Stock Exhaust vs Stage 1 Exhaust, Dyno Tested Results!

[vwdmc16]

This is a test I have wanted to do from many years and I finally had the time to do after purchasing a lightly used Houston Stage 1 stainless system from fellow member Fox2506 in NC, a few months back. I hope it is educational or atleast entertaining.

The premise of this experiment was to confirm or deny the power levels that could be unlocked from our PRVs with a full exhaust system upgrade, over the years Ive hear many claims about just how much the factory exhaust restricts our engine, claims from 10 to 35hp. To test this I needed one key piece of specialized equipment, a Chassis Dynometer. This plan: dyno my healthy engine on the dyno with three pulls to get an average, remove the factory exhaust and dyno again after the new exhaust is installed. The Dyno im using is a Dynocom 5000 2wd Eddy current style machine. Its very simular in design to Mustang brand dynos which are considered the standard in power measurement int he racing/tuning industry, Speaking of which I have had this very car dynoed on a Mustang 2WD machine and got just slightly lower numbers than this Dynocom {10hp and tq less on the mustang}. The important information we are looking for is the before and after difference in output which is what I got.


The car:

Vin 1768
stock K-jet
Stock internals with 70k+ miles
stock air box and filter, cold air intake tube
MSD blaster2 coil and coil resistor deleted (this mod created a 12hp gain alone on the mustang dyno years ago)
fully stock exhaust
extra 2 degrees in ignition timing
CO adjustment optimized for 12.8:1 AFR




Dyno Time:

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1305_zpsluyqwri6.jpg

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1307_zpsorssg2yk.jpg

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1309_zpsgfn7mnuw.jpg



I used the optical RPM pick up that shoots a light at the crank pulley that has a small reflective sticker on it, the sensor detects the reflection and counts it at one rotation. I ran the car up to 5500rpm as there is no more power past 5200 anyway. Result was an average of 115hp and 141 tq. This is constant with the numbers I got off this machine early last year and again a bit higher than the Mustangs results {105hp/130tq}


http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1310_zpsk89qzj6a.jpg




The New Parts:

<10k mile used all stainless system, I cleaned it up with a media blaster and inspected the cats and muffler for wear, all look to be in great condition.


http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1312_zpszmmasidc.jpg



Out With The Old


http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1332_zpso60w2nfu.jpg

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1313_zpsg5y0kixv.jpg


Tools:

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1314_zpsxck6xaks.jpg

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1315_zpsgyiljqf2.jpg


Another picture of my newly finished Bilsten HD project that I made another thread about


http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1316_zps5b4xlztn.jpg

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1317_zpsbhqk9y2t.jpg



after bit of cleaning, still pretty filthy

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1318_zpso3pz5bqw.jpg





Weight Difference
Another answer I couldnt find was how much lighter is the new system, So here is a ll the old stuff that isnt being reused:

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1321_zpsurpozfbl.jpg (http://s31.photobucket.com/user/vwdmc16/media/Dmc%20exhaust%20mods/IMG_1321_zpsurpozfbl.jpg.html)

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1319_zpsvplxi1o5.jpg


55lbs!!

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1320_zpsos60welp.jpg (http://s31.photobucket.com/user/vwdmc16/media/Dmc%20exhaust%20mods/IMG_1320_zpsos60welp.jpg.html)



All the new stuff

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1322_zpsvn6yr3uu.jpg (http://s31.photobucket.com/user/vwdmc16/media/Dmc%20exhaust%20mods/IMG_1322_zpsvn6yr3uu.jpg.html)


48lbs! a savings of 7lbs, Not much...

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1323_zpskwaxaabl.jpg (http://s31.photobucket.com/user/vwdmc16/media/Dmc%20exhaust%20mods/IMG_1323_zpskwaxaabl.jpg.html)

[vwdmc16]

After cleaing and new gaskets it was time to install, My studs were only a few years of and still very clean, came out easily. The driver side was easy but the right side was a pain even on a lift. With the limited room I had to remove all but two of the manifold studs to get the clearance to get the manifold on the head, also you see the starter/ alternator wires need to be re routed around the front side.

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1324_zps5mr2aofc.jpg (http://s31.photobucket.com/user/vwdmc16/media/Dmc%20exhaust%20mods/IMG_1324_zps5mr2aofc.jpg.html)



Clearance to my tow hooks ( not stock btw) were a bit close but not enough to hit


http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1327_zpsshj8dywa.jpg (http://s31.photobucket.com/user/vwdmc16/media/Dmc%20exhaust%20mods/IMG_1327_zpsshj8dywa.jpg.html)


passenger side is even closer to the frame

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1329_zpsy3rm0uo6.jpg (http://s31.photobucket.com/user/vwdmc16/media/Dmc%20exhaust%20mods/IMG_1329_zpsy3rm0uo6.jpg.html)

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1330_zpsj1npkyeg.jpg (http://s31.photobucket.com/user/vwdmc16/media/Dmc%20exhaust%20mods/IMG_1330_zpsj1npkyeg.jpg.html)


After the headers it was quite easy, easier than installing the stock muffer.

