Engine/Transmission (1994 - 1998) Manifold shrinkage + ATS install

[GrantP]

Last month I finally replaced the original exhaust manifold on my '97. The manifold had shrunk to the point that the #1 cylinder exhaust gasket was leaking. The #1 gasket was deformed around the bolt holes showing just how much the manifold can shrink (pic below) When I removed the manifold, the bolts were rubbing very hard against the side of the manifold. There would have been no way to actually thread those back in if I had to re-install the old manifold.



I bought the ATS manifold from Geno's which came with new gaskets. The only additional item I needed for the job was a can of PB blaster to remove the turbo mounting studs from the original manifold (soak them good, give it time, they will come out). I didn't bother removing the turbo for the install, I left the oil line and exhaust attached to the turbo and just moved it aside but it was a tight fit.



Here's where I went wrong, if you're about to do this job, do yourself a favor and lay the new manifold on top of the old one and make sure the bolt holes line up. It's a LOT easier to do on the workbench than it is on the engine! I probably wasted an hour trying to whack the manifold with a rubber mallet to get the joints lined up with the bolt holes in the head. Other than that the install went smoothly, no broken bolts, no bloodshed.



I am not impressed with the mounting hardware from ATS, about 1/2 of the split washers in the kit didn't even fit the bolts (too small) and I'm not a big fan of the allen heads since it makes access difficult in some spots. There is a boss to mount the heater core hose support in the manifold, but they left out the mount for the AT cooler line. Maybe I'm just being picky.



I've had the new manifold on for a month and I've noticed two things since. Gas mileage is up and boost & EGT's are down. I don't have exact readings on the mileage yet since I haven't burned a full tank with the new manifold but I already have a lot more miles on the first half tank than I normally would. I attribute most of that improvement to fixing the exhaust leak (energy wasted to the atmosphere instead of spinning the turbo). I didn't expect the boost to go down but it makes sense if the airflow is really that much better in the ATS manifold vs. the OEM. At highway cruise speeds boost is down about 2 psi and EGT's down ~100 running empty. I haven't noticed any difference in power. All in all I'm satisfied with the purchase and I'm eager to see the MPG improvement over the leaky stock manifold.



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[hdm48]

I think you'll find the reason for the drop in boost while cruising is because the engine is working less to maintain the speed. As in, ALL of the cylinders are now supplying drive pressure to the turbo rather than just a few. A small leak can go a long way to disrupt the pressure in the manifold because now two cylinders must compensate for the loss of up to 1/3rd of the drive pressure, plus the influx of cold air from the leak when the exhaust pulse is no longer present, hence the the increase of EGT's. Pulse manifolds are great as long as all cylinders are doing their part and it is sealed. It's kinda like a three man canoe and one is not rowing, the other two must work harder to maintain the same speed.

Some will expect an increase in power with the addition of these aftermarket manifolds, and some, rarely, do. But this increase is simply because their old unit was leaking so bad they had to use a lot more throttle to maintain speed. With the addition of a new mainifold their engine is now working as designed. There was no increase in total fuel flow, just an increase in function. But where you will really notice the change is when you're towing. Lower temps=more useable power.



I do a lot of porting on these and stock manifolds and in my humble opinion the ATS is the better of the aftermarket designs.



One thing I totally agree with you on. The suppied mounting hardware. What I have found to be a one time, headache free, mounting solution. Find yourself a set of 24valve spacers and bolts and use them. You will need to replace the two center/top bolts with studs. Install them, torque them down, and drive away. This will give you the proper stretch in the bolts. The short allen bolts supplied cannot stretch and you will find yourself performing a re-torque every once in a while. I have seen many short bolts litterally fall out.



You made a very good investment. That manifold will out live the truck.



Sorry for the long rant.

 

[GrantP]

hdb48 - Thanks for the tip on the mounting hardware. I suspect I'll be replacing the existing hardware within the year. Too bad stage8 doesn't have a kit for this.

As for the mileage, I got all excited over nothing. I'm still right around 15 mpg city (uncorrected for 35" tires), right where I've always been. Oh well, given the circumstances I'd still make the purchase again.

 

[CCiatteo]

Thanks for sharing the info. I was always skeptical of the need to do this upgrade. Wasn't sure how much of it was a scare tactic/marketing hype, but that is proof positive. I am guessing you soaked all the bolts manifold bolts going into the head as well? That would be the scary part for me.

 

[JMcCoy]

I also did a lot of porting to the manifold. I removed large pockets of material from the corners. Not deburing, but large amounts of material removal. Hdm48 stated the ATS is a better casting than the other aftermarket manifolds. I have no experience with the others, but I do know the ATS has a lot of room for flow improvement. The main difference I noticed, was the turbo would spool up quicker. also notied a slight increase in power. I figured it was due to the turbo spooling up sooner. It could always just be in my head. After all, my truck runs better after an oil change. LOL! I am very happy with the upgrade. I would recommend it to anyone.



