174 replies to this topic

[OrangeCrush86]

The way this website handles images is really frustrating so it's hard to read. The car made 115hp/99tq max. The AFR looks decent to me at ~13 and down to 12.5 before rev limiter.

[Steve Scheifler]

Yeah, my first thought was “you suck at taking pictures “. But my second thought is that only Dave can tell you how it stacks up against other 1.6s on his dyno in it’s current configuration/version.

[chris haldeman]

120+ On Dave’s dyno is where you need to be. I can’t imagine trying to race a car 5-8hp down in this class

[38bfast]

Every dyno is different. The same car traveling around to all the SM shops will produce different numbers. Most everyone’s dynos are repeatable to them selves. But trying to compare numbers from one to another dyno is pointless. The best way to communicate power is +/- off the best seen off THAT dyno. Example is: that car was -2 off the best 1.6 I have seen on this dyno. Or your 1.6 is +1 to the best 99 we have seen.

[chris haldeman]

Edited my post for you

[OrangeCrush86]

I was told HP wasn't that bad, but torque numbers are low. I didn't have time to speak with Advanced in person. I'm sure the engine is tired. It probably has 7 or 8 years of racing on it. Previous owner said it was a "Sunbelt" motor, but they don't even seem to be in business anymore.

[Steve Scheifler]

Sunbelt. If it’s any consolation, it probably isn’t even close to “legal” anyway. Depending on exactly when it was built it may have incorrect cams, valve springs and even pistons. If the pistons are wrong then the block may be too short (we do have a minimum block height, right, or is that just the head?) Anyway, the pistons had a higher pin location so they could deck blocks enough to square everything up without the piston smacking the head. For awhile they were even plugging the piston oiling jets to reduce windage, which proved to be a really bad idea. And they were mucking around in the heads, especially behind the valves. If it’s old enough, like 2006, you could find all of that and more, making even the option of just refreshing or replacing the head risky.

[Danica Davison]

 I can’t imagine trying to race a car 5-8hp down in this class

 

What you talkin bout, Wilis?! We have all been racing 5-8hp down from Drago for years!

[Bench Racer]

http://mazdaracers.c...ead-2034/page-3

 

Page #3, post #51

 

File color car year

Blue 2002
purple 1999
red 1990

 

I get it, we don't race dyno files, comparison purpose from 2013.

[OrangeCrush86]

Sunbelt. If it’s any consolation, it probably isn’t even close to “legal” anyway. Depending on exactly when it was built it may have incorrect cams, valve springs and even pistons. If the pistons are wrong then the block may be too short (we do have a minimum block height, right, or is that just the head?) Anyway, the pistons had a higher pin location so they could deck blocks enough to square everything up without the piston smacking the head. For awhile they were even plugging the piston oiling jets to reduce windage, which proved to be a really bad idea. And they were mucking around in the heads, especially behind the valves. If it’s old enough, like 2006, you could find all of that and more, making even the option of just refreshing or replacing the head risky.

 

I think this engine was probably suspect in the past because the previous owner gave me an SCCA cam measurement sheet. The cams from this engine were checked by the SCCA and confirmed legal.

 

I will have to decide if it's worth 6k for a new motor. The car is solid and Dave said it's very square. It scaled out really nice. Thanks for the inputs.

[Steve Scheifler]

Have you done a leak-down to determine what if anything is leaking? Have you checked compression with a Whistler? If a leak-down doesn’t give any indication of badly worn rings but does indicate issues with valves, I would check it very carefully with a Whistler and record the numbers. Then I would pull the head and carefully inspect the bores and piston tops. If there is still no reason to be concerned about the bottom end then consider doing just the head, that’s where nearly all the gains are.

Check the head for any compliance issues that can’t be remedied. If it looks good send it to one of the known SM builders/suppliers for confirmation and evaluation in terms of a refresh. If it’s a particularly crappy casting or has other issues you might be better off buying one outright rather than reworking that one, the difference probably isn’t all that much.

Back to the Whistler, with those numbers you know whether you can afford to shave some off the head without going over on compression. You also know how much difference there is from cylinder to cylinder. (If you have high leak-down from the head that can distort even the Whistler reading) A crappy casting can have significantly different size combustion chambers, which you’ll see in the Whistler readings. Likewise, if some valves are sunk deeper than others or some seats were replaced (raising the valve) that chamber might be larger or smaller than others. If anything suggests such differences then it’s best to CC all four, again to judge the value of a refresh vs. replace.

A good shop can do all this for you but it is time consuming and in the end might run up the cost of a refresh to equal a replacement. If you can do a lot of it yourself and have the time, then you might even get away with nothing more than a careful valve job and light shave at a local machine shop. No way to know without some initial work though, and of course there is always the chance that the bottom end will decide to take a crap soon after you deal with the head. How’s the oil pressure?

[OrangeCrush86]

http://mazdaracers.c...ead-2034/page-3

 

Page #3, post #51

 

File color car year

Blue 2002
purple 1999
red 1990

 

I get it, we don't race dyno files, comparison purpose from 2013.

 

How do you see the graphs. The link is broken for me.

[Steve Scheifler]

I was told HP wasn't that bad, but torque numbers are low....

For those confused by this given that HP is simply calculated from torque and RPM and therefore they are both “high” or “low” together at any given point of the chart, the above statement should suggest that mid-range power (at or around peak torque RPM) is suffering more than it is at peak HP RPM. That in turn must be evident in the *shape* of the power curve if laid over the curve of a healthy engine.

[OrangeCrush86]

For those confused by this given that HP is simply calculated from torque and RPM and therefore they are both “high” or “low” together at any given point of the chart, the above statement should suggest that mid-range power (at or around peak torque RPM) is suffering more than it is at peak HP RPM. That in turn must be evident in the *shape* of the power curve if laid over the curve of a healthy engine.

 

Dave sent me a nice comparison. A quick evaluation shows my engine is down on both torque and power across the entire graph. Minimum is a about 4%, max is about 8%. Basically if you looked at a new 1.6L graph, shift it down ~6% and it's my graph lol.

[Bench Racer]

How do you see the graphs. The link is broken for me.

When I click on the link posted the dyno graph shows perfect as it should. Try another process to get to the post. click on "Spec Miata" heading, scroll to page 21, scroll down until you view "parity thread #2034." Open page #3, post #51. The point of this post is you'll view 3 different first class engines from Drago all tested on his dyno.

[davew]

Remember those are 2013 numbers. Lots of things have changed since then. Plates, 1.6 headers etc. Good comparison, but not 100% accurate

[Bench Racer]

Remember those are 2013 numbers. Lots of things have changed since then. Plates, 1.6 headers etc. Good comparison, but not 100% accurate

It was noted the numbers were 2013 and until someone in the know (dyno owner) posts 2018 comparison data, the 2013 overlay dyno graphs are all we have. Overlay not even required, post graphs for same cars as Drago did and it'll be called, thank you. 

[LarryKing]

1.6 headers?

 

Everyone optimized their 1.6 headers long before it was legal.  

[Steve Scheifler]

1.6 headers?

Everyone optimized their 1.6 headers long before it was legal.

Wrong, we certainly did not.

[LarryKing]

 

Wrong, we certainly did not.

Well, then you were in a very small minority.