View Full Version : st185 piston upgrade?

01-14-2011, 06:15 AM
hey everyone, ive got a USDM 185 swap in my 165. i was told that the pistons are the weakest point on the engine, and can only handle about 300horses. is this correct? if so, im planning to reach atleast 400 horses by the time summer ends, heres what i currently have. JDMsport FMIC,2.5" piping. HKS SSQV BOV, ebay 3" downpipe, 3" mid pipe, Ypipe to manual 3" dump valve, then back to stock exhaust for when i dont want to be obnoxiously loud. twos R us MBC set to 15pounds. and a K&N intake.

heres my dilemma, if the above information regarding the pistons only holding 300 horses is correct, then if im going to go past that, i need new pistons. (forged of course). whatre some good pistons? so far wiseco is the cheapest i know of. about 800 for some pistons and eagle rods. but then again i was also told the stock rods will be good to 550horses.

im just lookin on some advice for what should be done to get to my goal of a 400horse power street machine.:))

01-14-2011, 06:28 AM

01-14-2011, 06:31 AM
ah, forgot about that site...its been awhile since i read it. ill check it out.

01-14-2011, 06:32 AM
Oh and Mahle pistons are the best out there for longevity in a modified street engine that isn't crazy horsepower.

01-14-2011, 06:38 AM
how much would they run me?

01-14-2011, 06:47 AM
$550 I think check with http://www.importperformanceparts.net/ they had the best price back when they had a price listed(now you have to call in). And I reccomend these due to the low expansion rate vs. shit like JE's and CP's, they just aren't for the insane hp numbers but 400 is well within the range. Also if you do go with Mahle's make sure you go to a machine shop that knows what they are doing and are willing to do a correct piston to wall clearance not the generic forged piston clearance that lower silicon pistons use.

01-14-2011, 06:54 AM
What turbo will you be using. A CT26 will not get you there.

01-14-2011, 06:59 AM
ill definately check into them. 550 is a decent price. i was thinking more long the lines of 1000. but i can definately do 550:)

noooo! i will definately be upgrading from a ct26. possibly to a t3/t04z turbo. its about 800bucks. ive been told some good things about it.

01-14-2011, 07:06 AM
If you still wanna spend a grand you could get Pauter or Carrillo rods.

01-14-2011, 07:14 AM
if the stock rods are good till 550 horses ill pass. i dont plan on pushing those rods to the limit at all. this is just a DD weekend warrior...

importperformanceparts.net isnt working for some reason. even when i google it...wierd

01-14-2011, 07:39 AM
Yeah I was joking about the rods. The link I gave in post #6 ^ doesn't work? If not try flatlanderracing.com same store just the domestic big brother that was the first summit/jegs type store out there.

01-14-2011, 04:16 PM
Alright. Ill definately check it out.

But if I wanted to spend another 500bucks id rather get the ATS intake manifold. :)

01-14-2011, 04:34 PM
Stock pistons can handle 400whp, BUT, what they can't handle, is any sort of detonation at that power level. Anything in the slightest and they are going to be toast. Stock rods are quite strong, maybe 550 like you're estimating, but they are one of those things that "while it's apart" you might as well upgrade.

Wiseco, CP, Ross, Mahle, JE all make pretty good pistons. I'd sway towards the 8.5:1 versions instead of the 9.0:1's, just keep an eye out for what HG thickness those are rated at. I'd recommend giving one a company like ATS a call and they can definitely set you up.

I take it you are planning other mods such as turbo, fuel, and ECU as well?

01-14-2011, 04:43 PM
Yes sir. I am in the prestages of building my engine. Now that I've got the swap complete and its a DD, I want to internally build the block to handle a bigger turbo. And yes, a bigger turbo means a couple other upgrades. But as of now, I will be just preparing my block to handle the extra horses.

As for the rods, I'm on somewhat of a tight budget, I may or may not do them. And I definately see what you mean about replacing them since they will be right there during the piston job. But I do not plan on going over 500horses. So they will do me justice for now.

As for a head gasket, I know if I want to up the boost, I need to make a change over to a MHG. I know HKS makes some but HKS is also expensive. Any suggestions on a fairly priced MHG?

01-14-2011, 05:16 PM
Cometic. I think ATS has them for $160...I think it's cometic they carry anyway. Mine is TTE but that's no longer available from what I understand.

01-14-2011, 06:05 PM
Cometic is the MHG correct?

01-14-2011, 08:10 PM
You can get the Cometic head gasket for under $100. It is a MLS head gasket and will take all the power you will be throwing at it.

01-14-2011, 09:15 PM
Yeah I thought Cometic was inexpensive. Not sure what brand ATS carries, they still have the TTE image on their site. It is a good gasket.

01-15-2011, 07:08 PM
Yeah I thought Cometic was inexpensive. Not sure what brand ATS carries, they still have the TTE image on their site. It is a good gasket.

The ones ATS carries that are the most expensive are cut large for 5SGTE setups. 5S bore sizes with 3S water ports.

Edit: My bad chris, I just went to the site and saw they were the same price. IIRC ATS said they have them custom made similar to TTE construction. But meh, if you're going standard rebuild then just get cometic. If you're going 5S based then spend the coin on ATS' MLS headgasket. Or take your chances at buying an OEM 5S gasket (also MLS) but risk damaging it when modifying for the water jackets.

01-22-2011, 06:29 AM
Um... I've heard great things about Ross and their customer support. CP (makers of Carillo Rods) make great pistons and many great off the shelf options.