Frogive me for this long post lol but I got some questions on pistons. I'm building a frank motor for a DD and was orginally going to use 87.25mm 09 TSX pistons (11.1cr). I'm limited to around 33-35 VTC with the OEM pistons. Lately I've been thinking about changing the pistons because I want to have pistons with deeper valve reliefs/compression. 89/91 octane unfortunately is what I have to work with.
Here is what my set-up consist of:
K24A1 block 87.25mm 09 TSX pistons (11.1cr) (if I decide to use these pistons)
Manley H-beam rods
OEM bearings, stock crank
4piston PRO 156 head, stock size valves, ferrea dish valves
RRC w/ 74mm HR TB (thinking of getting Stefan @ ASP to port my RRC, 400cfm)
RDX 410cc injectors
Drag Cartel 2.2 cams
ASP header, 3in exhaust
I know the OEM TSX pistons will hold me back but this is a true DD car, stop and go traffic etc. Reliabilty > a few more HP. Then again I want to utilize my set-up so I was thinking of switching to these pistons:
87.5mm Wiseco 11.1cr (2618 alloy)
87.5mm Arias 12.1cr (dk the alloy, waiting for them to email me back)
87.5mm CP 11.5cr.
I know the cams will reduce the compression as well as the cylinder head so I was thinking that I could utilize higher compression pistons because of this. The clyinder head will reduce compression because most pistons are made for heads with 50cc and they are really 52-53cc. I talked to Luke awhile back about this but he is hard to get in contact with.
I'm scared to run 2618 alloy pistons on the street in a DD car but I've been told it's easily do-able and longetivity isn't a issue once clearances are in check. Some engine builders have told me to run .0025 with the wiseco's and then some say to run .0030-.0035.
Looking for some experienced opinions/dicussion. I'm probably over-thinking this :facepalm:
The highest I want to go is 12.1cr, Mahle unfortunately doesnt offer that. This will always be an all motor engine so no boost. I'v heard from experienced engine builers that the 2618 wiseco pistons can last a very long time in a DD car, once well maintained. It's just the piston slap I'm worried about.
wiseco's piston is great, i understand you're worried about piston slap that's why i threw you mahle's name.
I don't think many people mention having piston slap problems with the wiseco's. check into what the piston to wall clearance is on them at room temp and operating temp. Out of your choices i'd pick wiseco fyi.
The 12.5:1cr Mahle's? If only mahle made a 87.5MM 11.5cr piston.
Maybe I'll just get the wiseco's afterall. The piston slap and cylinder wear it what I'm most worried about. As you can see I'm very anal about stuff lol
Any thoughts on the 4p PRO 156 w/ 11.1cr or on the rest of the set-up? I'd love to use higher compression but the gas just doesnt permit it :deadhorse: I'd think with the longer stroke of the K24, this shouldnt be overkill at all.
My engine builder is gonna CC my head to find out the exact chamber volume then the choice of pistons will be decided upon. I'm leaning more towards a 4302 alloy piston though.
Depending on your budget and your time frame you could look into getting either a custom wiseco or supertech (mahle IIRC) piston, then you could pick your desired compression ratio and needed valve relief.
I would also recommend the DC 3.2 cams if you are going that route, when I talked to Jeremy he said the 2.2 is more of a k20 cam.
I am doing a very similiar build to yours and am going with custom wiseco pistons with 11.7:1 cr with enough valve relief for the DC 4 cams.
I just received my spare Z3 head last week, so it hasnt been ported yet but talking with 4piston it sounds like they can get 350 cfm or so out of it. 260-290 cfm is typical of a stock head IIRC. It just depends how far you want to go with it.
I am picking up a ported RBC IM from a buddy thats going with a s/c. The only thing extra i will do is open the inlet up to 70mm to match the outlet of the j37.
As far as valvetrain goes im gonna use supertechs stuff :shrug:
I'm hoping for around 270whp or so BUT I dont have a dyno in my area so I will never truly know:facepalm:. What about you?
After doing some research, I'm just thinking of leaving my RRC stock, just opening the inlet to fit a 74mm HR TB and port matching it to the head. I keep reminding myself this is just a street DD motor so I dont need to overdue it lol this should be enough fun for a while.
Yeah if you have the RRC IM I would just open the inlet as well, I am hoping for as close to 300 whp as possible but I would be happy with anything above 280.
I got my custom pistons for the sti a few years back from no limit Motorsports. They were 100mm Manley slugs with a custom comp ratio and I think I got h beams and pistons for right at 800$ call them n see if they can best your price. 660$ for a smaller piston doesn't seem right!
If you stick to Big name gas like Chevron you really shouldn't have a problem with bad gas, they aren't like those fly by night cash only has stations. I'm running 12.5:1 compression on 91 pump from Chevron.
Those flat faces really won't do much for you at the end of the day, the money is better spent else where.
I dd on Shell 93 with 12.5:1 comp. I knock every once in a while but 99% of the time it's smooth sailing. It's really not a problem to run 12.5:1 on pump, as long as you don't have a habit of accidentally putting regular in or something
Still deciding on the TSX pistons or the wiseco's. Will the deeper valve reliefs really benefit me even though I'm staying with the same compression? From what I've gathered, the cams stop making power past 37 or 38 VTC so if I'm limited to 33* VTC with the stock pistons but can run 37* VTC with the wiseco's, how much of a power difference is that?
Never thought a decision would be so hard :deadhorse:
Mahle does have 12:1 pistons for k24, they have 4cc domes.
I havent done much with the drag cartel 2.2's but I would say you'd be giving up significant power in the midrange by missing out on that much cam angle.
If you need more info on the Mahle pistons just lmk
Any proof of this? With a K24, I dont think midrange would be a problem with the amount of torque they have correct?
Here's a dumb question:wigglesmiley: Say if I get a bad tank of gas, say 89 octane or something and I have the wiseco pistons, how would this affect it? Even if it's only 11.1cr.
you'll be fine. The reason it makes a difference on 12.5:1 is because you are already pushing the limits of pump gas, so anything less than quality pump gas and you start seeing issues.
What do you guys think about getting my RRC ported by Stefan @ ASP? This car will be a DD so the use of a center feed manifold isnt really in my thoughts to be honest.
Anyone seen results from porting one? It'll have a 74mm HR TB
If anything you could just port match the opening to match your TB. IMO your money would be better spent somewhere else than getting the full IM ported :shrug: I think the gains would be marginal on your setup.
Search ported RRC. There's quite a few threads on it.
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
8th Generation Honda Civic Forum
12M posts
157.4K members
Since 2005
We’re a community for 8th Gen 2006 - 2011 Civic owners to discuss performance mods, body kits, Si models, turbo kits and accessories. Come Join the club!