Upgrade Ideas...Food For Thought.

[wcmbrk]

I'm running a normal 24a1 head on a3 block, I did upgrade the valves to the dished 0.05 mm if that helps...I'm running the 8 exh rocker setup...with z1 cams...I guess I'm just looking for which would get me better results as the price would be the same....
option 1: my a2 block...get it installed with 11.5 pistons/rods with my 24a1 head...tuned
option 2: a3 block/24 head, but purchase some cartel DIC cams and upgrade tensioner and tune...
I feel both options are about the same price...1200-2000k with installs...I'm aiming for 230-240...
food for thoughts

-Robb

[Powers]

A2 block for sure man. That would be a pretty sweet setup.

[USAF EP3]

Just so you can put this into perspective a tad bit better:

An 06-08 K24A2 with factory compression (10.5:1) at full tilt and bolt-ons tuned for high RPM power will put out just shy of 230whp, more likely 220-225.

If you were to use 11.5 compression pistons you will be well above the 250whp marker.

[lemonhead228]

I would do k24a2 block with k20a2 head. Keep k24a2 cams. With I/rbc/rh/3"e you hit 240 whp with ease but the tune is key! Drop a set of cams you be 250+whp

[wcmbrk]

I would do k24a2 block with k20a2 head. Keep k24a2 cams. With I/rbc/rh/3"e you hit 240 whp with ease but the tune is key! Drop a set of cams you be 250+whp

i have a a2 block just sitting in my garage though heh

[lemonhead228]

i have a a2 block just sitting in my garage though heh

K20a2 block? I would be kinda hard to hit 240 with the a3 since it cant rev as high. If you use the a2 block a1 head with some cams you be around 230-240 whp. With bolt-ons

Or since you going 11.5 comp you can slap it in the a3 with some decent rods and oil pump and be just as good.

[wcmbrk]

Yea that's what im thinking...cp pistons/crower maxi lite rods and new bearings etc...slap the the a1 head..and go...hoping for the 230-250


K20a2 block? I would be kinda hard to hit 240 with the a3 since it cant rev as high. If you use the a2 block a1 head with some cams you be around 230-240 whp. With bolt-ons

Or since you going 11.5 comp you can slap it in the a3 with some decent rods and oil pump and be just as good.

[Ba82Ep3]

K20a2 block? I would be kinda hard to hit 240 with the a3 since it cant rev as high. If you use the a2 block a1 head with some cams you be around 230-240 whp. With bolt-ons

Or since you going 11.5 comp you can slap it in the a3 with some decent rods and oil pump and be just as good.

^^^ this

The k20a3 block is the same as the k20a2... just the a2 is drilled and tapped with the oil squirters. The squirter bosses are present in the a3 block.

If you already have a k20a2 block... i would take it apart... order up some OEM 11.5 (RRC) slugs and balance them with the OEM rods and crank. Use the k24a1 head VTEC killed on DC's DI cams. You need the higher compression to make the most out of your cam purchase, and OEM slugs will give you long life with daily driven abuse. Go for a k20z3 oil pump, as it will help balance the setup, provide proper oil pressure, and set the rev limiter to 8800 RPM and tune it.

If you have the supporting TB/intake and RH/exhaust... i could street tune it and hit 240/161 easy. You could prolly find more TQ on the dyno, as you can fine tune ignition advance without guess work.

Me personally... i still want a modded S2K crank for a 2.2 build. Its the custom rods and pistons that hold me back...

[wcmbrk]

^^^ this

The k20a3 block is the same as the k20a2... just the a2 is drilled and tapped with the oil squirters. The squirter bosses are present in the a3 block.

If you already have a k20a2 block... i would take it apart... order up some OEM 11.5 (RRC) slugs and balance them with the OEM rods and crank. Use the k24a1 head VTEC killed on DC's DI cams. You need the higher compression to make the most out of your cam purchase, and OEM slugs will give you long life with daily driven abuse. Go for a k20z3 oil pump, as it will help balance the setup, provide proper oil pressure, and set the rev limiter to 8800 RPM and tune it.

