Hogan Downpipe

SpaceBar wrote:

Almost any autoparts chain (advance or autozone) maybe even sears will scan your car for free and tell you what the code(s) are. Just go in and ask them to scan for you.

Including KR?

Jack the R wrote:

SpaceBar wrote:

Almost any autoparts chain (advance or autozone) maybe even sears will scan your car for free and tell you what the code(s) are. Just go in and ask them to scan for you.

Including KR?

No it only scans for codes.

No downpipe for me today... Like Ben, I also found the nuts and studs on the 4b flange had formed a solid union of rusted steel. PB Blaster had no effect whatsoever. I rounded off a couple nuts and gave up. Now I'm wondering if I should pick up a high-flow cat to take with me to the muffler shop when I stop by to schedule the work. Any recommendations on brand/supplier?

I also examined the front PEM install situation. Didn't have time to try to do it today, but did get the engine lift bracket out of the way at least. Looks like the heat shields will be a PITA to get off, and the dipstick tube is in the way, somewhat. I want to do this before winter too. With a week off in both Sept/Oct, should be able to.

On a brighter note, I now have my 68 ready for a few blasts down the track on Saturday. Cleaned up the oily/grimy undercarriage, slapped on the street slicks for the short drive to the track, aired up the Front Tires, removed the front drums and sprayed out the brakes thoroughly with brake cleaner. I have a fair amount of material on the shoes still, but they are not in very good condition for some reason. Maybe cheapies installed a long time ago. I need to do a 4W brake job next spring before I drive it to NTR in OH in August.

Get the high flow cat with it. The labor costs will be similar.

I wish I got the high-flow cat, but whatever.

It's very likely that i'll be getting a 3in shorty DP to be taken to a shop and welded up to a catless, resonatorless, bent 3in exhaust where i'll probably reattach my current glasspacks to as they are (only with a Y instead of the stock T split).

The reason this is my next mod is because I believe my cat (its the original with 166k on it) is clogged and bad. I have a PO420 code coming up increasingly frequently and the engine chokes up badly at WOT when it reaches high rpm.

A GM tech friend of mine says that they confirm a clogged cat usually by temporarily removing the upstream (on exhaust manifold) O2 sensor, then go WOT and see if that choking goes away. Removing the sensor gives the exhaust an alternate path out and you can then identify that the cat is clogged if it doesnt choke with the O2 out.

I'm going to remove the sensor and see tomorrow morning - noon and then if the cat is bad ill order the DP and prepare for a new exhaust.

I know two of you used the hogan pipe and it looks very nice and I know this territory has probably been covered already but whats the best 3in shorty DP. I remember Aaron talking about the different steels 409 / 304 and such but I couldn't find that thread.

options as I see it:

zzp standard $89
zzp upgraded 304 stainless $114
wbs unknown grade stainless with interlock $109
hogan 409 stainless $124

they all seem to emphasize different parts that are the best...
zzp has their superior stainless steel option
wbs offers the interlock flex
and hogan, i think i like their bend and overall look set up the best so i'm kind of leaning toward it

any more thoughts?

According to my GM shop manual, a clogged cat can be diagnosed by reving the engine in P or N. If the engine revs normally, no problem. If it bogs or hesitates in the upper RPMs, it's likely a clogged cat.

AA wrote:

According to my GM shop manual, a clogged cat can be diagnosed by reving the engine in P or N. If the engine revs normally, no problem. If it bogs or hesitates in the upper RPMs, it's likely a clogged cat.

well i pulled the O2 sensor and drove it. Other than the horrible sound, it made no notable improvement

so what's next...?

i might make a quick vid of the horrible sound while i have it off for s's and g's

can anyone guess what downpipe that is just by looking at it?
I just got it today and the gasket i got through work

GP/Regal?

its the w body store DP with the interlock flex option and it looks just like a hogan to me...

oh yeah, here's the box it was shipped in...

Um, I inquired at W-Body Store when I was shopping for a DP, exactly because theirs looked like a Hogan. They told me it is in fact from Hogan Perf.

there you have it. a hogan for $15 cheaper

im just wondering if this 3" downpipe will fit the RIV, it looks almost exactly like it

http://www.hoganperformance.com/DP8S.htm

Yes, that is correct for your Riv. I have it on my 98 along with their magnaflow cat.

It's a direct bolt on in place of the oem DP, as long as you can actually remove the bolts to the stock cat... they are usually heavily rusted. If you are doing the DP, I'd either get the Magnaflow hi-flo cat to go with it, or eliminate your cat altogether if you can get away with it where you live.

Ive got the Hogan dp its made fine bolted right up , no problems . Overall a nice piece ... good price too

Quick question...

Everyone seems to agree that the Hogan DP8S fits our '97+ Rivi's just fine (if you don't live in the rust-belt.) The only real concern I've seen raised is over the flexible coupling...

So, if the stock pipe doesn't have a flex-joint, why does the aftermarket unit need one?

The stock pipe does have a flex joint. It's hidden inside the upper flange.

Yup.

deekster_caddy wrote:

The stock pipe does have a flex joint. It's hidden inside the upper flange.

Well that explains why I couldn't see it with a mirror and a flashlight (car on the ground.) Is that where the original pipe is restricted? Cuz everything I could see looked pretty fat...

There might be some pictures of the 2.25" diameter stock pipe and the 3" diameter Hogan pipe. Even still, we're only talking .75" difference, but it's a difference you can really FEEL.

The stock pipe crushes down to less than 2.25

May as well ask one other dumb question...

I was looking at the Hogan site, and I can't figure out what the difference is between the 'standard' and 'interlock' flex couplers is. The standard isn't literally just the stainless "weave" by itself, is it?
Thanks again in advance.

Eldo wrote:

I was looking at the Hogan site, and I can't figure out what the difference is between the 'standard' and 'interlock' flex couplers is. The standard isn't literally just the stainless "weave" by itself, is it?
Thanks again in advance.

I can't find the reference to 'standard" and "interlock" on their site !!!!
I've looked at the DP8S that you mentioned.

Edit: DUH, i see it now. I would have to assume that interlock is as you thought, a cross weave design. For the extra few bucks it would be worth it.
And, before you install the pipe assembly, it would be worth your time and a few more dollars to wrap the section of pipe and flex joint with header wrap.
I did my complete header and down pipe before install and have noticed a big difference, compared to others that are un-wrapped, as far as heat transfer and "normal" header noise. On unwrapped systems there is a noticable tinging noise from the pipes themselves and others on this site have mentioned a noise from the flex pipe that they have solved by wrapping, after install. A PITA to do after you've installed the pipe.

I'm not wrapped and have no issue with such a noise from my Hogan DP.