MatthewMenze

Hello All,

A little over a year ago I turbocharged my D16Z6 Del Sol, it's still going well and I have a blast working on it and driving it.

I am considering going a bit farther while it's in the garage over the winter. Right now I am sitting around 180-200hp, about as far as I would like to push a stock z6. I would like a bit more power, 250hp or a bit more.

But more than anything I would like to maintain stock compression ratio and pistons if possible, even if it meant limiting the power output a bit. Right now I have a T3/T4 turbo on it, and love the boost curve. I love the Jeckle/Heide feeling between off and on boost, and honestly slight lag makes it more fun when burning around town (for me, obviously this is not ideal for other people). I also love that the car feels basically stock OUTSIDE of boost. I get this is far from ideal from a performance perspective, but I am making my car to maximize my fun while driving it, and this is what is most fun for me. :D

Over the winter I want to do headgasket, ARP studs, rod bearings, and piston rings for some peace of mind (150k on motor) and to learn about taking engines apart. I would also like to put in some upgraded rods while I am there, but if possible keep stock pistons for the follow reasons:

1) Stock Compression
2) Cost Savings
3) I only want slightly more power than now.

While searching I have not really found straightforward answers/advice on this build because most people doing this route replace pistons and rods, and then go all out. I only want slightly more power than I have. From what I understand the rods not the pistons are the weak link, with high compression being a secondary issue.

So my questions are:

1) What kind of reliable power is attainable with only upgraded rods? I can't really find much when searching for this, so a link to a build would be gold here. From what I understand upgraded rods make 250-300+ doable with careful tuning and avoiding knock, though that may be with the assumption of upgraded rods, or just plain wrong.

2) What rod choices do I have that will work with stock pistons? If not, what pistons would be a good place to start looking at to maintain stock compression?

3) Do any allow me to avoid notching block? I have found conflicting answers on this. I am not super opposed to notching though, it's just a consideration for me.

Ideally it would be a set of rods I could just drop in while doing the other stuff, but if that is impossible I would want as close as possible to that ideal.

Thank you anyone for helping me out, I have been searching for a while and finding mixed responses, so it would really help me to just hear it from the horses mouth.

-Matt

NotARaCist

iTrader: (1)

There's a reason you can't find much on upgrading just your rods. OEM pistons and rods use a pressed-in wrist pin, whereas nearly all performance aftermarket pieces will use a floating wrist pin. You can get it to work, but it involves machine work, and the price and time of the machine work basically negates the cost of reasonably priced forged pistons.

While you have the engine apart, there is no reason not to upgrade the pistons. You can still maintain your stock compression ratio, or step it up a hair to get even better performance, both in and out of boost. It's kind of a no-brainer. Do it once, do it right.

Aradin

Hate to burst your bubble but as far as I know you can't use a set of typical aftermarket rods with stock pistons. Someone correct me if I'm wrong but most OE Honda setups are pressed pin, while aftermarket are floating pin.

If you want something cost effective, do a vitara build. It's a cast piston with meaty ring lands. Should have little to no slap and hold the power you want fine. With stock length forged rods the compression will be lower than what you want but there are ways around that via tuning or custom length rods.

Whatever you decide to do, do it right the first time or you'll be doing it again. Building a motor and playing the horsepower game isn't cheap at all.

Edit:NotARacist beat me to it lol.

NotARaCist

iTrader: (1)

Vitara setups basically require a custom length rod. Without one, you drop the CR so low that your car is literally gutless outside of boost, and your gas mileage is noticeably affected in a bad way. Considering how OP likes his T3/T4 setup with the noticeable before/after boost "feel", a Vitara setup on stock rods would be a comically bad idea. Yes, you can use custom length rods, but with the time, effort, and cost of finding them, what's the point? Just get some Eagles, toss some Supertech pistons on them, have an engine that can easily surpass 300, and call it a day. Your engine isn't properly built unless you feel like it's overbuilt.

MatthewMenze

Okay, that scraps that idea then. Since I am now considering a vitara or similar build, is there any advice or starting points you would suggest when picking a piston? Or considerations that are commonly missed? (I will be researching as well, but I like to compare my research to direct answers).

Also, what rods don't require notching of the block? I can never seem to get a straight answer. Maybe it is that they all require it?

Thank you so much for your time!

NotARacist's second post showed up while writing this post. Thanks for info!

justYncredible

iTrader: (1)

OP....
all your answers are here on this site. no need to get a "straight answer" from someone. 1 of 2 things will happen

1) they will tell you to search the site
2) repeat the first step

NotARaCist

iTrader: (1)

Check out this link as well, specifically for the block notching stuff.

If you're on a budget, you aren't going to get much better than Eagle rods and Supertech pistons. They're cheap, but they do the trick.

LTCxD2B

If some how u manage to not damage the stock pistons while removing the wrist pins ... You will crack a ring land with the new power ... 10 + year old pistons man

MatthewMenze

Okay, I am definitely going to go the eagle rods/supertech pistons route, barring some amazing deal or some such.

Now I was planning on pulling my D16Z6 and then building that over winter, but I the chance at a very good deal on a A6 bottom end. From what I understand the only big difference between the Z6 and A6 bottom end is the pistons...Which will be changed anyways. I've also heard mixed opinions that the A6 bottom end is a bit tougher. The only reason I ask is most Z6/A6 threads I find devolve into people arguing about using them in hybrid engines and such, and not just throwing a z6 head on a built bottom end. There appears to be arguing about timing them, as well as some fitment issues?

Does that sound right to everyone? It would be much simpler logistically if I had a running engine in my car while I built up a bottom end (nobody likes a shell stuck in their garage).

My plan currently is to buy the A6 bottom end, build it. When it is done, I will swap the motors (and also my Z6 head to the A6 bottom end). Allowing me to only have a few days of downtime, instead of the engine being out of my car for however long.