Choosing pistons. Please help.

[packinkimber45]

So I got my block from the machine shop they informed me that my piston to wall clearance is .0035. To do things right I am going to bore .020 over. As far as choosing the pistons, it's getting a bit confusing. Dealing with expansions, compression ratios, boost levels and such.

What are the advantages over the different brands? My hp level initially is 350-400 whp. Later down the road I would like to have more, that is why I would like to do forged pistons now so I am set up for later. After getting the car running I will be running 10psi for a while until I have enough funds to get all the supporting mods to run more. I currently have an evo3 16g. Car will be daily driven. I will be going with dsmlink as well down the road. I would like to run 20-25psi daily. I will be on pump gas initially, have not really looked into other alternatives. Not sure what I will want later, but I want to set myself up long term.

About compression ratios, I have read to stay as close to 7.8:1 as much as possible for easier tuning. Will 8.5:1 be that much more harder to tune and more prone to knock than lets say 8.3:1?

Also piston slap... which piston is more ideal for a daily driver where I wont have to worry about piston slap? Along with with performance, durability and reliability is a much since this is my daily driver. I really dont plan on taking my motor apart again soon after this build. Looking for pistons that does not require me to freshen up every year.

I think I have narrowed it down to Mahle and Wiseco for pistons. Either eagle h beams or manley h beams for rods. Comments, tips, advice on this set up or other set ups would be great. Also pros and cons with this set up and other set ups as well. Thanks.

 

[2slow4utsi]

For your hp goals you can run 1g rods if you want and as for pistons a lot of people run Wisecos but I like Ross or Mahle. I just recently purchased Ross pistons...they're sick.

 

[DSMer541]

i got Wossner pistons, 8:1 compression, and they are very close to an HD piston....i got them from MAPerformance....i wanted to stay as close to stock 6bolt compression for a good street tune and be able to run more boost on pump gas at the track, and its a DD .. I havent had any piston slap issues either, i set the ring gaps at the specified number, i compression tested it after about 700 miles and it was about 170-175 on all cylinders. call MAP and they will tell you all about them, great pistons , i like em!

i had the same goal you did..i wanted to build the bottom to be close to stock since i was only using pump gas and no dsmlink to tune yet, but still be able to make alot of power later down the road when i was ready to...

ps. im also using eagle H-beem rods and clevite77 bearings

 

[BoostedBeaver]

Everything I am about to mention is from reading articles on this site. I have no first hand experience with these parts as my build is in the makings as well. From what I have read Mahle or Ross pistons would be great choices in my op. I have read a lot of articles on the top ring land of the Weisco pistons cracking. This caused no performance loss but was found when the owners where refreshing there motors. The HD version of the Weisco is suppose to fix this issue but I have no prof. On the rods just depends what I could catch on sale. These rods will be able to handle your 400 and plenty more so the rods I would not worry to much about. Just choose a brand of your liking. Hope this helped and if any info is incorrect, Please feel free to correct me.

 

[dsmtbopwr]

For your goals I would suggest Mahle pistons. I am actually running them currently with 1g rods. My goal is 400whp.

 

[9!'clipseDOHC]

I'm running Wiseco 8.3:1 pistons on 6 bolt rods with ARP bolts and ACL race bearings. Should be good for over 500 hp which is well above my goals.

8.3:1 and 8.5:1 shouldn't make much of a difference with tuning. I can see your tune being more demanding with a 9:1 compression ratio.

 

[nkosi]

i got Wossner pistons, 8:1 compression, and they are very close to an HD piston....i got them from MAPerformance....i wanted to stay as close to stock 6bolt compression for a good street tune and be able to run more boost on pump gas at the track, and its a DD .. I havent had any piston slap issues either, i set the ring gaps at the specified number, i compression tested it after about 700 miles and it was about 170-175 on all cylinders. call MAP and they will tell you all about them, great pistons , i like em!

i had the same goal you did..i wanted to build the bottom to be close to stock since i was only using pump gas and no dsmlink to tune yet, but still be able to make alot of power later down the road when i was ready to...

