dieselcarpenter

I am wondering if anybody is using a newer 3 piece exhaust manifold on their 1st gens? If so what brand? And what does it do as far as performance? I have heard that the stock manifold is prone to cracking, how worried should I be.Does having a 3pc affect EGT? I am also curious to hear what people have done about the intake. I have found arched intakes for the 94's and later (arc, banks etc..) anything for our trucks? or are they interchangable? How different are the 89-93's from the 94-98 12v's? (if you can get a shoe to fit wear it, right?)

marksmith

I have a htt 3 piece manifold. I LIKE it.

As for head design... the exhaust manifolds are the same from 89-98.

I haven't had my hands on an ATS manifold.. but the HTT manifold runs a SHORT taper into round passages. Kinda making a bottleneck that I didn't care too much for (nothing a die grinder wont take care of)

The rest is great. Fit/finish are good. Came pre tapped for the pyro. Nice and heavy where it counts. Has the tapped spot for the heater hoses.

EGT's are down a little... but not a TON. Spool-up is DEFINATELY better (even with the bottleneck coming right out of the head) Cool-down is most definately better also. Takes about 30-45 seconds to drop to 250-300 (yeah. I need more fuel) Before it took about 1.5-2 minutes. (post turbo measurements)

90firstgen

I have an ATS manifold sitting on my floor. Its huge compared to my shrunk stocker. And very heavy I might add. The quality looks very good and I guarantee it will flow double than what mine looks like right now.

BC847

I got one of the earlier ATS manifolds and was very surprised to find the manifold inlets, just inside past the flanges VERY rough and irregular. Quite jagged in fact.

I ended up grinding it all as it should be. I get the impression such is no longer the case.

I also run the Banks TwinRam intake-horn and find it helps a LOT in balancing the charge-air to all the cylinders. (It is a custom install, NOT off-the-shelf). To date, I can't bog the engine running two Snow .625 nozzles from a maxed 220psig pump into the intake-horn. It seems others can bog their mess fairly easily with the same set-up in the common single intake-horn.

As far as the single type intake horns, many have very good results simply fabricating a fat pipe directly to the appropriate mounting plate bypassing the expensive store-bought models.



Either way, as part of a system where all components are considered when cyphering total engine volumetric efficiency, both manifolds contribute favorably.

90firstgen

Well I installed my ATS manifold this weekend. I was pretty worried about the old bolts breaking off in the head but after plenty of PB and Howe's penetrating oil, they came right out very easily. I was thoroughly impressed. They were pretty bent to say the least. It was a very easy install except for tightening the two top bolts by the collector. Had to grind down an allen wrench to finish them up.
I really can't feel any difference in maximum power but I can definately say that it widened my powerband. It takes less pedal to get places. I'm very pleased with it but if you're thinking about doing this just for a performance mod, spend your money elsewhere. The only reason I did it was bacause I didn't want to replace a broken head. BTW, it looks really sweet Cheers

EDIT: I may have a possible boost leak now to my crossover. I'll report back about maximum power when I'm sure that its fixed

leper

I put the ATS manifold on at the same time as my 16cm housing. Big difference in off the line acceleration, and really anytime I stomp it. I started with the 18.5, not the 21 and still noticed a difference. Tows 10K# alot better now also.

On the top two bolts.... I took a socket that had the 8mm allen in it and knocked the allen part out. I ground about a third of it off and put a gearwrench on the stub. It worked really well.

rbrettctd

So what kind of egt drops are yall seeing?

90firstgen

I haven't noticed a drop on normal driving around town, but I didn't look at the pyro during WOT runs. I'll report back tonight

RamW350 dually

I had a question about the 94-98.5 ATS exhaust manifold. If you buy it for the 2nd GEN 12 valve, when you go to bolt it up to the 1st GEN 12 valve what will you have to do for mounting the heater pipe that runs above the stock exhaust manifold? Does the above ATS manifold come with a place to bolt the heater pipe exactly in the same spot it's structurally mounted on the stock exhaust manifold? If so I'd like to consider buying one for our truck, as a 3 piece manifold is superior to anything else. Thanks for any replies.

Salvy

marksmith

The ATS does NOT to my knowledge have the bolt hole.


The HTT manifold has the hole. Bolts up exactly like stock.

JAyers

My ATS has a heater tube mounting bracket hole. lol. Its cast right into the manifold. I was told that if you hold a HTT and an ATS side by side that their are no real noticeable differences between the two.

90firstgen

Yep it definately has the mounting hole. Fits like its made specifically for our pickups. Like a glove

cbtumedic

Does the ATS come assembled? Ive heard that they are a pain to put together, and I know the HTT comes assembled.

leper

Mine came assembled. It needed a little bit of adjustment from a hammer and a block of wood, but it was an easy install.

frostie

I installed an ATS manifold about 1 1/2 years ago. I didnt like the shape just inside the ports as someone mentioned earlier, so I ported and polished it as much as possible. I cant give performance or EGT specs because a made many changes all at once. I was fortunate it have a bare head on the floor. So when I assembled the manifold I did it on the head on the floor, it was easy. just bolt the center section up, then heat one end peice and slide it on and put some bolts in before it cools, and do the same with the other end. I never had a stock manifold crack and believe me I have had them hot. I have heard they will. I dont regret buying the manifold but I believe they are more for EGTs than performance.