If you have the supporting TB/intake and RH/exhaust... i could street tune it and hit 240/161 easy. You could prolly find more TQ on the dyno, as you can fine tune ignition advance without guess work.

Me personally... i still want a modded S2K crank for a 2.2 build. Its the custom rods and pistons that hold me back...

I think you just gave me an awesome road map...btw...my block already has the oil pump...would that suffice?

[Ba82Ep3]

Already has a k20z3 oil pump? Its a balance shaft pump, unlike the k20a2 oil pump...

[wcmbrk]

No it has the standard a2...hmmm how much does the z3 go for? Hmm i've been looking up the rrc pistons...can't seem to find a place to buy them...also someone put that you should get a mm over to set the piston...is that true? Thanks for all your help.

[Ba82Ep3]

You see z3 pumps used for $200+ As much as i hate the idea of buying a used oil pump... the cost of a new z3 pump is worth the search for a 'gently used' one. I myself use the a2 pump, have for years with no problems... but long to smooth things out with the z3 pump. The higher you rev the more it matters for long term reliability. k20aR engines got along just fine without the z3 pump... but its just icing on the cake.

HMotorsonline.com sells RRC slugs... but only in the A size. Seems they are harder to find now. You need to check and see what you have in your block now (A or B size). Pull a piston, look for the stamp and measure it across the width of the skirts, just above center wristpin height. Lemme know whatcha got.

Yes it is best to start with a fresh bore and a larger piston, but it is not always necessary. Tolerances dont lie though, and if you have an A bore in good shape with visible OE crosshatching... you can use a new A slug and rings with no issue.

There has been debate on the actual cr rating. The PRC slugs are stated as 11.5 and the RRC slugs are 11.7. Both seem harder to find now in the larger size. #j/edmstruggle

Saw a link on k20a.org, someone asking for RRC pistons. Bodyman from AFH suggested PMing Tegiwa. Ill spend some more time looking tomorrow to see what i come across. Its after 2am now...

[Ba82Ep3]

I lied... i kept looking. LOL

https://www.tegiwaimports.com/index.php/select-car/honda/fd/engine-parts-oe/genuine-honda-civic-type-r-fd2-k20a-rrc-piston-set.html

[wcmbrk]

you are the man!!! hmm now I need our dollars to go up against the pd...lol

[wcmbrk]

You see z3 pumps used for $200+ As much as i hate the idea of buying a used oil pump... the cost of a new z3 pump is worth the search for a 'gently used' one. I myself use the a2 pump, have for years with no problems... but long to smooth things out with the z3 pump. The higher you rev the more it matters for long term reliability. k20aR engines got along just fine without the z3 pump... but its just icing on the cake.

HMotorsonline.com sells RRC slugs... but only in the A size. Seems they are harder to find now. You need to check and see what you have in your block now (A or B size). Pull a piston, look for the stamp and measure it across the width of the skirts, just above center wristpin height. Lemme know whatcha got.

Yes it is best to start with a fresh bore and a larger piston, but it is not always necessary. Tolerances dont lie though, and if you have an A bore in good shape with visible OE crosshatching... you can use a new A slug and rings with no issue.

There has been debate on the actual cr rating. The PRC slugs are stated as 11.5 and the RRC slugs are 11.7. Both seem harder to find now in the larger size. #j/edmstruggle

Saw a link on k20a.org, someone asking for RRC pistons. Bodyman from AFH suggested PMing Tegiwa. Ill spend some more time looking tomorrow to see what i come across. Its after 2am now...

Ok so took a look and on the middle of the piston is the stamp B...

[Ba82Ep3]

Ok... thats a good thing... larger OE slug... but finding J/Edm slugs in B is different. Mahle may be your route if none are found. Ill dig around a little more and see what i come across. Either way you dont wanna go below 11.5cr with your cam choice.

