
94 Del Sol si
Joined
·
489 Posts
Sounds pretty good, only thing I would up grade is the injectors if u haven't yet. Not sure what head will flow better since I only worked with z6's. Good luck and can't wait to see the numbers!
 

·
Registered
Joined
·
487 Posts
Everyone has their own opinions, but I would personally not boost a high compression motor. It's true, that it makes more power per PSI. But the margin for error in terms of tuning is very very slim and a small miscalulation will detonate that motor.

But if you really want to, I would choose to boost the 10.1:1 compression ratio. Anything else is just asking something to melt.
 

·
Banned
My car...
Joined
·
1,875 Posts
Any head can be milled to get whatever compression you want.

A6 = Better valve layout (exhaust valves not pushed out like on vtec heads)
Z6 = One of the best flowing (stock) heads, apperently.
Y8 = Quench pads!

What header are you planning to run?
Who would you have port the head (very important!)?
What cam do you want to run?
Why are you planning on running those pistons? Why not PG6's?

You need to look at the complete picture, oh, and SEARCH!
 

·
Registered
Joined
·
295 Posts
Discussion Starter #5
Any head can be milled to get whatever compression you want.

A6 = Better valve layout (exhaust valves not pushed out like on vtec heads)
Z6 = One of the best flowing (stock) heads, apperently.
Y8 = Quench pads!

What header are you planning to run?
Who would you have port the head (very important!)?
What cam do you want to run?
Why are you planning on running those pistons? Why not PG6's?

You need to look at the complete picture, oh, and SEARCH!
Believe me i search. I read a lot, i'm not a lazy ass like most people who want spoon fed answers. I like to research and understand things myself. I'm an older guy, i'm 32, built my first turbo Honda motor when i was 18, well before it was the "in" thing to do. But in all that time i've only messed with a few motors, i've never had a b-series motor. I'm a d-series lover at heart.

To answer the other questions, i'm running an Edelbrock header. My Z6 has a mild port i did myself, nothing drastic just cleaning up casting marks. Cam is undecided because so far thru all my reading no one has a concise decision on what cam makes better power with a JRSC. I was thinking about a Delta 272, maybe a Bisi stage 2. One thing i'm not well educated on are cam specs and what's good for which situations. I planned on running either the PM6 or PM7 pistons because i already have them, trying to purpose as many parts i have in my inventory as possible. At one time i could have built 3 complete 88-91 hatches with all the stuff i had. But like i said i'm a little older than some of you guys, i have a wife and 2 kids and a business to run, not to mention a new house i'm rehabbing to move into soon. No rest for the wicked
 

·
Registered
Joined
·
295 Posts
Discussion Starter #7
Older guy?? Your younger than me kid.....lol the w/m is a great idea with the build to kill detonation.
haha, yeah i know there are some older guys out there, but i'm older than most of these kids. And yes i'm a kid at heart, a 5 and 2 year old keep me young.

on the build, since supercharged motors have more of there power delivered in the low to mid rpms and vtec doesn't really engage until like 4500-5k, is it even worth going with the Z6 head. I was mainly gonna use it just for the compression bump. I just wanna build the most effective engine with the parts i have available.
 

·
Registered
Joined
·
295 Posts
Discussion Starter #9
Yeah my initial though was maybe vtec would help with a little more power up top, power kinda dies off over 6k. But i am a fan of the A6, one of my favorite motors ever built. I was thinking about trying both heads (with the ZC piston setup) out but i can't afford to get both setups tuned. At least with the A6 block, Z6 head setup i could try that now and see if i like it. If it falls short of my expectations i can always do the ZC pistons in the new block. The cam is the real question mark for me. I can't find any good conclusive info. I'll just have to make some phone calls to Delta, Bisi, Colt and some other places to pick some brains.
 

·
Registered
Joined
·
295 Posts
Discussion Starter #11
yeah i'm well aware i could mill the head, but in any of my scenario's it's not necessary, the compression is easily attained by the block/head/piston setup. I'm more than likely going to stick with the straight mini me setup and the supercharger but the ZC piston setups intrigued me, but i'm not getting much feedback.
 

