JimMueller

iTrader: (9)

First, I haven't downloaded the pictures yet Mike performed his usual professional install, detailed below. Both collectors each have both a dedicated NBO2 bung and a WBO2 bung.

The previous system was the Grotyohann headers installed in December 2000, and the matching cat'ed y-pipe. The center gap between the driver side primaries had completely blown out so you could look straight out the collector. The are also some dents and rust spots, in addition to the EGR tube breaking off years ago. Y-pipe had one cat's honeycomb start to disintegrate, but not sure which one. The y-pipe had been resting on my aftermarket g-load brace. Physically comparing the new and old passenger header, the Grot collector was maybe 2" longer, but I don't know how the primary lengths compared. Didn't compare the driver header.

The old passenger header fell right out, and it's replacement went right back in. Hmm, it's kind of tight by the...crap, these headers were designed to work with a stock-style starter. I have a Powermaster starter with the positive terminal on the side. This wasn't an issue for the Grots. That didn't give enough room between the K-member and the positive terminal. After a trip to the dealer for a remanufactured OEM starter (anyone want to buy a perfectly good but used high-torque starter!?) that side finished up with just removing the dip stick tube.

The old driver side needed the oil filter removed and the drivetrain pried over a bit to drop out and replace. Nothing else special on that side. We changed the oil anyway since I had recently seafoamed the top end and had the supplies with me.

The cat'ed ARH Y-pipe fit together perfectly. The i-pipe from the used SLP D/D catback had been welded to a 3-bolt flange just in front of the axle, but the i-pipe was rotated wrong, bending down towards the ground instead of bending towards the rear passenger tire. Cut the pipe, rotated the i-pipe and re-welded it, and it looks better than ever. Tail pipes hang a bit low, but that's because I'm missing some exhaust hangers by the muffler. There's about a finger's diameter between the y-pipe and the g-load brace now.

The driver side primaries hang a bit lower than the passenger side, compared to the bottom of the k-member, and the passenger side header is a few inches longer, probably because of how the tubes were routed for fitment. Looking from the side, the primaries definitely give a bit more clearance than the Grots, but the y-pipe on the drivers side still is a tad low to prevent floor banging.

I did a pair of dyno pulls after the install with the cut-out open to compare to the last pull I did a few weeks ago there. Dynojet wideband in the driver side collector both times.These two pulls were almost a full point richer than the last pull before them. The timing and PE tables changed a little bit since then, but not sure why the difference. I logged extensively on the way home, and WOT was 2-5% lean from 2000-6800 with my LM1 in the passenger side WBO2 bung. My cruise region was still +/- 1%, but the higher regions were ~5% lean. I wanted to use the driver side, but the LM1 cord wasn't quite long enough.

The dyno curve was effectively the same, even with the AFR differences, except that it was 5-10TQ higher from 3600-5500 and 5-10HP lower above 5800. Dynojet AFR was <11 up to 3500, about 12 up to 5000, and mid-12's the rest of the way.

The speed bumps in my community didn't seem to be as bothersome now. So, in short, I'm very pleased with the results. Thanks Mike!!

Full-Force

iTrader: (11)

JimMueller

iTrader: (9)

ARH's before install:











Grot's before removal:








I was trying to get some photos showing how much lower they were compared to the k-member, but the camera kept focusing on the k-member. So this is the only decent installed picture I have at the moment. I might be able to take some more pics tomorrow morning.



I'm not sure where that fluid is coming from on the k-member and driver header. We replaced the the PS pump/pulley/lines/rack a few weeks ago, but didn't clean up the previous leaked fluid. Looks like the pinion seal may need service also, but it's only been like 6 months since it was rebuilt.

1badzo

iTrader: (1)

ar headers are very high quality i was impressed.

mnypitZ

iTrader: (19)

Very nice man. Glad to see it coming together.

RedRallyeZ

iTrader: (20)

nice shoes, they seem very broken in

oh and the headers look awesome too, another impressed ARH customer

ChocoTaco369

So you're saying you lost top end power by switching from the Grots to the ARH headers?

Could you by any chance post the before and after dyno graphs? I'm very curious to see the difference.

JimMueller

iTrader: (9)

I didn't grab the dynojet files this time, so all I can give is a photo of the printout. Upon further review, the last Grot dyno was 2 months ago on the same dyno. Spark is 1-2* higher above 4400RPM on the ARH dyno than the Grot dyno. The Grot dyno commanded 13.0 AFR for the whole PE curve, ARH was commanding 12.5 until 5200, then went 13.0 until the end of the table. Also, remember that one Grot cat sort of blew out it's honeycomb, so that might have been giving more flow?

I considered doing a fresh pre-install dyno, but I didn't want to make everything unnecessarily hot to delay the install.

Blue is the Grot's two months ago, red is the ARH's yesterday (Edit: These are both SAE numbers):

JEB99TA

iTrader: (32)

Picked up some good power over the MAC mids (MAC ORY w/ Flowmaster merge collector) I had on it. Mike installed mine, as well ... 1 7/8" primaries w/ catted Y. Which did you have installed > 1 3/4" or 1 7/8" headers?

ChocoTaco369

I doubt it. My guess would be because the Grots are, simply, a superior design for maximum power. I believe the QTP headers are based off of the Grot design, and you can tell just by looking at them that QTP's are a longer header (which is why they're typically a little harder to install). I would bet that the ARH headers are shorter than your Grot headers, which is why they fall off at the higher rpm's. The longer the header, the better they'll scavenge.

