ACE 150 vs 250 vs 350 (show me the dynos)

[Irace86.2.0]

The pipes I got were used. I'm the third owner of the header, and I was told it had a repair from a crack that occurred at one of the main flanges. These flanges are welded on the inside from the manufacture, and there are a few tack lines on the outside. The repair work looks good, but I plan to reinforce the area with more welds on the inside and out. The overpipe to frontpipe flange has welds on the inside and outside. The overpipe to header flange has welds on the inside, but is only seem tacked on the outside. I will likely add more welds to that end.

The header was also missing the plaque, which seems to have broke off. Because it is on the outside of the header and just tack welded in place, I am not surprised it broke off during heat cycles, as it probably was cooler than the pipe. There is no evidence that it was cut off or pried off, which would be hard to impossible to hide.

I am a novice welder, but the welds looked good from the outside and could use improvement on the inside. I used a borescope to examine the welds on the inside and take a few pics. First, a good pic:

This is from the overpipe. The weld had good penetration, and it looks like it was back purged, as the inside and outside look the same without any pores.




In this picture we can see a solid weld at the pipe union. The line running down the pipe and the line in the right lower section are welding lines from making the pipe, where the manufacture of the pipe rolled sheet metal, welded the pipe then ground down the weld. The line mid right is the center of the merger section, which didn't have the best penetration.




The rest of the picture are from the header. Here we see welds that penetrated through the metal around the O2 sensor bung, and we see another merger seem with no penetration.






Here are a few more pictures of sharp edges. This doesn't mean the weld will fail, but if it did fail then the answer could partially or entirely be due to a partial thickness weld.

[Irace86.2.0]

Originally Posted by 86TOYO2k17

For the primary did you measure from engine side flange to the 2nd weld at the end of the 4-2 merge for the primary length?
And then for the secondary runner length measure the header starting at the end weld of the 4-2 merge to flange, and then on the OP from the flange to the 2nd weld at the end of the 2-1 merge. The merge portion (beginning weld to end weld) i would assume would be considered a continuation of the pipe length before it all the way up until it is fully/finally merged into the 2 pipe for the primary pipe or 1 pipe for the secondary merge.

Did you ever dyno your setup as is to get a rough comparison of the after?

Or i think a better test do from 4000-7400RPM in the highest gear up to 5th gear as possible preferably at least (4th to extend the data pool), go in both directions to account for any incline/decline/wind and avg the two runs. Can use ecutek datalogger to get the times, record time starting at 4200 and ending at 7200rpm. If you can repeat this 2-3 times would be even better. Record the weather conditions as well. Then swap over headers and in as similar conditions as possible repeat the test and see if you have any substantial differences in data. numbers on a dyno are cool but real world application/improvements are even better. If one shows 10whp more or less on a dyno but then both are within 1/10th of a second on this test the whp difference is probably inaccurate and from "testing error"

Yes, I measured from the outside/tube-side of the flange where the runner starts, and I finished the length after the merger where 2 pipes were now 1 pipe. I repeated the measurement from that weld to the end of the next merger at the weld for the new pipe. I included the length of the merger sections in case anyone wants to back math or if anyone wants to compare merger sections with another header. For instance, the JDL 4-2-1 EL header appears to have the same length merger section, but the angle is slightly more open in order to clear the slip-over pipe ends.

I have never dyno'd my car, but I am in the process of updating my DT. Even if the header was the only change, I believe Bill versus Zach is doing my tune this time, and the tune likely includes general updates from product development over the last two years. I don't know if it is an apples to apples comparison. Also, I like your idea, but it would be hard to know where the power was added by datalogging the performance without going pretty crazy trying to account for all variables. The idea of this thread is to better understand and see where does the curves change for the 150, 250 and 350.

[86TOYO2k17]

@Irace86.2.0

I’m a semi wannabe professional weld critic. Those welds look great.

You have JDL 4-2-1 now and switching to ace 150?

Could do the test but noting times at 500rpm intervals possibly one is noticeably faster at 4200-5700 and the other 5700-7200 even if both have similar 4200-7200 times. I would suspect the JDL 4-2-1 would be quicker early and 150 quicker later. Not 150/250/350 specific but still could be good data if something substantial comes from it.

[Irace86.2.0]

Originally Posted by 86TOYO2k17

@Irace86.2.0

I’m a semi wannabe professional weld critic. Those welds look great.

You have JDL 4-2-1 now and switching to ace 150?