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1331_zpsydewqugr.jpg (http://s31.photobucket.com/user/vwdmc16/media/Dmc%20exhaust%20mods/IMG_1331_zpsydewqugr.jpg.html)

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1326_zpsadjo18i8.jpg (http://s31.photobucket.com/user/vwdmc16/media/Dmc%20exhaust%20mods/IMG_1326_zpsadjo18i8.jpg.html)


Back To The Dyno

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1333_zps00ljpvez.jpg (http://s31.photobucket.com/user/vwdmc16/media/Dmc%20exhaust%20mods/IMG_1333_zps00ljpvez.jpg.html)

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1334_zps4col2pbk.jpg (http://s31.photobucket.com/user/vwdmc16/media/Dmc%20exhaust%20mods/IMG_1334_zps4col2pbk.jpg.html)



Another 4 runs were made with an average of 133hp and 149tq, keeping in mind that a the this dyno measures about 8.5% higher than a Mustang brand we really get a more realistic power of {121.6 hp and 136 tq}

so an increase from 115 to 133hp (18hp) or on a Mustang {105 to 121hp} (16hp)

and an increase of 141 to 149tq (8ftlbs) or on a Mustang {130 to 136tq} (6 lbs)



Conclusion:

This exhaust system does increase power and torque but not nearly the gains that were rumored when measured on this dyno or approximated on another. Full disclosure that there are many variables at play and everyone's results will differ I tried to keep testing conditions as close as possible by measuring before an after all in one day but relative temp barrametric pressure and humidity did change a few degrees as my dyno is not indoors, so take these results as you will, it wasnt the most scientific test but it was something. Also the AFR was slightly leaner than the 12.8 I got during the baseline tests so there could be a bit of power left on the table there. All in all I believe it is a worth while upgrade as the sound is so much better and to me the car's engine note just feels liberated, that makes it a much more enjoyable drive.

Thanks for reading.

[jawn101]

Awesome tests and very interesting results. I can personally attest to the fact that the car feels faster than before (though 1768 has never been a slouch.) More importantly, though, was the responsiveness, feel and sound. Clint's car sounds like they all should have. Great upgrade! Now just to see how the smog goes next year :)

[Jedidentist]

Very nice test and write up. Thanks for sharing!

[DavidProehl]

Great post! The car sounded unbelievable on Saturday. When you and Jon went for a drive the rest of us were just looking at eachother with our jaws on the floor listening to it. That is how the car should sound!

[Dangermouse]

Very interesting, thanks.

I assume that yours is a Manual?

[Trstno1]

Your system looks great!

Question: What did you use to properly clean the exhaust manifold mating surface on the engine block? Also, did you use any RTV sealant in addition to the gaskets in order to create a better seal? I'm guessing not, but thought I might ask. I am about ready to install the same system as yours and just want to get all my ducks in a row prior to starting.

Thanks for the info in adavance! :cheers:

[jamesrguk]

"...so an increase from 115 to 133hp (18hp) or on a Mustang {105 to 121hp} (16hp)"

It's easy to be a bit disappointed with the increase figures, but when you're starting with such low numbers it's probably best to work out the percentage increase.

115bhp to 133bhp is almost 16% increase that's a 7th more power! I'd say that's not bad just for changing an exhaust.

I'm crap at maths so feal free to ridicule as required lol


James

[vwdmc16]

Very interesting, thanks.

I assume that yours is a Manual?

Yes 5 speed

[vwdmc16]

Your system looks great!

Question: What did you use to properly clean the exhaust manifold mating surface on the engine block? Also, did you use any RTV sealant in addition to the gaskets in order to create a better seal? ...s:


I used a small 3m bristle disc on a 90' air sander to get the sealing surface clean. All gaskets dry without rtv

https://www.google.com/search?q=3m+bristle+disc&client=ms-android-att-us&espvd=1&source=univ&tbm=shop&sboxchip=Shopping&sa=X&ei=p7EHVYiiLdDo8AWQ1oLwAg&ved=0CCsQ1TU&biw=360&bih=559&dpr=3#spd=18437156106882989591

[Jonathan]

Out With The Old

http://i31.photobucket.com/albums/c396/vwdmc16/Dmc%20exhaust%20mods/IMG_1313_zpsg5y0kixv.jpg



Nice write-up Wolff.

Question: is there something in place plugging the middle hole (of three) where we normally see the three brass screws (plugs)?

http://store.delorean.com/p-6400-plug.aspx

It's been mentioned recently on another thread when chasing a vacuum leak/idle problem and noticed in this photo that it looks like one of yours isn't there.

[DCUK Martin]

115bhp to 133bhp is almost 16% increase that's a 7th more power! I'd say that's not bad just for changing an exhaust.



But only a 5.6% increase in peak torque, which is more "real world" especially in terms of low gear accelleration...

If you want to be depressed, my diesel Mazda pushes 300ft-lbs

[jamesrguk]

But only a 5.6% increase in peak torque, which is more "real world" especially in terms of low gear accelleration...

