70 replies to this topic

[Steve Scheifler]

Is anyone willing to share their results from before & after cleaning up a 1.6 header per the new rules? My first effort yielded zero gain. I didn't expect much but hoped for something measurable. I did not have access to a flow bench but as restrictive as they look that should amount to fine tuning if there is anything to be gained.

To get rapid turnaround so conditions were the same I started with two very similar untouched headers and cleaned up the welds on one. This seems adequate for starters since we have two cars that are effectively identical and very repeatable on the dyno. Either there are no significant differences or the differences perfectly net to zero.

Bottom line, the headers on our cars appear not to be the weak link. Even with the old Mazda "value" down-pipe which has no internal welds, the entire usable power band was unchanged after swapping the header.

Anyone else test and willing to share?

[Chris Ashcraft]

That's not what i wanted to hear! 

[ECOBRAP]

Been waiting to hear something about this, kind of figured this would be the case. Thanks for saving me some time and money...

[Bruce Wilson]

Not disagreeing or agreeing with your assessment Steve, but the discussed gains did lie within the noise range of dyno "measurement", therefore it would take a pretty large sample of cars and dyno runs to really gauge effectiveness of the rule change.  I'm sure you know that (thus why you are asking for shared date), but just stating here for everyone else's benefit.  How many pulls did you do before and after?

[Bench Racer]

The common sense gain works for me.

[Ron Alan]

Any one of the 3 changes may not show on dyno...or noise. Combine all 3 and then report. Plus I would think 2 of the 3 changes may show more on track than on a dyno. I believe the change will help many race with better power until the checkered. The flow bench certainly shows a difference in ground welds. It also shows a difference between untouched headers. Good 1.6 power requires all elements to work/flow above average. Why not take advantage of every free potential gain!

[Steve Scheifler]

I have literally hundreds of runs on these two cars since this time last year. When I control the variables the power curves from last spring still overlay exactly on top of the new runs. I'm talking +\- a small fraction of a HP up & down throughout the runs with a net of essentially zero. It defies what a lot of people assume about runs on different days, it just takes careful work. So I'm confident that my noise on this, runnning the same day, is quite low and if there were a genuine average gain of even 0.5 through the usable range it would have been plenty evident. I also do fixed RPM max load full throttle "runs" at various points which makes it real easy to spot changes. I got nothing. So yes, my sample is minimal but my confidence in the results in this one case is high. When I have time for the other car I will be using the brand new header and take the time to use it for both before & after, but since the engines make almost identical power now I don't expect much. Perhaps if we were making better power then this would show benefits, but first we need to figure out where our engines are weak.

The good news is that maybe we haven't been giving up much to the cultured peaches all this time, but the bad news is that this little gift will do nothing for us against other models. The last thing we needed was a placebo.

[Ron Alan]

My guess is your results are accurate as well Steve. But using the same header is a better sample for sure.

Last year I flowed 4 stock headers. I used a volume of air that is about what the motor pumps at full tilt. 3 headers flowed within 3% of each other...the 4th was almost 10% better than those 3! I saved that one

[Steve Scheifler]

I suspect, even fully expect, that on a bench the cleaned up header would flow better. So my results suggest that the rest of the engine is unable to utilize that capacity. Ports and tubes that are too large kill velocity and you lose power, so the big ugly welds at the ports may not be a significant problem at these power levels. And since I'm not touching the down-pipe it seems pointless to completely remove the welds at the collector end, better to blend towards the exit so the gasses don't hit a ridge at the joint, would you agree?

[Alberto]

I have 4 unmodified 1.6 headers and none of them have what I consider "big, ugly welds" so I never saw the point of this "allowance".  

Unlikely that the overall impact of this when combined with other allowances is likely still to not result in anything measurable.  

Should have just allowed a header so people aren't forced to result to junk yard diving and flow testing.

Not surprised by your results but happy to read about them.  

 

I'm glad I run Sealed Spec Miata

[Sean - MiataCage]

Here is what we found on an engine dyno.  Fresh pro motor, chassis dyno's as A+ motor.  Used the same header tested on the same day only down time was grinding the header.

