I have a 90 928 gt, which headers are better Devek 2 or MSDS? Devek wants $950, seems high?
Thanks

 

Apparently the stock s4 manifolds are pretty good.
So unless you are building a stroker, or supercharged beast,
you will not be getting that much benefit. Yes, they increase
power, but not by a huge amount. If you had an old 928,
with the cast iron manifolds, then yes, the headers will help.
But the price for the s4 units seems high, for just a small
increase in power. If you really want that little boost,
then just get the MSDS headers, because they are
cheaper. The Devek level2 headers are much nicer,
and make more power. They are worth the money.
But only if you really need that improved exhaust
flow...

And none of that stuff is Carb legal.
But I've had my headers in CA for 4-5 years, and had no problems with the visual inspection, etc...

 

You seem like a candidate for X-pipes and adjustable fuel regulator.

 

I want to do the fuel RRPR, headers, X pipe and 2.5 exhaust(from Tom). Hopefully this combo will help some. How much???

 

I thought that headers and an Ott X pipe was good for around 30hp, which many have reported to be significant enough to register on the assometer.

I got a quote for a non-Ott/Cloutier x pipe, stainless 2.5 exhaust, install my MSDS headers (which I already have), high flow cats and a muffler for ~$2k. Probably closer $3k if you include purchasing headers plus the RRFPR, less if you plan to eliminate cats.

 

Thats alot of cash Brian. I guess the stainless gets expensive.

 

Stainless is expensive but it will last. Thanks for the info, I have emailed Tom regarding a dual or single 3.5" but I have not tolded price. If you say 30 hp gain I wonder how much gain without Devek or MSDS headers?
Thanks

 

iirc, the msds direct price did not include jethot coating from msds direct, don't think they even offer it (they do offer nickle/other stuff)... when jethot is added to headers & w/shipping the devek stuff is pretty competitive... ck out 928 motorsports for coated msds stuff, it's less than going direct and coating/shipping/paying ca tax too...

1 thing I noticed side by side was that msds has a "dent" to clear the steering shaft, but devek uses a removable primary tube section... IMO it looks a bit more sano... also devek has a smaller collector, I suspect it might fit better underneath... power seems pretty close as both use 1 5/8" primarys, unless you get the 1 7/8" stuff from devek for monster high end juice/tighter fit too... either way, I'd get them jet hotted, to keep them from rusting out/looking ratty, help w/underhood temps at bit...

fwiw, iirc joe fan uses msds on his 500+ rwhp stroker, so they can't be that bad...

devek just painted the steel on my cat/xpipe section... no stainless there... they couldn't do the rest of the exhaust on my old gal, but can do it for yours...(so I'm going custom to finish it up)... stainless does have advantages, but I'm also considering aluminium, steel is decidedly less$$...

 

Stainless in exhaust isn't for lifetime, as usually people think. It doesn't rust, that is right, but stainless is quite hard and stiff and it ages and gets full of cracks. My 15 years old Jag has SS exhaust from factory and it needs replacing now as it is broken from few places (even in the back). Properly coated (in and out) mild steel exhaust is just as good or even better.

 

equal length headers on my 293 at the rear wheels 5 liter part euro was worth about 10hp, and thats MSDS vs equal length. probably 15hp on a stock S4.

keep in mind, we also started with a stock s4 (kind of GTish as far as cams) and got 285 rear wheel hp with only the cats removed. and stock exhaust. with Devek level 2 headers, coding plug, 3.5" exhaust, and MAF screens removed and air box holes made, we got 335hp. now, that is 50hp and you divide out where you think the headers fall, but i bet you they were the dominant mod!

$1000 is cheap for these kind of headers. Heck, the bmw guys spend more for only one header!!!!!

MK

 

Mark
A couple ?? what is a coding plug and whats the advantage of the MAF screen removal (they look like they will flow alot of air?) also do you have a pic of the holes in the airbox? Did you keep the stock airflow tubes? It seems that the limit for 5.0L NA engines is about 350whp (Pappys 89 auto) I guess his extra 15hp came from GT cams(which you probably have) & his valve work?
Brian

 

Mark,
Is that 3.5 dual or single exhaust? What is coding plug and what air box mods?

Thanks to all for the help. I guess devek level 2 headers, Xpipe and single 3.5 exhaust from Tom, RRPR, remove air box and install a ''T" and put a filter in front of the condenser/radiator.

 

couple of what??

the maf screen flows very little air compared to what you may think. early on the "jump jet" was going to use screens to keep "people" from getting sucked in the inlets, when installed, the airplane couldnt even leave the ground!!! the 928 has not one but TWO screens. mine only had one on the first dyno, and it was removed for the second. there is NO reason to have a screen. the filter, if installed correctly, should keep all large things out of the MAF, and of course, from hitting the hot wire. been driving it for 3 years, 20,000miles, 48 race days, and havent had any issues with my MAF. i think thats a pretty good indication!

yes, the holes in the air box are shown on the 928 racer site. plus ive added one more. basically, i used the inlets above the radiator, and fitted them to the air box, feeded from the base of the windshield. stock tubes are pretty bad, with a venturi 1.5" diameter neck down. i use 3" tubing (brake ducting)

pappy got 350 rear wheel??? what else did he do. thats pretty good. (and out of an automatic????? my best was 335 rear wheel or near 400hp flywheel hp. I dont have any valve work (that i know about)

mk

 

I think you only use the X pipe with dual. I have the level 2 headers and the single 3.5" diameter pipe to the rear with a bunch of muffler combos at the end of the system!

mk

whats this about the RRPR and filter???

 

Mark,
I guess it would be a "Y" not an "X" for a single 3.5" exhaust. I want to put the air filter in front of the radiator and I would need to build a Y plenum. The air would go into the normal two air inlets above the radiator and down the stock inlet air tube to the air box. My plan is to remove the air box and build a bended 3" tube that goes into the intake. The bended T would be wrapped in insulation and the air would hopefully be cooler coming in.

Carl Pires