Ahab

I remember reading a question someone sent into a magazine asking how they could get more power out of their Sportmaxx (I think it was a Sportmax) and the writer on the mag recomended getting a new Sleeve and Piston to replace his old one (makes sense) but he suggested buying an aftermarket Sirio(I think) one rather than a traxxas one as this apparently made more power, and was cheaper than a whole new engine.
In theory this makes perfect sense to me, a redesigned sleeve and piston could have higher compression or better porting. But I have never heard anyone talk about doing it on these forums and have never seen an advert for that sort of upgrade.

do they exist? are there any companies that make performance sleeves and pistons for the S25 lump? WHy arent we all doing this rather than getting a whole new engine?

Frost_

My Feedback: (1)

The only set that fit are the stock set... Now, there is an article written specifically on the S25 that details not only port work, but timing changes made at the crank and exhaust port that alter (increase) duration.... These mods will make a difference that is hard to believe...

Go back to page 2 or 3 of the HPI forum and look for my porting SH28 post. In it is a link to the porting guide for the S25 and the recorded before and after numbers (in vehicle).




-EDIT- Here ya go, I did the work for ya[8D] http://www.rccaraction.com/articles/htpporting_1.asp

:Green:

Sweet...[8D]

hybridstone

Ya sirio made em! I ve seen a trxsirio 15 in action not much faster than stock!! get a os18t or rb 23 then you'll see power!!

RC Prodigy

Nah if you want mad power, get the dang sh .28 or Collari .30
Not sure about the power of the Collari, but the SH .28 makes 3.4HP

Ahab

Frost - I saw your porting article, it was sorta what reminded me of what i saw in that mag

So was the trxsirio a one off? it seems such a simple performance increase I am amazed it isnt more common...

Frost_

My Feedback: (1)

It's the only one that I know of... I know (and this isn't the same thing) that Durataxx makes a sleeve for an OS12, but it is a stock replacement. Other than that, I don't know of a company making sleeves and such for other manufacturer's mills. Mybe they are out there, but if so, I haven't seen them.

Ahab

do you think we have found a gap in the market? - or would you say that there is probably a technical reason for it?