ps. im also using eagle H-beem rods and clevite77 bearings

I just read up on the wossner pistons and i think im going to use them in my build this summer ...MAP are reputable guys and they explain the design of these pistond being "HD" and the compresion ratio close is to stock for daily driver ...thank u DSMer541 for puting up on these pistons ...i was going to go with mahle or Ross but these are much nicer for not much more money . Im going to use either K1 technologies light weight rods or Manley H Beam ...hopefully they can stand up to my goal of 650whp as for bearing i will also use the clevite77 ...good luck on your build man happy boosting

 

[VTEC KILLR]

I got a set of Evo9 pistons installed on my 1g rods. Ive only had this set up for about 400miles, but i like it so far. Cheap/strong/highly recomended.

 

[Colt4G63 also]

I use 9:1 CP pistons on Eagle H rods. The CP pistons cost a little more, but they're lighter, and don't tend to make noises. I also beat the snot out of my car daily for the last couple summers, and run 19 Psi on an E316G with 93 octane pump gas. It still works fine.

 

[packinkimber45]

Wow! Lots of info, thanks. I keep debating on going full forged on pistons and rods. I have about $1500 to spend, that's including any other work as far as machining and such. I also am debating if I should just go with 2g/1g combo as well.

VTec killr... how do you like your evo 9 on the big rods? How much boost are you running and what turbo? Also how did you install the pistons, did you reverse them or install them pointing towards the timing side?

9!'clipsedohc... how do you like that combo you have? I actually just saw on dsmgraveyard a set of new wiseco 8.3:1 with rings already hung on 1g rods that are reconditioned, balanced, and arp'ed for $500. That is off course with me sending in my 1g rods as a core. I am really considering this route since it is cheaper than all new forged pistons and rods. I know the rods at this point would be the weak link since the pistons are forged, but I am definitely thinking about it. Also how much boost are you running on what turbo?

 

[VTEC KILLR]

I am still breaking in my engine so the most I've seen right now is 16psi on my small 16g. But my small 16g just took a dump........again. I will be upgrading to a larger turbo soon. I downloaded a machine spec sheet from dsmgraveyard and gave it to my machinist and he took it from there. I believe the arrows were going toward the timing side....... But don't take that as gospel. My memory sucks. Dsmgraveyard can help you out alot. I didn't get my pistons from them (they were alittle high) I got mine used from eBay for 50 bucks with 15k miles on them. No piston slap, the 8.8 compression is nice.

You definately want evo9 pistons though ( they are coated and aluminum)
goodluck.

 

[9!'clipseDOHC]

9!'clipsedohc... how do you like that combo you have? I actually just saw on dsmgraveyard a set of new wiseco 8.3:1 with rings already hung on 1g rods that are reconditioned, balanced, and arp'ed for $500. That is off course with me sending in my 1g rods as a core. I am really considering this route since it is cheaper than all new forged pistons and rods. I know the rods at this point would be the weak link since the pistons are forged, but I am definitely thinking about it. Also how much boost are you running on what turbo?

I haven't had any problems with it but I'm still breaking my motor in with a 14b. I've been 930 miles so far, never over 4k rpms or 12 lbs of boost. I'm babying it crazy right not. $500 isn't that great of a deal. I got my pistons brand new from a supporting vender for $420 shipped and it was $60 or $80 to have them mounted on my 6 bolt rods. $500 for a used set up... While I haven't given mine any abuse, it is a proven setup and I'm sure it will work great for me.

Hope this helps!

 

[packinkimber45]

I haven't had any problems with it but I'm still breaking my motor in with a 14b. I've been 930 miles so far, never over 4k rpms or 12 lbs of boost. I'm babying it crazy right not. $500 isn't that great of a deal. I got my pistons brand new from a supporting vender for $420 shipped and it was $60 or $80 to have them mounted on my 6 bolt rods. $500 for a used set up... While I haven't given mine any abuse, it is a proven setup and I'm sure it will work great for me.

Hope this helps!