 

RMP - HP / TQ

5000 +0.3 / +0.3

5100 +0.4 / +0.5

5200 -0.2 / -0.2

5300 -0.7 / -0.6

5400 +0.7 / +0.7

5500 +1.1 / +1.0

5600 +1.4 / +1.3

5700 +1.1 / +1.0

5800 +0.9 / +0.9

5900 +1.5 / +1.3

6000 +0.9 / +0.8

6100 +1.2 / +1.1

6200 +0.8 / +0.7

6300 +0.7 / +0.6

6400 +1.5 / +1.2

6500 +1.7 / +1.4

6600 +1.8 / +1.5

6700 +1.5 / +1.2

6800 +2.3 / +1.7

6900 +2.6 / +2.0

7000 +2.9 / +2.2

[cam]

Here is what we found on an engine dyno.  Fresh pro motor, chassis dyno's as A+ motor.  Used the same header tested on the same day only down time was grinding the header.

 

RMP - HP / TQ

5000 +0.3 / +0.3

5100 +0.4 / +0.5

5200 -0.2 / -0.2

5300 -0.7 / -0.6

5400 +0.7 / +0.7

5500 +1.1 / +1.0

5600 +1.4 / +1.3

5700 +1.1 / +1.0

5800 +0.9 / +0.9

5900 +1.5 / +1.3

6000 +0.9 / +0.8

6100 +1.2 / +1.1

6200 +0.8 / +0.7

6300 +0.7 / +0.6

6400 +1.5 / +1.2

6500 +1.7 / +1.4

6600 +1.8 / +1.5

6700 +1.5 / +1.2

6800 +2.3 / +1.7

6900 +2.6 / +2.0

7000 +2.9 / +2.2

Wow, I very surprised that it made that much of a difference.  Mind sharing if the header you cleaned up had intrusive welds?  Thanks for sharing actual results. 

[Sean - MiataCage]

Hello Cam,

 

See below.... Dale posted them.  Thanks Dale.

 

Sean

[dstevens]

[Todd Lamb]

I can't say this thread surprises me. There are those that know what they are doing, and those that don't. 

 

The 1.6 has always benefited from a better flowing exhaust. From parts binning to find a good header, to searching for the ever elusive value pipe, to grinding down the welds and going through a lot of effort to conceal. That wasn't all being done for years just for zero gain (to use a common argument from several in this thread).

 

Don't accuse the SMAC of placebo changes just because you can't figure it out.  If you didn't see any results, check your work.

[LarryKing]

 

Don't accuse the SMAC of placebo changes because you can't figure it out. If you didn't see any results, check your work.

 

Wouldn't it have been easier to just spec a header? (And perhaps more in keeping with the philosophy of a spec class?)

[Sean - MiataCage]

Wouldn't it have been easier to just spec a header? (And perhaps more in keeping with the philosophy of a spec class?)

 

Spec'ing a header would have required everyone to go out and spend $400.00 ish for a part that everyone already has.  I'm not sure you can get any more Spec than the factory piece. The new rule in my mind does the following:

 

1. Eliminates purchasing and flowing multiple headers looking for the magic one.  This saves the competitors money.

2. Allows for the repair of existing cracked headers.  This saves the competitors money.

3. Allows for a person who is fully prepping their car to achieve some minor performance gain.

4. Anyone with a grinder can do this without sending it out to a shop to be done.  This saves the competitors money.

 

It's very easy to say go to an aftermarket header.  There are lots of issues with that.  Consistency of part, availability, price, future price or price hold, etc.  How do you mount a heat shield to an aftermarket header?  As has been discussed at length, lower intake air temperatures are important for making power.  None of the aftermarket headers we discussed had a provision for mounting the heat shield.   So if we would have gone with an aftermarket header it would have cost every competitor $400.00 ish and then you would have increased under hood temps and potentially compromised the intake air temps.

 

Please understand that when SMAC evaluates things, we do our very best to use fact and data and we try to take into account what it will cost the competitor and we try to minimize the cost as best we possibly can.  

 

Before someone throws out some $99.00 Chinese E-bay special header...... No, No and absolutely No.

 

Thanks..... Sean

[LarryKing]

Mr. Lamb's comments suggest that not just anyone with a grinder can achieve an improvement.

 

Would header wrap accomplish the necessary heat abatement?

 

What have you got against China?

[davew]

 

 

What have you got against China?

 

Nothing, I love their food

[Sean - MiataCage]

Mr. Lamb's comments suggest that not just anyone with a grinder can achieve an improvement.

 

Would header wrap accomplish the necessary heat abatement?

 

What have you got against China?

 

I think Mr Lamb's comments refer to the fact that there is far more with a dyno number than a header grind.  Too many moving drivetrain components that play a part in getting the minor header gains to the rear wheels.

 

Header wrap not legal.....  And it would be more money the competitor would need to spend on top of the $400 ish, so lets call it $500 ish.

 

Trump is going to put China in a time-out and we will not be able to get any more parts from China ever....