Could do the test but noting times at 500rpm intervals possibly one is noticeably faster at 4200-5700 and the other 5700-7200 even if both have similar 4200-7200 times. I would suspect the JDL 4-2-1 would be quicker early and 150 quicker later. Not 150/250/350 specific but still could be good data if something substantial comes from it.

Penetration could be better.

I have the OEM headers now.

I’ll consider doing a datalog.

[shadowking1711]

Originally Posted by Irace86.2.0

I was searching, and I couldn't find a single dyno for someone running an Ace 150 or 250, except for RHD cars, which was 250, and it seemed to leave some of the torque dip in place.

I get that removing the torque dip is the utmost concern for NA applications, and low end torque is desirable for many people running superchargers too, especially centrifugal superchargers, but I was surprised to see nothing on the comparison between these difference overpipes. I would assume some people are doing track sessions and would want more power up top.

Does anyone have a dyno graph comparing these different overpipes? I am especially interested in any graphs comparing these overpipes with forced induction. I have a Harrop supercharger, and all I have seen are numbers and dyno graphs from the Ace350 with the Harrop/Edelbrock.

The other thing is that the Ace150 is essentially a slightly longer JDL 4-2-1, but the JDL header seems to fill the torque dips on every dyno I've seen posted, so shouldn't all the overpipes fill the torque dip?

So Question I have a Vortech Supercharger (centrifugal) and I currently have the Borla UEL headers I am looking for a new header to maximize the top end power of my Supercharger I was looking at the JDL 4-2-1 but now I think the ACE 150 may be better. Any Advice? Attached is my dyno chart (363/273). I don't really want more Torque because I know that may break something in my engine.


Thanks in advance.

[CSG Mike]

Originally Posted by shadowking1711

So Question I have a Vortech Supercharger (centrifugal) and I currently have the Borla UEL headers I am looking for a new header to maximize the top end power of my Supercharger I was looking at the JDL 4-2-1 but now I think the ACE 150 may be better. Any Advice? Attached is my dyno chart (363/273). I don't really want more Torque because I know that may break something in my engine.


Thanks in advance.

The 350 is actually going to yield more power; the 150 is meant for high revving built engines, FI or not.

[shadowking1711]

Originally Posted by Doozer

I used to know lengths but have forgotten the exact figures.

Here's a pic of 150, 250 and 350 side-by-side for reference.

The closer the merge to the engine = higher HP
The closer the merge to the rear bumper = more torque

Harrop used to use the old CS400 (before the RHD350) as I guess it complemented their roots charger. The Harrop time attack car switched to the Anaconda 48 (4-1) at one point a few years ago but I have no idea if they still use it.

Track cars are usually always at high rpm so the 4-1 typically suits the cars better.

Somewhere there is a dyno chart for all headers which is where the numbers in the previous post came from. I just can't find the charts anymore

So from this one post it made me think the 150 would be better for the top end.

[Calum]

Originally Posted by CSG Mike

The 350 is actually going to yield more power; the 150 is meant for high revving built engines, FI or not.

I don't follow. The 150 is meant for high revving, where the engine makes the most power, but the 350 makes more power up top? Or do you mean the 350 makes more area under the curve?

[Irace86.2.0]

Originally Posted by shadowking1711

So Question I have a Vortech Supercharger (centrifugal) and I currently have the Borla UEL headers I am looking for a new header to maximize the top end power of my Supercharger I was looking at the JDL 4-2-1 but now I think the ACE 150 may be better. Any Advice? Attached is my dyno chart (363/273). I don't really want more Torque because I know that may break something in my engine.


Thanks in advance.

The only way to add horsepower without effecting torque is raising the redline. Any addition of horsepower will require the addition of torque. If you meant you don’t want more peak torque then you are probably out of luck because your peak torque is really close to redline. It would be hard to try to extend the torque curve to redline with just a header without adding to the peak. Even if you could, I don’t know if the Ace 150 is ideal for this. Maybe it is. We have comments and suggestions, but I still haven’t seen a dyno yet. Technically, a 4-1 header might do more for top end, but runner length might be more important too. More low end torque wouldn’t change your peak torque, but low end torque is more risky too, so I don’t know.

[CSG Mike]

Originally Posted by Calum

I don't follow. The 150 is meant for high revving, where the engine makes the most power, but the 350 makes more power up top? Or do you mean the 350 makes more area under the curve?

The 150 works best on built engines revving higher than stock engines, with headwork to support that higher revving without choking.

The stock engine starts to choke around 7000 rpm; FI, particularly centrifugal with rising boost, masks that.