I could not believe ATS made me reuse the old turbo studs and nuts. The old two nuts locked together on the stud trick pulled the stud right out. That is if you didn't destroy the nuts during turbo removal. X2 on soaking the nuts and bolts with penetrator. Good luck.

 

[GrantP]

I've done a lot of driving this week and had to fill up again, 18. 0 mpg this time. I finally had a chance to really push the truck driving up I-17 from Phoenix to Flagstaff. I couldn't get the EGT's to hit 1200 coming up the hills. Maintaining 80 mph up the hills was no problem, that's a HUGE improvement over the past when I had to constantly back off the throttle as EGT's were easily hitting 1250. Don't ignore cracked/leaking exhaust manifolds!

 

[Hammer]

I have one on my truck and just because you went with a ATS does NOT mean it will not crack. The one on my truck is the 2nd manifold as the first one cracked apart at the center bell and the back cylinders fell off when we changed them out.



It was not warrantied and quite frankly the rusted finish was terrible with the factory coating having been long gone. The one thats on the truck now is also rusting bad outside and the finish is CRAP for the amount of money you spend on them. I will not buy another one from them with how poor their qiuality is.

 

[hdm48]

Hammer,

Just out of curiosity, what have your temps been like in order to crack a three piece manifold?

As a side note, 2 things



1. After market manifolds do not come with any kind of coating as a rule. I glass bead and coat with POR.



2. No matter what manifold a person runs, if it cools too quickly,(IE:chopping the throttle after a long pull and going down the other side) any manifold can and will crack.



Being an old trucker, going "over the top" easy is manditory for component life. It lets things cool down.

 

[Hammer]

hdm48...

I am a street truck that does not see a long extreme temp swing. With that what I mean is no sustained high temps like one would see towing up a steep percentage grade. I do see some temps when dyno but those temps are not extreme enough to warrant the manifold cracking apart.



Your correct on the coating and ATS would be far better off to NOT coat them then to put the crap on they are trying to pass off as a temp coating. That being said,the coating should not have come off like it has in less than 2 months from the date of the install.



Being a trucker I am in firm belief that my truck does not see the extremes that a class 8 truck would so there should have been NO REASON for one of their manifolds to crack apart. I can also say that I have seen the ATS manifolds being used in pullers trucks with no issues of cracking and their temps are far more extreme than mine.



Again,their quality control is horrible and their customer service is worse and it has lead me to venture down other avenues.

 

[hdm48]

Interesting. Well, as happened before, posting warranty issues on sites such as this one will lead them to adjust their policys.



Since there is no real reason for the manifold to crack, have you considered using a BD manifold. They don't flow as well, (non-ported) but they do have a different center section.

I have seen a couple crack, but they are from sled pullers and have had a waste gate plumbed into it compromising its strength.



as I said, interesting.

 

[Hammer]

I am actually waiting for the release of the stainless steel manifold for my 12v so I can rid myself of the ATS. I have a good friend of mine who did one on his 24v and its really a nice piece both in looks and fitment.

 

[MLee]

Have you guys heard of "Diesel power source" I seen their three piece on the internet last fall on E-bay and followed through where they were located, and the main guy is located five miles from me. So I bought local, and have used it for a couple months now and just returned from a trip of 2500 miles, have'nt done a recheck on the torque for the second time yet, but it preformed as expected. I figure that I'm close to 20K CGVW, with trailer, and compared to those that I went with that grossed maybe 16-18k with his D/A 2008 I bettered HIS milage of 11. 2 by 13. 0 and my 5 speed, always put in less fuel, even by toping to the brim of the pipe. Needless to say, he did not have much to say.

If you want more info on this three piece manifolds, price etc send me a PM.

Disclaimer--I am not associated with this business in any way just a satisfied customer.



ps:

His manifolds are preassemled and pressure tested and have a coating that will with stand 2200* and are drilled for a pressure tap and pyro.

 

[SLangone]

How do you all feel about HTT products? CEM112 the lowest price I have seen was on ebay for 435. 00 with free shipping.

 

[GrantP]

Thanks for sharing the info. I was always skeptical of the need to do this upgrade. Wasn't sure how much of it was a scare tactic/marketing hype, but that is proof positive. I am guessing you soaked all the bolts manifold bolts going into the head as well? That would be the scary part for me.

I did spray the bolts about an hour before loosening them but I don't really think it had any effect. It would be very hard to actually get the PB blaster to the threads with the manifold installed. I was afraid of snapping one of the bolts during the removal process; thankfully the factory fasteners are very high quality and didn't give me any grief. Can't say as much for the hardware that came with the new manifold.

 

[GrantP]

Since these "product reviews" are rarely followed up on, I thought I'd post an update for anyone who cares... 18 months later the finish on the ATS manifold looks like the day I installed it. There is some very light surface rust on the mounting bolts. No leaks, no cracks (not that I expected any), no loose bolts, no problems.