·
Registered
EJ6
Joined
·
219 Posts
Yeah my initial though was maybe vtec would help with a little more power up top, power kinda dies off over 6k. But i am a fan of the A6, one of my favorite motors ever built. I was thinking about trying both heads (with the ZC piston setup) out but i can't afford to get both setups tuned. At least with the A6 block, Z6 head setup i could try that now and see if i like it. If it falls short of my expectations i can always do the ZC pistons in the new block. The cam is the real question mark for me. I can't find any good conclusive info. I'll just have to make some phone calls to Delta, Bisi, Colt and some other places to pick some brains.
I've done some looking into this too. The general consensus from what I've read is that a blower needs higher lift, greater lobe separation (less overlap) and little more duration on the exhaust side.

However, what I also learned is that there is no reference point to use this information. Most of these tidbits about blowers come from the V8 realm. The general concept is sound but the actual specific cam specs that are appropriate for our Honda's remain a mystery. Combine this with how small stock D16 camshafts are and it seems that ANYTHING would be better. It also seems that EVERYTHING could be worse.

Despite this, I'm going the path of a camshaft for my setup. I think there is quite a bit of power to be uncorked. I've talked to all the above companies and I've pretty much decided on a cam from Colt Cams. The underlying concept/technology that they apply to their cams seems that it would be perfect for a blower.
 

·
Brokedick Millionaire
Joined
·
40,267 Posts
I would keep the boost STOCK on the SC, just freshen it up, then run as much compression as you can afford with your rod and piston choice.

Seek of DIYsil Dave on here. He knows a little about high compression and boost :)

And what melts first :(
 

·
Registered
Joined
·
295 Posts
Discussion Starter #14
Ahhh exactly some of the guys i was waiting to chime in. Excellent info Arcane, i also was very interested in Colt cams, especially that Tri flow technology. Are they incorporating that into your cam?
Hey Transzex, what's that guys user name, that didn't come up when i did a search. I'd like to read some of his stuff. Thanks again both of you. Now i just need a few more of the educated regulars to chime in.
 

·
Registered
EJ6
Joined
·
219 Posts
Ahhh exactly some of the guys i was waiting to chime in. Excellent info Arcane, i also was very interested in Colt cams, especially that Tri flow technology. Are they incorporating that into your cam?
Hey Transzex, what's that guys user name, that didn't come up when i did a search. I'd like to read some of his stuff. Thanks again both of you. Now i just need a few more of the educated regulars to chime in.
Yes my cam will include Tri-Flow technology. It was one of the biggest selling points for myself. I just haven't decided on how big the cam will be because I've got to be emissions compliant where I am.
 

·
Registered
honda/firebird form.
Joined
·
6,966 Posts
and the hp looks like its still rising... i would rev it to 8k next time and see if it still makes power up there...
 

·
Meat Popsicle
91 CRX Si
Joined
·
2,936 Posts
Cam choice is one of the single most important things in a supercharged setup.

The D16A6/Y8/Z6 all make right around the same horsepower with the JRSC kit because the VTEC cams, while incorporating more lift, also have more duration which allows boost to leak right through the cylinders. The A6 cam works great because there's a small amount of overlap throughout the entire power band.

A6 heads are severely limited though because custom cams simply aren't an option. From what I've heard, the SOHC non-vtec cam blanks no longer produced so regrinds are the only option. These setups will benefit most from a mild regrind that only slightly increased overlap and provides a moderate lift increase.

There are far more choices when it comes to the VTEC cams because blanks are still produced but as far as I've seen, there's no off-the-shelf SOHC VTEC cam that's designed for a supercharged setup. If you have the funds, a custom profile would be ideal.

Bottom line, you need to minimize overlap and increase lift to make more power.

My opinion would be to stick with the stock VTEC cam unless you go custom...but that's just me.

Oh and the dyno graph above is a custom setup that uses a M62...not the M45 JRSC kit.
 
1 - 20 of 47 Posts
Top