[Ba82Ep3]

Some of Chunkys research info pertinent here:

"For my last motor build, I did some investegating on this myself. I took an OEM piston, my CP 2618 alloy pistons, and supertech 4032 alloy pistons and measured them cold & hot. I was impressed with how little the stock piston expanded, but more importantly how ROUND the stock piston was.

OEM pistons are the best pistons to run, unless you're building a motor that will exceed the strength parameters of the stock pistons due to heat or revs. If you are forced to switch to forged, I always recommend 4032 before 2618 because you can run a tighter piston to wall clearance with a 4032 piston.

For my next build, I'm using Mahle 86.5mm 12.5:1 compression pistons. I called up Mahle and asked them what kind of piston to wall to run for an n/a motor revving to 10k with a potential 100shot of nitrous. He said that I would be fine at the tigher end of their spec sheet, which is 0.0025". That seems fine to me as the supertech pistons from my last build came out looking great at a 0.0028" piston to wall. With a thermal barrier coating on the piston tops, I could potentially push that clearance even tighter than the 0.0025" on the sheet. The only way to really know would be to measure the thermal expansion of the sleeves. I have a trashed block from which I could cut a cylinder out in order to measure the OEM sleeve expansion rate. I've got a plasma cutter on order, so expect to see this happen sooner rather than later. The goal is to figure out exactly how tight I can push my installed clearance with the mahle pistons on stock sleeves.

If you want to build something that's between a pure street car and race car, which is what most of us here are doing, 4032 is the way to go. It gets you as close to OEM start-up-and-go as possible with a forged piston, and gives you the ability to push the motor farther in terms of revs & heat."

[Ba82Ep3]

http://www.inlinefour.com/jdmhonoempis.html

Looks promising for a std B size...

[Ba82Ep3]

Or for just a touch more (with rings), knowing what you read above, you could go this route...

http://www.jhpusa.com/store/pc/viewPrd.asp?idproduct=3010&idcategory=1619

You can even get 86.5mm. That way you could have the block bored if need be (dunno the condition of the sleeves).

That with a balanced OEM crank/rod setup... :mtongue:

You could go higher on compression but you run into valve relief considerations with your cam choice. If i chose the Supertech slugs, i would use the 11.9cr with flat faced valves. Should put you right at 12cr which can be run on 91 or 93 octane.

[wcmbrk]

Hmm i have to check what kind of valves i'm running i know i'm running supertech valves nitride coated in my head...thanks so much for the feedback...!

[wcmbrk]

would the a2 pistons work with the 24a1 head with out any issues...i might just use the block and standard a2 pistons if they would work correctly.

[Ba82Ep3]

Yep... thats my setup. k20a2 slugs and k24a1 head.

[wcmbrk]

what compression are you getting out of your setup...have you dynoed yet bro?

[Ba82Ep3]

Im using a k24a1 head gasket, so my static compression should be right at 10.99:1. Im still using the k20a3 crank and rods, so my max RPM is 7700 (again the goal was to maximize the build for the supercharger at a given rpm).

Ive dynoed several times at varying stages of the build. The last time i dynoed i removed the OEM stock 95 Civic exhaust and added 2.5 mandrel bent in its place as the only parts change. After street tuning i picked up 30whp/15wtq. All dyno runs were on the same dyno at TDC here in Mobile. Its not fair to compare (to what you may have) because i was still using an OEM Accord header. But if you take that into account, what i dynoed was impressive and raised many eyebrows. lol

So if you ask me what i will make by adding my KTuned race header? All else being the same? 215whp/160wtq@7700rpm (which is close to what the average k20z3 makes at 8600rpm with I/RH/E/FlashPro). Once my car is back on the road i will be doing another dyno run with the header as the only change to know for sure.

Trust me... im considering some higher cr slugs since the car is down, but my comparisons on the dyno would change. Id really like to make as much power as possible on low boost... even 7500rpm if i could. I wanna be sure i dont stress the a3 rods with ignition advance AND boost. You however... you have a stronger bottom end so that isnt a concern of yours.

