So ZZPerformance.com sells a downpipe. The Stainless Steel version sells for about $160 I think, plus $25 or so to have it installed. A lot of people tell me the downpipe gives you no real HP or torque boost. Is that true? Nothing to be gained by it unless you're running a turbo or supercharger? Also, one guy said it gave his car a deeper tone, would that also be likely?

 

i personally don't have a dp but i have heard good things about them. they increase air flow dramatically which translates into better get up and go. this topic has been covered several times on this forum so i would suggest using the search function and reading all the opinions that have already been offered. there are TONS of threads so i don't thing you'll have trouble finding it. if you still have ?'s after that, then we will be more than willing to answer them.

 

Get it.

Not everything is going to give you a seat in the pants feel, HOWEVER, it's a supporting mod. Because it's a supporting mod, it means that when you put other modifications that help your engine breathe, that's where the potential is at. After it breathes in all the air, you need to exhaust it well, and a Downpipe does that. To get the full potential from future mods, you'll need a downpipe.

Change in tone.. MAYBE. I couldn't tell on my car any noise differences, nor could I FEEL any differences, but I know now that in a couple weeks when I put on 3 more engine mods and get my tune, they'll all work to their full capacity.

 

Thats true of many mods on the NA L36. The stock intake and exhaust aren't really overly restrictive for an L36, so the resulting power gains by opening them up is minimal. Its just like doing a big catback, or putting on ported manifolds, or a big intake- you'll gain a little power, just usually nowhere near what the L67's do.

The reason the L67s make so much larger gains, is in factory condition they are more restricted (use the same downpipe and manifolds as the NA version)- and they can get rid of some mild factory knock (just due to age and such)- so they gain more timing back. If they get their knock to 0, they drop pulley size on the supercharger to flow more air. Since you can't make a minor change to dramatically increase airflow on an L36- you're stuck at the same level. Thats why power gains are usually so much better on L67 setups.


A little, especially if you delete the cat. Its not a night and day difference, its pretty mild- nothing like replacing a muffler; but if you listen closely back to back, you can tell.

 

Downpipes are great mods. I've always heard that a 2.5" downpipe is a better option for N/A 3800s and the 3" (what I have on my GSE) is a better choice for L67 cars.

ZZP's pieces are excellent quality and I highly recommend them.

 

My 2.5" 304 Stainless Steel bolt in with Cat and supporting Gaskets total was about $260

just an FYI. But completely worth it.

 

[QUOTE=chibiblacksheep;150083]My 2.5" 304 Stainless Steel bolt in with Cat and supporting Gaskets total was about $260

I've been eyeing a downpipe for awhile, but would it be completely necassary to go with the 304 stainless steel. I live in MN so with winters i would be replacing the gaskets no doubt about it but is the 304 worth the extra money?

 

Be prepared to get your PCM tuned cause most likely you will throw a code P0420. It's not going to hurt anything, but if you want to pass your states emissions test you need to get that code erased.

 

i'd say anywhere there is heavy rain, snow, and salt 304 is a best buy. just a heads up, last year in november is when i got my downpipe because zzp does a "black friday" sale after thanksgiving. i ended up getting my 2.5" bolt in w/ hi flow cat for a steal. suggestion: save up all your cash and buy then. i think i spent about 600 last year for about 1100 worth of stuff.

 

I suspect this is a bot account as it keeps bumping old threads, talking about unrelated stuff, and adding suspicious links to external sites.

But if anyone else is curious - there are no downpipes for w bodies anymore with a built in dump. The downpipe on these cars is mostly pre-cat, so any kind of dump would also be pre-cat / attract unwanted attention from the EPA.