If you want to be depressed, my diesel Mazda pushes 300ft-lbs

Martin, there I was, trying to make people feel better with careful reworking of the information to make it sound awesome and you came along and barfed all over it.

Well I hope you're happy :vomit_3:

Even so I don't think you can expect a huge amount more from just an exhaust change.

Happy Birthday BTW.

J

[DrJeff]

... my diesel Mazda pushes 300ft-lbs

And again the question, when is someone going to engine swap a turbo diesel into a DeLorean?

[DCUK Martin]

When someone has a reason to...? I can't think of a good one, but it'd be a 3.0 Jaguar twin turbo V6 if I did...

[vwdmc16]

Nice write-up Wolff.

Question: is there something in place plugging the middle hole (of three) where we normally see the three brass screws (plugs)?

http://store.delorean.com/p-6400-plug.aspx

It's been mentioned recently on another thread when chasing a vacuum leak/idle problem and noticed in this photo that it looks like one of yours isn't there.

Well half of it is there, i was doing a regular nut and bolt check on the car and just barely got the wrench on that bolt and the head came off, the base still seems to seal however.

[vps3922]

MSD blaster2 coil and coil resistor deleted (this mod created a 12hp gain alone on the mustang dyno years ago)


<Raise eyebrow> What is that? Do you have details on it?

Great writeup! Thanks for sharing!

[DMCMW Dave]

MSD blaster2 coil and coil resistor deleted (this mod created a 12hp gain alone on the mustang dyno years ago)


The skeptic in me always has to ask - compared to a fresh stock system, or one with nasty old plugs and wires that the MSD could punch through better?

[DCUK Martin]

I agree with Dave. In my turbo engines, I've stuck with the original setup because it supports a spark even under 15+ psi boost. That's bougicord leads, standard even fire distributor, bp7efvx plugs.

[vwdmc16]

I hear what you are saying, the plugs were copper boschs, bougicords, and bosch capgcap/rotor were less than a year old.

To be honest im skeptical too and when i get time, plan on retesting that experiment on the dyno.

[DCUK Martin]

And the coil, and its and the resistor's connections?

[vwdmc16]

That's true, i think i replaced those during the test. I still have the original coil and resistor at home, ill reinstall them and see what happens again.

[Trstno1]

What did you use to cover the starter and alternator wiring to prevent heat damage from the header?

[vwdmc16]

For now just some silver heat reflective tape, now that i have some spare time im going to reroute the wires and get some nice kevlar heat protection sleeves.

[PJ Grady Inc.]

It's probably there but just headless at this point! It's not uncommon to see where someone overtightens the brass screw/s to the point where it breaks off.
This is either they think it's a "shearbolt" by design (like the ignition lock bolts for example) or because they also lack much of a "head" on thier shoulders as well!

Rob


Nice write-up Wolff.

Question: is there something in place plugging the middle hole (of three) where we normally see the three brass screws (plugs)?

http://store.delorean.com/p-6400-plug.aspx

It's been mentioned recently on another thread when chasing a vacuum leak/idle problem and noticed in this photo that it looks like one of yours isn't there.

[Lou and "Boo"]

Great thread ! I wish I did the same when I changed to headers and open exhaust.
I wonder how much one of those "portable" dynos cost.

[vwdmc16]

We were going to build a trailer rig for this dyno to make it portable but decided against it. They cost around $20-30k new.

[Trstno1]

So I have learned the hard way that you cant install the passenger side header with the exhaust manifold studs already mounted and other items not either disassembled completely or at least loosened.(I should have read your post a little closer). It also appears that it would be much easier to route the starter wires and hook them up prior to fully installing the header. Any thoughts on that?

Does anyone have a pic of how they routed the starter wires around the header? Maybe a view from the top down? Any future issues with the header melting the starter wires?

This passenger side header is really a PIA to install on these stage 1 systems!! Can't wait till its finished!
:wrenchin:

[Trstno1]

Do you happen to have a picture from the top looking down on how you routed your starter wires through or around the header? I am currently installing my stage 1 exhaust and am having issues with the wire run to the starter.

Also, did you install a starter heat shield? If so, what sort of spacers did you use?

Thanks in advance

[rtcraver]

thinking about doing a header setup (from Hervey over the winter w/ Flo's for mufflers. Already have cold air pipe alone and as I said, the Cats have been hollowed out before I got the car. Interested in seeing what difference it will make.... Acctually, ideal set up would be able to find a Peuguet 604 intake manifold and carb it with Holly or Edelbrook... Any manafolds out there for sale??? :-)'

Thanks,

RTC Vin #1815 Auto w/48k miles

RTCraver

[Andrew]

I'm running Hervey headers with a single Magnaflow Tru-X muffler mounted behind the engine in the stock muffler location. I had the pipes custom bent at a local exhaust shop. I've been happy with the look, sound and performance. Others have said that the Hervey headers with the dual Flowmasters are considerably louder, but I've never actually heard that particular setup, thus I can't speak to that system firsthand.

As noted in other posts, I'm also running the Peugeot 604 carb with the dual Solex carbs. I've been planning on getting 5052 dynoed, thus when I do I will post the results.