Since your old Grots outperformed the new ARH headers, I'd love to see what would happen if you put high velocity merge collectors on the Grots.

I'd LOVE to see an ARH vs. QTP dyno on a stock tune with nothing but a header swap. If I ever win the lottery, I'm doing this

I'm disappointed that a $900 header got outperformed by one of the first LT's ever designed for the LS1 F-body Of course, the biggest thing that counts is that you're happy with them. Perhaps if you get a dynotune, it'll make up for the difference in power.

JEB99TA

iTrader: (32)

Yep, Grots and QTP's are supposed to be about the best from what everyone says. I don't have any experience with either.

The graph above cuts off the left side of the dyno sheet and only says Horsepower. Can you post up the individual SAE corrected horsepower of each individual graph? The temp, dew point, humidity, barometric pressure/sea level pressure were all slighly different on those two days, as shown below.

IMHO, this is the only way you could make a completely fair comparison between the Grotyhana's and the ARH's. I would think if the Grot's gained higher up top with longer merge collectors, the ARH's should scavenge better down lower than they did with the shorter merge collectors. The ARH's should have shown a stronger takeoff - low range.

The A/F on the ARH run appears to be about .03-.04 richer than the Grot run. Wouldn't all these factors have produced less power, yesterday, if everything was equal for the car on both given days?

If you could confirm Run 023 and Run 024 from the dyno sheet BOTH are SAE corrected numbers, I believe it would further confirm your comparison. Thanks.

Grifter

iTrader: (12)

Those ARH's look great.

I bought my car with Grot's, glad to know that they're a well performing header. How many miles did you put on your Grot's and were they ceramic coated? My car only has 16K but they've been on the car about 5 years and don't look too bad besides some surface rust.

ChocoTaco369

Well, to compare the two directly:

QTP:


ARH:


It's pretty obvious the QTP is a lot longer, and since, I believe, the QTP's are the closest example to Grot's on the market today, it should be obvious why the Grot's outperformed the ARH. If Grots outperformed ARH, I would imagine QTP's would dominate them since they are based on the same design AND have high velocity merge collectors.

This is getting interesting. I'd love to see a dyno comparison of each.

Like Jeb said, do you have SAE corrected numbers for both the Grots and the ARH? This is a great thread because it's one of the first I've ever seen that compare the new ARH headers to other competitors. I'm having trouble justifying the extra $200+ for a set of ARH's that are outperformed by cheaper headers. I imagine the ARH's would fit better than QTP's because of the shorter design, but is it worth it? That's the question.

Grifter

iTrader: (12)

So it looks like QTP's are the cloest replacement to Grot's in terms of size and design. They might be a perfect replacement to my Grot's when they really start rusting out.

JimMueller

iTrader: (9)

The dyno graph shown above is the SAE corrected numbers. I zoomed in to try to make the graph more readable. Jack, maybe you had a typo by saying .03-.04 richer... it's at least .3 richer in the upper RPM's, and practically a full point richer from 2500 to 4500 except between 3600-4000 where it's less.

The second paragraph in my original post indicates the Grot collector was maybe 2" longer when layed on top of one another, but I didn't actually use a measuring tape to determine if the effective tube length was any different.

Mileage on those Grots? Hmm, I have 121K now, and they were installed 27 months after I bought the car. I'd hazard a guess of 90K miles, mostly in Florida, but maybe 15K of that on out of state road trips. The headers were coated by Airborne Coatings up near where Roger Grotyohann lived, I don't recall what type of coating it was.

Here are some installed photos from today...it's already obvious where the low spots are!

JEB99TA

iTrader: (32)

Yeah Jim, def a typo ... meant .3-.4 richer. They look real nice ... glad you got to toss a set on your car. Mine made a lot of power over the MAC's with ORY and FM merge collector mod. My MAC's were well proted, before I put them on and saw 25RWHP/17RWTQ with the 1 7/8" ARH's with catted Y.

Anyway, thanks for clarifying about the SAE numbers. So all-in-all, it looks like the 1 3/4" Grot's and the 1 3/4" ARH's perform about the same over the entire RPM range ... just shine in different places. I wonder how back-to-back testing (with all equal) the 1 7/8" primaries would stack up? They woke mine up and even Mike was surprised at the gains.

Here's mine ... went over some pretty high speed bumps and still have not scraped. hard to believe the 1 7?7" with cats tuck up as well as they did. I'm not lowered.

Bill00Formula

iTrader: (4)

When I first read this I was kind of concerned since I will be doing the same thing (grotts to ARH) but after I thought about it seems like the cats are a very big variable. I am going from 1 3/4 to 1 7/8 probably w/ a new motor.

99mongooSS

iTrader: (4)

nice. nice.

JimMueller

iTrader: (9)

I prefer not to measure at the fender due to stacked tolerances, but to compare, my front fender is 25.75" from the ground and the rear is 26.5". I originally wanted 1.75 -> 1.875 stepped headers, but Nick told Mike it wasn't worth it on the stock displacement, so I decided against it. Oh, and someone commented on the shoes. Yeah, those are the beater shoes whenever I'm working on the car ... they're not quite as old as the Grots

JEB99TA

iTrader: (32)

ARH cats are 200 hundred holes per inch vs 300 holes per inch for most aftermarket "high-flo" bullets, so, there's not a lot of restriction there. I did the cats mainly because I wanted the deep, throaty, yet somewhat muffled exhaust tone. Plus, it doesn't hurt if you get pulled over for being too loud and the LEO does a visual.