Wow that's a good price for the machining on the rods. Got a quote from a few machine shops locally and they want to charge me up to $200 for making the rods work for 22mm wrist pins. The set I saw on dsmgraveyard are actually for a new set of wisecos not old ones. The rods are already hung on the pistons, also reconditioned, balanced, and arp rod bolts installed from the vendor. I'm really leaning towards this set up but other than you I havent seen any other experiences with forged pistons on stock 1g rods.

 

[lucuc0212]

I'm in the same boat as your right now. I'm doing a motor build starting with the bottom end and looking for the best piston/rod combo I can find to hold the power and have the least amount of load/stress. Thinking of going with Oliver alum. Rods and Mahle pistons cause from as far as I've read seems to be the lightest and very strong well capable of holding 600-750hp which is my goal. I don't know how far you plan to rev to, but from the research I've done the weight of rod/piston plays a big part of it all. HD pistons are good for big power, but weigh much more than normal and will cause a lot of load. If your planing on going bigger cam which seems to be a must you want to rev higher than 6500rpm (which is all you stock cams will make power up to I know the rev limiter is 7500rpm) than all this will come into play. I'm by far no expert so anyone correct me if I'm wrong I've been doing research on the same thing rod/piston set ups with just a bigger hp goal for awhile now so let me know also if I'm going in the wrong direction just like everyone else I want to learn from others who have been down this road and do it right the first time.

 

[AliceCooper]

Your setup looks good! I am currently picking out parts for my bottom end also. Im going with Mahle pistons with 8.5:1 comp ratio and Eagle H beam rods. But I have a question. How streetable will these internals be? This is my DD so I was wondering if I will have any problems with piston slap or anything with this setup. Going with Clevite main and rod bearings also.

 

[packinkimber45]

Your setup looks good! I am currently picking out parts for my bottom end also. Im going with Mahle pistons with 8.5:1 comp ratio and Eagle H beam rods. But I have a question. How streetable will these internals be? This is my DD so I was wondering if I will have any problems with piston slap or anything with this setup. Going with Clevite main and rod bearings also.

I'm sorry but I dont have first hand experience in order to answer your questions. From my research and from speaking to certain people the Mahle pistons, require less pistons to wall clearance. The way they are made they expand less than other pistons manufacturers out there. This is why I have decided after all this time researching about pistons to go with Mahle.

I ordered a set of .020 over Mahle pistons, Manley H beam rods, and dsmlink V3 (to fix any knock issues I might come across due to the difference in compression ratio from the stock compression and for tuning in the future as well.). My parts should get here next week.

 

[slowgsr]

cp pistons, 4 thous p2w, 9:1. can't go wrong. I would keep compression at 9:1 or so, tuning isn't a big deal. I wish I would have gone with the cp's over my wiesco's, however.. I have very little noise/slap with my wiesco's with 4 thous p2w. Im just going to push them anyways,

proper machining/assembly is the most important part of building an engine.

under 500hp you are fine with stock internals. Obviousy a high comp engine will be more efficent and make power better, but stock engines can be pushed to 500 with proper tuning.

 

[Heartless]

As much as I'd just like to say for your power goal just go with Evo9 or 2G pistons on stock rods, but I know better. You always over build an engine for whatever application your yousing it in because your either going to want more boost or just for the sake of an extra piece of mind that a rod wont go throught the block (well hopefully not, ). Granted those combos can support 500hp if you decide to go that far but for how long reliably? I've personally always went with forged pistons and rods in my engine and my friend's engines. I personally run Ross (has a larger piston to wall clearance) and Eagle H-Beam rods, I prefer the better metal used (debatable, I know) and have never had an issue with piston slap. You should always let your engine warm up some before taking off and warm up before beating on it anyways so you should never have to worry about piston slap. Weisco, Ross, JE, and Mahle are all great pistons and never given me any problems with any engine I've put them in. In the end you'll be happy with the Evo9 or 2G piston combos if you want to go that route but forged is always extra insurance As far as rods the Manleys and Eagles aren't need at that power level but a good idea if you wanna go for more boost They're both basically the same, Eagle says their highest reported back hp on theit H-Beams is 900 and some odd hp!