I guess i need to clarify that the SC hasnt been installed yet. Reading through, it would be easy to mistake that. My build has been developed to take advantage of the SC...and to help ME better learn the nuances of the setup (mini VTEC) and how it makes power. Adding the SC will be the last stage, and IMO ill be better able to street tune it after knowing how the engine handles air throughout the rev range at given cam angles.

[wcmbrk]

Im using a k24a1 head gasket, so my static compression should be right at 10.99:1. Im still using the k20a3 crank and rods, so my max RPM is 7700 (again the goal was to maximize the build for the supercharger at a given rpm).

Ive dynoed several times at varying stages of the build. The last time i dynoed i removed the OEM stock 95 Civic exhaust and added 2.5 mandrel bent in its place as the only parts change. After street tuning i picked up 30whp/15wtq. All dyno runs were on the same dyno at TDC here in Mobile. Its not fair to compare (to what you may have) because i was still using an OEM Accord header. But if you take that into account, what i dynoed was impressive and raised many eyebrows. lol

So if you ask me what i will make by adding my KTuned race header? All else being the same? 215whp/160wtq@7700rpm (which is close to what the average k20z3 makes at 8600rpm with I/RH/E/FlashPro). Once my car is back on the road i will be doing another dyno run with the header as the only change to know for sure.

Trust me... im considering some higher cr slugs since the car is down, but my comparisons on the dyno would change. Id really like to make as much power as possible on low boost... even 7500rpm if i could. I wanna be sure i dont stress the a3 rods with ignition advance AND boost. You however... you have a stronger bottom end so that isnt a concern of yours.

I guess i need to clarify that the SC hasnt been installed yet. Reading through, it would be easy to mistake that. My build has been developed to take advantage of the SC...and to help ME better learn the nuances of the setup (mini VTEC) and how it makes power. Adding the SC will be the last stage, and IMO ill be better able to street tune it after knowing how the engine handles air throughout the rev range at given cam angles.

Sounds like an awesome setup...so if i read it right you are using a2 pistons with the a3 connect rods/crank. I didn't know they all fit. I'm probably asking a lot of noob questions because you are one of the few people with something similar to mine...and i'm a noob so all your help is greatly appreciated. Currently, i just got the block taken apart...bbbb slugs are bigger? I think i'm going to just order 86.5 mm slugs and call it a day to make sure the piston to wall contact is good. Thanks again for the help! i made a lot less than you...using a3 slugs i dynoed 192/153...but the great thing was the peak hp went from 5800-redline...so it keeps me in powerband the whole time. I look forward to more share of your build and as well as ur input for me.

[Ba82Ep3]

Yeah the a3 crank and rods have to go together. a3 rod journals are smaller than a2 rod journals... so rods and crank have to stay in the family. As far as OEM slugs go... A size is smaller than B. An A sized slug will look like tossin a hot dog down a hallway in a B sized sleeve. lol Yeah... not that bad but it will be obvious.

Pistons interchange though, as the wristpin is the same size (as is the general rod to piston area design and combustion height... or wristpin center to top of the piston minus dome changes).

86.5 would be a good idea if you arent sure of cylinder wall condition. Just remember to get over sized rings, and gap them according to your RPM goals. The tolerance for them is in the manual. As a general rule for NA, less gap for lower RPM, more gap for higher RPM. That is not to say gap them at the widest tolerance for 8600 RPM. You could end up with an oil eater 30k miles later.

And there are no noob questions. Everyone notices different things. Thats why we share our findings here on the web. :mcool:

[USAF EP3]

Sounds like an awesome setup...so if i read it right you are using a2 pistons with the a3 connect rods/crank. I didn't know they all fit. I'm probably asking a lot of noob questions because you are one of the few people with something similar to mine...and i'm a noob so all your help is greatly appreciated. Currently, i just got the block taken apart...bbbb slugs are bigger? I think i'm going to just order 86.5 mm slugs and call it a day to make sure the piston to wall contact is good. Thanks again for the help! i made a lot less than you...using a3 slugs i dynoed 192/153...but the great thing was the peak hp went from 5800-redline...so it keeps me in powerband the whole time. I look forward to more share of your build and as well as ur input for me.

