Question about stock exhaust manifolds.

[FriboRage]

"In an effort to put out the best possible PEMs we've researched and hit a wall. The problem lies in the front header piece. Opening the inlet as people are isn't doing anything because the inlets are already 1.53" (as big as the port in the head). The problem is the lower section of the manifold. It's 2" OD and 1.63" ID. At that section you're sharing with the other ports.Trying to exhaust all 3 front cylinders out of a single 1 5/8" pipe is crazy. It's no wonder so many people pop front pistons and have questionable gains from other PEMs on the market."

Taken from ZZP's Power Log page.

My question is... is it actually dangerous to run my engine hard on the stock front exhaust manifold? What do they mean by people popping front pistons?

Am I endangering my engine by running 4k or 5k rpms on the stock front exhaust manifold? Do I increase the danger by putting an intake in, increasing incoming air flow?

One of the benefits listed is "Keep the front bank of pistons safer"
Is this only an issue for more modded setups? Im stock atm, intake would be my only mod.

Just trying to decide if I should do my intake now, or wait until I have the power log to install to keep it safe, cause needless to say Im probably gunna run it hard for the first few days after I put my intake on, lol.

[BillBoost37]

I have a lot of issues with the info ZZP puts up about products etc. Biggest issue is most of it's old and partially incorrect if not totally incorrect. Currently they still have a thing up about buy our pcm and a 3.4 and you'll be super fast. Well.. we all know that's not a good setup.

On the exhaust. Maybe the hole in the manifold right at the head is the size they say, but ... with your engine completely cold, reach down and put your fingers around the inside of one of the runners on the front manifold. Feel where it necks down and seems too small? That's the restrictive area, not the opening.

I went through all the exhaust setups on my Bonne that basically apply to the 3800. Here's a pic of some PEM's next to stock manifold for the front. It's tough to see the necking issue I mention, there was material welded onto the pem to help increase that area's flow.


Downpipe, well we know the U bend is a restriction, how about the overall diameter thought? The stock downpipes are double walled. Stock vs a Hogan DP.


GM designed your car to run the way you currently have it and overall you shouldn't have issues from it. Anything is possible and hopefully this exhaust info helps you. And let's not forget that while priced pretty high the Plog is a nice product up until it cracks and needs to be rewelded. Like many products on the market, you should probably consider having it fixed right out of the box. Then you can install it once.

[FriboRage]

Alright, as I was writing that I was thinking of the possibility that it was just marketing, if not anything else..

I just wanted to be sure I wasnt going to cause any damage by increasing airflow to the engine with an intake, and then not improving the front exhaust which is already a restriction zone... so I guess I wont worry about that too much...

Is my 08 downpipe double walled like that? I know that 04+ doesnt have the ubend like earlier GP's do, but I didnt know it was also such a narrow pipe... that looks insanely tight compared to the Hogan one.

[Bio248]

it is not double walled like the stocke one.

[FriboRage]

So my stock downpipe isnt double walled like earlier models?

or the Hogan one isnt double walled? I know the Hogan one isnt, just sayin what a big difference it is

[Bio248]

oops, sorry i ASSumed. i think yours is still double walled and crappy from the factory, just no u-bend.

[BillBoost37]

Likely it's double walled. Reason they do that is to cut down on exhaust noise.

[apierce1289]

I have a lot of issues with the info ZZP puts up about products etc. Biggest issue is most of it's old and partially incorrect if not totally incorrect. Currently they still have a thing up about buy our pcm and a 3.4 and you'll be super fast. Well.. we all know that's not a good setup.

On the exhaust. Maybe the hole in the manifold right at the head is the size they say, but ... with your engine completely cold, reach down and put your fingers around the inside of one of the runners on the front manifold. Feel where it necks down and seems too small? That's the restrictive area, not theyu opening.

I went through all the exhaust setups on my Bonne that basically apply to the 3800. Here's a pic of some PEM's next to stock manifold for the front. It's tough to see the necking issue I mention, there was material welded onto the pem to help increase that area's flow.


Downpipe, well we know the U bend is a restriction, how about the overall diameter thought? The stock downpipes are double walled. Stock vs a Hogan DP.


GM designed your car to run the way you currently have it and overall you shouldn't have issues from it. Anything is possible and hopefully this exhaust info helps you. And let's not forget that while priced pretty high the Plog is a nice product up until it cracks and needs to be rewelded. Like many products on the market, you should probably consider having it fixed right out of the box. Then you can install it once.

Will I need to have anything on my speed daddy headers fixed?

[01gpgt01]

No, Unless you want to rework the down pipe because it hangs down. Heres a pic of the bottom of my car where you can see how it hangs down. The flex also ticks from them.

[apierce1289]

What do you mean it ticks? Also what differences have you noticed from the speed daddy headers?

[01gpgt01]

It ticks because its a single wall flex and leaks

[apierce1289]

Where can I get a better flex pipe?

[01gpgt01]

zzp has one in there exhaust section

[Bio248]

or any parts store...the one zzp sells isnt that special...

[BillBoost37]

There are three or four things to consider when putting Speed Daddies on a W body.

1. O2 extension harness
2. Front O2 will hit the tunnel side.
3. Clamps, get the band type torca clamps from Frozen Boost
4. Install tips, no rtv and lower subframe.