The calculated 2 hp gain doesn't take into account any other modifications. Previously with all of the bolt-ons he was still running on the stock computer.

When he installed the new pistons for more compression he also did a custom tune on the car. Not only did the custom tune take into account the new pistons, but also optimized the bolt-on modifications that hadn't been taken into account in any significant manor by the stock ecu.

He has a dyno graph on the other site, and at this point I have no reason to doubt it. He also posted times from a trip to the track as low as 14.8 with an auto. No time slips posted, but as I said before, no reason to doubt him.

 

Oh I don't doubt it, I'm a firm believer in tuning. The right combo of parts and dyno time makes a world of a difference.

Does anyone have the bore/stroke/cc volume specs for our motors? Trying to see if it would be more cost efficient to simply mill the head. Also, do we have MLS head gaskets? Multi Layer Steel...

 

Before you go milling the head... Has anyone ever checked the valve clearance? I think Twiddler would have been the most likely candidate, and he never did. I know early on he was considering shaving his head, but backed off because he didn't want to get that deep and hadn't checked the valve clearance.

Now that I think about it, I wonder if that will be an issue with the Prius pistons.

 

Yup, all things to check. Are our engines interference design?

 

our motor's are interference but no where near as closely interferenced as a 2zz's are.

 

tuning , dropping the engine , removing old pistons , installing new pistons , as well as probably changing rod bearings just as a precaution , and i don't know the price on just the pistons. his 5k price may have been including all his bolt ons but i don't believe so.

 

Quick question... since I am pretty new to engine modifications this extensive...

When you say "interference design" does this mean that the valves actually open up enough that they protrude into limits of the piston stroke?

So, you get your pistons and start tearing your motor down yet Darren?

 

Interference means that if the timing chain breaks, the valves will "interfere" with the pistons. And by interfere, I mean smash into each other causing lots of damage. Seen it happen a few times, it's ugly. Valves get bent, often ruining the valve guides/seats in the head. Sometimes the pistons will get gouged to the point that they are useless.

 

That's about what I figured.

 

No zpi pistons.

Hey darren, go for it. But keep in mind what i told you earlier, higher compression doesn't always equal better gains. For the 11:1 pistons, without management i was running a horrid afr, i can only imagine 12:0:1+ compression will cause as far as headaches, but if i were you i'd go standalone with it. I don't think a piggy back will be enough for you.. Could be wrong though. So far my ecu hasn't re-set anything as of yet.

Oh, and that $5k isn't just e-manage and pistons. That $5k is for i/h/e, mid pipe, engine damper, 11:1 pistons, management, tuning, and so on. I plan to go with itb's, atf cooler and a few other things by the end of the year. So i'm hoping to hit 150whp+ by december.

Someone doubted my track numbers on there because of the 60ft and trap times, but i think they forgot i'm an auto. Auto's can do funny things. haha.

I plan to get a video or two up in the upcoming weeks on clubxb, i'm done with this site only posted since i was brought up. Good luck darren, let me know if you need any help with anything.

 

nice.... and people said it couldn't be done with this motor....

 

Its because everyone who dismisses the motor has yet to attempt a full n/a build, aside from the basic i/h/e route. Which is fine, but people need to stop talking about stuff they haven't attempted yet. And its obvious most people can't tune. lol

But darren and I you should look out for, i think i've gotten him more into n/a since i met him, at least for this car anyway. Most of my experience is n/a, if it was boost discussion i'd probably have less whp.

Hey darren, are you for sure going to do this yet or still debating? It should be Cali legal but its debatable.

 

just wait... in about 2 or so years ... even engine swaps will be an option to go with on the xB.....

 

Hey Tony. Good to see you posting on this topic. I saw the thread on clubxb after Darren mentioned it. I was totally excited to see it.

If it isn't asking too much I would love to see a break down of what you have done, and where the money was spent. Things like, who built the pistons, what i/h/e you are using, who did the tuning, and how much each item cost. I think it would be good for people to see not only how much a NA built costs, but where those costs are.

It is also good to see that the 11:1 seems to be working out with only an e-manage piggy back. Is there a reason you think you would have to go to a stand alone instead of a piggy back for 12:1? Is it just that the compression would push the ecu (even with a piggy back) to far outside of the maps?

I'd really like to hear whatever you have to say in regards to your NA build. You might be one of the few out there offering hope for the poor Californians under the oppressive thumbs of tree hugging liberals.

 

mmm engine swaps equal to pure sex

 

Today At work I was Bored so I was looking up the specs between our cars and the prius on SHOPKEY the compression ratio for the 1NZ-FXE pistons are 13:1. if anyone is interested i will upload the full specs of the two for comparison to a jump drive and bring em home to post em

 

If you can do it, I say go for it. Even if it doesn't get us any closer to our goal, it would be cool to see.

 

Although I have not seen the Prius pistons, the higher compression ratio can come from a few differnt ways; the pistons have a huge dome to raise the compression, the combustion chamber on the Prius head is worked/massaged for more volume, they head gasket may be much thinner than that of the xB, xA or Echo or the block itself is milled or a combination of all.

All in all, I think if the bore and stroke are the same,I wouldn't see why this couldn't be done. You may have to take out a little timing and run high octane race gas, but it would be a pretty inexpensive power mod if you have some engine building experience.

 

Virtually 100% of the time, when you change your compression to 11:1 or higher, you have to run 91 octane. Very few cases can you run lower octane and have high compression.

 

the prius if i remember correctly is 13:1 mostly from pistons. not 100% been awhile since i checked specs.