Infinity Design Equal Length Long Tubular Headers Review
Apologies for being MIA recently. Been meaning to post up my review of the Infinity Design Equal Length Long Tubular Headers (original introductory thread posted by
@InfinityDesignhere), but I've been quite busy lately.
For some background info, this is my third aftermarket header setup. I started off with the Evolve Race-R headers (stock header manifolds, but with the vband for swapping in/out straight pipes for primary cats. aka primary cat delete), then moved onto the Evolve Long Tubular Headers, and now finally the Infinity Design Equal Length Long Tubular Headers. I've always been one who wanted to try the newest mods if I believed that they would benefit my car's performance/driveability.
Onto my review...apologies for the iPhone quality photos. Didn't have time to get better photos taken.
The Infinity Design Equal Length Long Tubular Headers truly are a work of art and a masterpiece. Finally, an aftermarket equal length long tubular header option is available for the E60 M5 market. Just by inspection, one can tell that the ID headers are of quality build. The welds are solid and clean, although they aren't the "prettiest" welds I have seen. The finish of the pipes also weren't polished so they had more of a raw look. However, the headers go under the car out of sight so does it really matter how pretty the headers look? As long as they are of quality construction then that's what matters. I had my ID headers ceramic coated, which made the headers all shiny anyways. ID has told me that future batches will look cleaner/prettier as they will polish them before they ship out. I personally don't mind the raw look (plus I got mine ceramic coated so it didn't matter).
After ceramic coating
The install, according to my shop, was a little painful, which is to be expected given the larger headers. The installer had to remove the steering rack heat shield and also exchange the driver side steering knuckle clamping bolt to a bolt with a shallower head. Tight fitment, but with some finesse it works.
One of the things that make the E6x M5/M6 so desirable is the F1 inspired V10 exhaust scream. This is due to the equal length pipes in the header manifolds. With my Evolve LTH, that equal length requirement was lost as the pipes were of different lengths.
Evolve LTH unequal pipe lengths
Because of this, the pulses from the exhaust hit the collector at different times and one can easily hear these uneven pulses when driving. Many think that the Evolve LTH sound like a V8. I personally think it still sounds like a V10, but it's like the Lambo vs R8 V10 sounds (Evolve LTH being the R8 in this analogy). The ID headers, even with the larger-than-stock pipe diameter and longer piping, is able to achieve the equal length piping requirement to get that high pitched scream. Looking at the piping, I could see that the ID pipes were really close to equal length. Unlike when looking at my Evolve LTH piping where it's very obvious that some pipes are shorter/longer than others.
The sound of my exhaust setup with the ID headers is so intoxicating. The V10 Lambo-like scream is back and sounds meaner than ever. Pulses hitting the collectors evenly again. Not only the sound, but the performance. The power delivery is more instantaneous and responsive. Throttle response is more aggressive and the lower end torque (< 4000RPM) has improved by a lot. No more sluggish lag like before. The E6x M5/M6 platform lacks in lower end torque, but with the ID headers the car just picks up and goes. Compared to my previous setups, the power band from 5000 to 8000 seems a little better with the ID headers where the car pulls harder, but it's definitely the lower end RPMs which have a noticeable difference in performance.
Video of some highway pulls with ID Headers
I know that many people are wondering about the dyno numbers for the ID headers.
Many of you know that I'm not about the dyno numbers and I'm more about real world performance. It seems like the modding community is split up into two groups - ones who play the numbers game and only care about getting high numbers on a piece of paper and then those who care more about how the car performs on the road . I'm of the latter group. I respect that people can get high dyno numbers and there is definitely merit to dynoing one's car before/after modding, but if you one gets really high numbers and can't put down that power on the road then what's the point? I've beaten multiple cars who claim to have had higher dyno numbers than me. I will often take my car to Shift S3ctor 1/2 Mile race events and also race friends in Mexico to see what the actual road performance of my car is. I prefer using that as my performance measure rather than a piece of paper with some curvy lines and numbers.
Given that, I still did take my car to the same dyno that I went to before where I dynoed about 500whp/340wtq with the Evolve LTH setup. Ambient temp was about the same at mid-60s F. My car dynoed about 475whp/340wtq consistently.
However, FWIW, there was also a Troy Jeup 6.0L stroker there the same day. The owner had also previously dyno'ed at the same dyno with just the 6.0L stroker and he dynoed about 540whp/425wtq at the time. The day I dyno'ed my ID headers his stroker (after adding some modifications like ported heads, 12.5:1 higher compression, meth, Supersprint LTH) dynoed 500whp/393wtq. So both of us lost power on the dyno that day after adding modifications to our cars which should've added power.
Was it the dyno acting weird that day? Maybe. Did both of our cars need additional tuning for our added mods? Likely. I also didn't reset adaptations prior to dynoing so that may make a difference.
In any case, I am not disappointed at all in the numbers I dynoed because frankly, I don't care much for them. On the road I love the performance of the new headers more and multiple friends who have driven my car before and after say it definitely feels faster. Don't think it lost power compared to my previous setup. I will find the chance to race some friends I had raced before and go to Shift S3ctor to see how the new setup performs, since real world performance is my baseline.
If you're interested in the ID Headers, they can be purchased from Fast Attack Motorsports here. I highly recommend them. Hands down my favorite header setup yet.
Nice update. Correct me if I'm wrong, but the S85 is an odd-firing engine so equal-length runners doesn't mean pulses arrive at the collector in an evenly spaced manner.
About the dyno runs, can you post before and after charts? From the sounds of it, area under the torque curve should be higher, specially in the low RPMs.
Take the dyno graph of the ID Headers with a grain of salt. I mentioned that on that day, both my car and the 6.0L stroker lost significant power after doing upgrades to our cars which should've added power (on the same dyno). Hence, why we are questioning if the dyno was operating properly that day.
I overlaid the ID Headers and Evolve LTH dyno graphs over each other. Run_005 is the ID Headers and Run_003 is the Evolve LTH.
I'm going to get a good datalog of some WOT highway pulls with the ID Headers one of these nights and post up that data along with my old Evolve LTH datalogs. I know a lot of people want to see those.
Would like to see the following comparisons when someone installs these:
Dyno - stock car
Dyno - just tune for stock hardware setup
Dyno - headers and appropriate tune
Would be very interesting to see how the gains are split between the tune and the headers.
I may be able to do this in a few weeks. Have a customer coming in for bearings, header install, and tune. I can do pulls on all on a local DynaPack. It won't show anything for useful comparison numbers to anyone else's setup, but hub dynos are dead accurate and will reflect true gains.
I've attached the BMWLogger datalog files in a .zip in this post. You can download the software and view the datalogs for free. I've also included the extracted csv files.
Here are the datalogs after plotting them to datazap. Note that the extracted csv files don't extract all the info, but it does plot info like ignition timing, RPM, speed, lambda, IATs, fuel pulse width, etc.
Typically, I do 3rd gear pulls when I datalog. Sometimes I go from 3rd all the way through 5th if I have room (as you can see in the Evolve LTH datalog). I always do the same stretch of highway when I datalog to try to keep things apples-to-apples. For the two datalogs I've included, the ambient temperature of the Evolve log was about 56F and the ID was about 65F, but the IATs for both logs were about high 60s/low 70s.