Ok well I have a question, if I could afford to get either pauter rods, or 8.5 pistons but not both with an APS TT install which one would you guys suggest? Stronger rods to handle the high effective compression or pistons to lower the effective compression ratio but with stock rods? Yes I know I could hold out a little more and get both done, but if I absolutely have to pick one over the other, which should it be? Thanks.

 

TomCatm

Get a signature loan - The real issue is if you are going to pull the engine down, Rod Bearings, Crank Bearing and Full Gasket kit.. Then it would be to your benifit to do both Rod's and Pistons.. Why Balance a partial kit..

Cheers Amy -

 

I agree . . . you'll save youself hundreds by installing both items at the same time (preferrably when you install the APS kit). By tearing down and rebuilding the engine on multiple occasions, you open yourself up to gasket replacements, increased labor changes, and unnecessary fluid changes. What's another two car payments for piece of mind and a complete job . . . ?

G

 

BTW, the complete gasket kit and associated bearings costs right around $400. So you really want to do rods and pistons together and at the same time.

--Steve

 

What fuel octane do you intend running and what is your power goal?

Peter

 

Hi Peter, I would be running 93 octane and my goal is only about what a stock aps kit will make with a true dual exhaust with the "out of the box" boost, which seems about 400 whp give or take(will be getting it done at SGP). I have read up enough on the forum to know that the stock engine will be okay with this output, but I just want to have the extra insurance of having some kind of forged part. Since i was only plan on keeping it at around 400 whp, I thought just going with low CR pistons would be enough and at the same time reduce the stress on the engine. But like I said its only if I absolutely find myself in a position where I have to do that, but hopefully I will be able to get both done at the same time. Sigh...thats atleast 4 months of paychecks.

 

all or none is the way to go -- if you're going to go forged bits at all, the amount of labor is prohibitive to do it one piece at a time (not to mention that it really wont help too much). You know the old saying "a chain is only as strong as its weakest link"? Well just doing the rods or just doing the pistons merely means that if your motor breaks it will just be a different part than usual.

That being said, supposedly the APS kit it built so that on stock boost it can be regulated / monitored to the point that you won't blow your engine on stock internals...

if you're dying for 400whp, then just get the TT kit, but you might want to start saving for a built engine (as this won't satisfy you for long)... if you're ever planning on going above that level, you'll want to have forged internals (all of them), and you'll want to do them all at one time.

i'm kind of in the same financial situation that you seem to be in, so I'm building the motor first and will pick up a TT later, so i'll just be running a forged NA block (albeit a very well balanced N/A with some headwork and lopey *** cams ). It just depends on what you want out of the car. But bottom line, opening up the engine to just replace one part is pretty stupid, IMHO. Basically, all or none

My £0.02

 

Agreed....you wil be fine at stock boost levels and around 400whp without changing internals. It would really be a waste of money to change rods only, or pistons only. Building the motor is a huge operation, and should be done correctly, and completely: Rods, pistons, studs, bearings, gaskets, etc..etc..

 

Lower compression pistons will reduce your power at the same boost level so unless you raise the boost the APS kit will probably not make your desired 400whp.

I agree with the above statements about doing it all at once, but if you are absolutely going to do one or the other, I would do the rods because that has been point of failure on many FI 350Z's. Best of luck!

 

Lower CR pistons and stock rods will give you much more room for error than forged rods and stock pistons. But if you're going to pull the block apart, might as well change everything else. Will end up being cheaper.

 

I cant think of a bigger waste of money, then tearing apart a motor, and just changing the rods OR the pistons. The parts to rebuild a motor are relatively inexpensive. It's the labor and downtime that is most costly.

Pauter rods are $1170, and Arias Pistons are $750...both shipped.

 

Sharif, in our case there was almost NOTHING available for this motor when we were turboing it (almost 2 years ago). We're ready for it to blow, rest assured it will have forgedinternals.com stickers all over the new motor

BTW, rods from STI EJ20 look smaller than stock VQ rods

 

LOL....Aite I guess ill hit you up when I am ready to boost, thanks for all the replies.

 

LOL...yeah...you trend setters are nuts. I know a guy....name withheld...that was one of the first people to take delivery of the 03 350Z..back in summer/fall of 2002. Anyways, in no time at all, he went direct port nitrous, and was the first guy to make 400whp...or at least one of the first.

Amazing how far along the market has come in 2 short years. The only thing missing is a plug/play standalone ECU. That is the missing piece at this point. HKS ECU excluded, since its not totally plug and play, and its not user tunable.

 

Anyone out there using forged pistons in stock 10.3:1 compression? Anyone make them? When I e-mailed Peter at APS he recommended 9.5 compression if one was to go with upgraded internals.

 

I have driven VQ35s from 8.5:1 to 9.3:1 to stock 10.3:1 compression and noticed no seat of the pants difference between throttle response and the feel of torque and the engines "desire" to accelerate.

Now to only change the rods or only the pistons, like everyone is saying, is a pretty big waste of the labor... however, the question is a valid question and if you must only replace one or the other, I would replace the rods. However I think that the stock rods and pistons are a pretty decent balance for each other... well appearance wise anyway... IMHO it looks like these rods could hold every bit of power that these pistons can hold, and vice versa.

The reason I choose the rods to upgrade over the pistons is because a rod failure will statistically create a lot more damage and often times render almost the entire engine unreuseable. A piston failure is typically no real harm done, there are rare occurances but usually its no big deal.

-Charles

 

Thats an excellent point, melted and cracked pistons very rarely jump through the side of the block or even cause bad scuffing of the sleeves like rods are prone to do.

 

I really would not go to the trouble or expense of forged Pistons or rods if you have 93 octane fuel available - the engine should be very safe at that power level with an APS twin turbo system, just install the APS twin turbo system and enjoy the car until you're ready to get really serious and then build an engine and run higher boost pressure/higher mass air flow.

I'd stick with the stock comp ratio if you're running 93 octane fuel, the APS twin turbo system has massive intercooling so detonation won't be a problem - the off boost engine response and fuel efficiency will also be superior on the higher comp ratio and the ignition timing map can be tweaked around by Mark or Kyle if you want to push the boost a little higher.

That's certainly a better long term idea - if you're going to go to all of the trouble to strip the engine then do pistons, rods, studs, etc, etc, at the one time, this will be far more cost efective for you and a lot less down time.

For what it worth I would always choose to run a higher comp piston rather than lower comp ratio given you have good fuel availabe in Texas, let me know if you ned any other assistance or advice.

Thanks

Peter

 

Thanks a lot for the help peter!