You don't need to order 86.5mm if you don't feel comfortable with getting the pistons mixed up. Do what I did and have the block bored out to Honda std. oversize which is 86.25mm for the K20 engines. With 86.5mm you will have to use an aftermarket company.



Yeah the a3 crank and rods have to go together. a3 rod journals are smaller than a2 rod journals... so rods and crank have to stay in the family. As far as OEM slugs go... A size is smaller than B. An A sized slug will look like tossin a hot dog down a hallway in a B sized sleeve. lol Yeah... not that bad but it will be obvious.

Pistons interchange though, as the wristpin is the same size (as is the general rod to piston area design and combustion height... or wristpin center to top of the piston minus dome changes).

86.5 would be a good idea if you arent sure of cylinder wall condition. Just remember to get over sized rings, and gap them according to your RPM goals. The tolerance for them is in the manual. As a general rule for NA, less gap for lower RPM, more gap for higher RPM. That is not to say gap them at the widest tolerance for 8600 RPM. You could end up with an oil eater 30k miles later.

And there are no noob questions. Everyone notices different things. Thats why we share our findings here on the web. :mcool:

I had mine gapped a cunt-hair looser because of boost and RPM right now, and I will have to agree with the oil-eating line!

I use about 1 quart of oil every ~1200 miles of driving. My dry compression always comes out good though at 220-220-230-225 so I can't complain!

BTW, Dave you never call me! I need to get in touch with you soon. I'm at the point of just sending you tons of money through PayPal just to get your attention lol!

[Ba82Ep3]

Yeah Kev... boost gap can be different when compared to NA gap. The hotter the piston/bore, the more it expands. If you dont always run at that level, you can alter your tolerances to avoid eating oil.

You personally could probably afford to run a little leaner AFR between 3500 and 6500 part throttle boost (NOT WOT) and notice less oil consumption. Id have to look at your plugs and piston tops to make that call tho.

Bro... dont sweat the fone thing... im always busy as fawk and never have enough time in a day to do everything i need to do. : / I cant honestly say if i for sure have your fone number, so you need to send it to me again. Ive been through 3 in the last year and EPHatch has some stupid low amount set for PMs.

[USAF EP3]

Yeah Kev... boost gap can be different when compared to NA gap. The hotter the piston/bore, the more it expands. If you dont always run at that level, you can alter your tolerances to avoid eating oil.

You personally could probably afford to run a little leaner AFR between 3500 and 6500 part throttle boost (NOT WOT) and notice less oil consumption. Id have to look at your plugs and piston tops to make that call tho.

Bro... dont sweat the fone thing... im always busy as fawk and never have enough time in a day to do everything i need to do. : / I cant honestly say if i for sure have your fone number, so you need to send it to me again. Ive been through 3 in the last year and EPHatch has some stupid low amount set for PMs.

Sent you a text.

So, would that be a good suggestion if OP wants to stay with OEM parts? Not sure if he has decided to use aftermarket forged options. I'm personally biased to OEM Honda parts because they do so well considering what we put them through and only feel the need to use forged options if it really calls for it or it's a balls-out build.

[Ba82Ep3]

I always try to use OEM if i can. OEM oversized slugs (86.25mm) would work fine for him, but either way a shop will have to bore the block to match. Like you said though... if it was all out race (unless the rules stated otherwise) id have forged internals.

All Spoon has done for years is buy Honda OEM parts in bulk and balance/weight match them before any work is done to them... and THEN balance the build even more. Honda really gives us all we need for quick street cars...

If i had the $320 at the time i was puttin my engine together i would have scored some 86.5 RRC slugs. I instead scooped up 87mm k24z slugs a little later to install with the block rebuild (i have an in spec a2 crank but still need rods) on down the line. You know how it is... stacking parts for shit that aint gone wrong yet. LOL

[wcmbrk]

Sent you a text.

