Ericy321

I dont think you could just put 1.8 pistons and the head gasket on one of ourt cars and expect a decent gain at all. Without a good exhaust, good intake and some decent cams, maybe even headwork I wouldnt be surprised to see a loss. Maybe youll have a little more top end but not enough to make it worth the work. Im also assuming most of the people thinking about this mod aren't going to be doing the work themselves and labor charges alone would kill for the small gain if any.

And the thread wasnt even about the pistons it was more about the cam. The specs on it are here somewhere. And like I said at first I highly doubt that you would hit the valves with pistons. Im sure its been done in Korea a million times with the same setup and I would think we would know if people were smacking valves

AGreen

Well, although it got hijacked a few times, I think I found my answer.

Anyways, I'm no stranger to doing major internal engine work, which is why I was contemplating the 1.8 pistons/ xd headgasket (i've already got the 1.8 cam on it). Not with the 1.8 rods though, because apparently it will defeat the purpose (ie, lower compression).

Now, with the proper fuel monitoring (i use an safcII with an NGK powerdex wideband) and a slight possibility of needing larger injectors, I'm sure that with tuning it, you'll see more than just a 3% increase in power. Also, since the head's already coming off to replace the pistons and gasket, then I'll probably port and polish it, and either reseat the valves and clean everything up nicely, or take it to my favorite local machine shop where I'll get a 3 angle valve job.

For 139 bucks, plus the head gasket set cost, it's a relatively cheap engine modification that will (potentially, since I've not seen anyone do it yet) produce some *decent* power for the price. On top of which, the engine will practically have been about half rebuilt, so with 102,000 miles on the stock one, it's either time to get a new motor, or get a new car. Both of which are more expensive than replacing some pistons!

Maybe I'll do a how to with dyno results.... cool.gif

One more thought, before i lose it

If the rd1 engine has 10.3-1 CR to begin with, and it's raised to 11-1, then that's a 6.8% increase in compression. I'm not saying it's going to be a huge power increase, but it'll definitely be significant.

Some specs I found:

2.0
stroke: 93.5mm
Bore: 82mm
C/R: 10.3:1
Intake Lobe Height: 1.75 in

1.8
Stroke: 85mm
Bore: 82mm
C/R: 10.0:1
Intake lobe height: 1.7342 in

Zman

<div class='quotetop'>QUOTE (AGreen @ Oct 12 2007, 09:48 PM) <{POST_SNAPBACK}></div><div class='quotemain'>If the 1.8 pistons were used with the xd head gasket in a 2.0 to obtain 11.0-1 compression, could you also use the 1.8 cam, or would valves start hitting pistons at that point?</div>


<div class='quotetop'>QUOTE (Ericy321 @ Oct 13 2007, 07:40 PM) <{POST_SNAPBACK}></div><div class='quotemain'>...
And the thread wasnt even about the pistons it was more about the cam...</div>
33.gif

you are owned.gif nana.gif

I am joking Ericy, but the topic is completely about the pistons man.


<div class='quotetop'>QUOTE (Ericy321 @ Oct 13 2007, 07:40 PM) <{POST_SNAPBACK}></div><div class='quotemain'>I dont think you could just put 1.8 pistons and the head gasket on one of ourt cars and expect a decent gain at all. Without a good exhaust, good intake and some decent cams, maybe even headwork I wouldnt be surprised to see a loss. Maybe you'll have a little more top end but not enough to make it worth the work.</div>

I don't agree; compression has nothing to do with top end, it raises torque and power trough out all rpm range (of course you wouldn't tell the difference at 1500-2500rpms...); we are talking about a FULL POINT in compression, going from 10:1 to 11:1 in a NA engine, is a noticeable difference no matter other mods; we know of course that every mod compliments each other; of course with a more agressive camshaft and I/H/E as AGreen sais he has, the gains are going to be bigger and more noticeable. Also, our cars show bigger gains from breathing mods than other engines, so I don't think you need to have state of the art I/E, I htink with just OEM Muffler removed (much better if it's 2,5" exhaust line from header to back) and a cone filter (much better if it's a CAI) you would take advantage of compression raise; I don't think we need headwork at all to benefit from this. ALso you would take advantange from it even with OEM intake camshaft, but of course it would be better with the 1.8 intake cam (don't think you need more than that.


<div class='quotetop'>QUOTE (Ericy321 @ Oct 13 2007, 07:40 PM) <{POST_SNAPBACK}></div><div class='quotemain'>Im also assuming most of the people thinking about this mod aren't going to be doing the work themselves and labor charges alone would kill for the small gain if any.</div>

You have an interesting point there... if you compare the gains with the gains of Forced Induction, then yes, it could be seen as not so important, but think that you are NA and have to stay that way, the it is one thing that can help significantly... I'd put it prior in the list of NA mods to let's say headwork.
About the cost, it depends, in the USA labor is a rape, here I can get a full overhaul at a dealership for $300 (labor) so it's not that expensive and could be worth if you already did a good heather, full exhaust, CAI, AirRam, camshaft and still want to thorow some $$ in your engine.


AGreen:

-where did you find those specs? Lift on the 1.8 camshaft is bigger than in the 2.0
-There is someone who has done it here; Mad_john had this mod in Korea when he was NA
-Check TDonnels threads on dynos and headwork, he has done extensive research and trial about this, and it seems our heads are not really sensible to port/polish or even valve job... I am not saying you shouldn't do it, but that is something I don't know if it is really going to add a lot, although it's a lot of work... if you are doing it yourself and is not going to cost, the OK, if not, check if it's worth it.

AGreen

*Off topic---->

That's true. Labor is about a bigassed rape here in the us. But it's somewhat justified. I'm an ASE certified, (Ford/Mazda trained) technician. The cost of overhead in any shop that's trying to make it in this cruel world is phenomenal. There are so many machines and a ton of special equipment (including the standalone ecu programmers and dataloggers) you must have to operate a shop. And all that stuff has to get paid for. The funny thing is that people think that mechanics go home fat dumb and happy with a big check they just got for working on your car, but it's not true. I was barely scraping in 15 bucks/hr at my old job. That sucks, compared to the 85/hr we were charging! The profit goes back into the business, which was literally almost a million in debt. (I worked at an independent garage)

Back on topic---->

Those specs came from Mitchell OnDemand5, which is the online tech manual my shop subscribes to. I searched for the 97 tiburon, and it listed all the specs for both engines. Sadly, it didn't reveal the length of the connecting rods.

I don't really want to get too carried away with the whole N/A power thing though. I'm not really looking to make a ton of power, just enough to run with something better and classier than a stock civic laugh.gif Too much more and I might as well go F/I with all the money I'll be sinking in it. The airram intake looks pretty, but it's 600 freakin bucks!

lukeyn

I'd be interested in the dyno results...Or if anyone had a dyno from someone with the 1.8 pistons

Zman

Mad_john should throw a couple words here... he should know.