So, would that be a good suggestion if OP wants to stay with OEM parts? Not sure if he has decided to use aftermarket forged options. I'm personally biased to OEM Honda parts because they do so well considering what we put them through and only feel the need to use forged options if it really calls for it or it's a balls-out build.

I'm going to stick with OEM...just got the whole block disassembled...i went onto an Acura parts online store...i'm looking for BBBB pistons...i'm just not sure which to order...the oversized one? Or the regular...can anyone tell me in laymans terms what i need to tell the shop to do...sorry for again being a build noob...i agree with your assessment of stock slugs...I've been trying to find RRC slugs and autofair said they are no longer sold...is HMOTORSONLINE still legit? Thanks so much for the help...also damn...i caved in and bought a vtec a2 head...so i guess i'm going to sell the k24a1 head...but damn it was such a good setup...keep the help coming...it's highly appreciated!

[wcmbrk]

Yeah the a3 crank and rods have to go together. a3 rod journals are smaller than a2 rod journals... so rods and crank have to stay in the family. As far as OEM slugs go... A size is smaller than B. An A sized slug will look like tossin a hot dog down a hallway in a B sized sleeve. lol Yeah... not that bad but it will be obvious.

Pistons interchange though, as the wristpin is the same size (as is the general rod to piston area design and combustion height... or wristpin center to top of the piston minus dome changes).

86.5 would be a good idea if you arent sure of cylinder wall condition. Just remember to get over sized rings, and gap them according to your RPM goals. The tolerance for them is in the manual. As a general rule for NA, less gap for lower RPM, more gap for higher RPM. That is not to say gap them at the widest tolerance for 8600 RPM. You could end up with an oil eater 30k miles later.

And there are no noob questions. Everyone notices different things. Thats why we share our findings here on the web. :mcool:

HAHAHA like a hotdog down a hallway....haven't heard that in ages.

[Ba82Ep3]

You need over sized slugs and rings. Sorry i havent been on its been really busy on my end. Text me if need be. Just let me know who you are in the text. I dont respond to calls i dont know lol

251-533-8384

- Dave

[wcmbrk]

Well found a place that can get the OEM slugs...i'm checking if they are PRC or RRC...they didn't specify...the damn things are 533 plus need piston rings...is that a good price?? Or should i just go with wiseco's...

[USAF EP3]

Well found a place that can get the OEM slugs...i'm checking if they are PRC or RRC...they didn't specify...the damn things are 533 plus need piston rings...is that a good price?? Or should i just go with wiseco's...

I would use Mahle. They offer forged pistons with two different types of alloy.

2618 alloy has less silicon and expands more:
tend to "piston chatter" when cold until the engine warms up, for cars that strictly race, less engine life, stronger piston for higher combustion chamber temps/pressures, more ring clearances (looser)

4032 alloy has more silicon and expands less:
less silicon than OEM cast pistons, forged process, same alloy as the pistons used in Honda S2000, less ring clearances (tighter), can be use as OEM replacement since they have great wear characteristics and are stronger than OEM cast.

[Ba82Ep3]

For 533 no rings...they better be OS RRC. Thats kinda high...then it isnt considering the ability to source.

If they are OS RRC slugs id do it and scoop k20a2 oversize rings and call it a day. Sure its a chunk but its the CR you want with OEM slug reliability.

Mahle are a good choice as well tho. lol

[wcmbrk]

For 533 no rings...they better be OS RRC. Thats kinda high...then it isnt considering the ability to source.

If they are OS RRC slugs id do it and scoop k20a2 oversize rings and call it a day. Sure its a chunk but its the CR you want with OEM slug reliability.

Mahle are a good choice as well tho. lol

Yea so the guy emailed me back that they are PRC slugs...I think they are the 11.5 cr...I will check the mahles...on a lighter note finally got my vtec head...I'm finally going to have real vtec...all in all I pieced together an a2 for 1000 (block 450, head 500)...now time to look into these Drag Cartel DIC's...thanks for the input fellas...it is definitely much appreciated...too bad you guys aren't in NorCal...I'd of already bought u a couple of beers...and maybe even hired you =)