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Topic: Dyno'd the 331 (Read 352 times) previous topic - next topic

Dyno'd the 331

So I built a 331 for my Coupe a few years back with the help of an engine builder over the phone back home being that I lived in Houston at the time.  I thought all went well and for the most part it did even though up to a few days ago I didn't think this way.  Turns out there were a couple of errors on my part but mostly small crap that could have been fixed with a small tear down with the engine in the car.  The one thing I could not fix was the rocker arm geometry issue on the Edelbrock Performer RPM heads.  The heli-coiled holes for the rocker studs had to be welded up and relocated due to known issues with this on the Performer and Performer RPM heads that Edelbrock will not correct.  They are okay with a stock or very mild lift cam but not a performance cam.  My engine builder has come across this a few times so he had the heads welded up and then put them on a mill to correct the issue.  Then all new bearings were installed, new piston rings (might as well being we had it apart), degreed the cam according to Ed Curtis' instructions and not straight up like this dummy did, and fixed some other minor things that 30+ years of engine building gets you.

I put the motor back in the car a few weeks back along with a new RAM clutch so I have been keeping the rpm's below 4,000 while getting a couple hundred miles on the new clutch before it went to the dyno.  I also picked up a new set of 275/40/17 Nitto 555R's for the rear as the other tires (Kumho) were garbage from day one.  Not really knowing how bad the tune was out I was still unimpressed with the 331 and wondering if I should have gone for the 347.  I just got a smoking deal on the 331 kit ($450 SCAT kit never installed) so that is why I went with a 331.  Supposed to be a better rod angle as well but most newer 347 kits have corrected that by moving the wrist pin in the piston.

Anyhow, I left after work this past Thursday afternoon and drove down to my home town to get my buddy's car trailer (3 hours) and then over to my dad's shop to load my car (2 hours) and then cooled off, grabbed a bite to eat, a couple of bottles of water and then drove to my hotel in McKinney, TX and arrived there at 12:15am on Friday.  Got up at 7:30 and was down at True Streets Performance shop with the car unloaded and parked in front of the dyno bay at 8:55am for a 9:00am appointment.  Met the tuner (Archie) and got on the dyno at 10:30am.  He had a Mopar up on the dyno and needed to finish it up before he started on mine which was okay with me as I was busy looking at all the other cars they had there.  Had to be at least 30 cars with Fords being the majority but they did have a Grand National that was putting down around 650 rwhp, couple of Mopars, and a couple Bowties all making more power than me but I think they all had some kind of forced induction.   Archie spent until 2:00p tuning on the Coupe and I got back to my dad's shop in Oklahoma around 5:30pm...a very long 24 hours.

Archie was awesome to watch work and just a super nice guy.  So I was outside when he made the first pull on the existing tune and I heard the sound of a motor lean in the upper rpm's.  My guess was around 4,000 rpm and he confirmed it was 4,500 and just got worse as it went up to 6,000.  By the sixth pull it sounded really good and he came inside the show room.  He asked if I had an MSD in the car, where the hell it was mounted (he looked in all the usual spots and could not find it), and if I did have one what chip I had in it.  I told him it was tucked away behind the front bumper on the driver side and I thought it had a 6,200 rpm chip in it.  He came back inside with a smile on his face and tossed me a 6,000 rpm chip (woops) and said he was going to let the EEC do the rev limiting as the MSD's limiter was not as accurate and then he went back to tuning.   He made two more pulls and came back inside and said he deleted the O2's from the EEC so I can now unplug them and plug the holes in the X-pipe.  Said the signal on them is usually crap and he can tune without them and the signal on mine was crap.  He wanted to let the motor cool off and make a couple more pulls to mess with the idle and tune on the low rpm range.  So with all of that the new shift point is 6,500 rpm and it ended up with 364 rwhp and 386 ft-lbs of torque out of the 331.  One other thing, I have 42 lb/hr injectors and I am 60 to 70 hp from running out of injector at 52 psi of pressure.  Those that think 30's or 36's will be okay on a naturally aspirated 331 or 347 need to rethink this.  Just passing on what works in my car so take it with a grain of salt.

So I worked on my F100 on Saturday and then went to the races that night so I did not driver the Coupe that day.  Woke up on Sunday morning and it was 72 degrees so I took the car for a spin around town and then out of town on a long stretch of no car in sight four lane...I can tell you triple digits are almost had at the top of third but it smashes them in fourth.

83 351W TKO'd T-Bird on the bottle


93 331 Mustang coupe that beat your mom's LTD

Re: Dyno'd the 331

Reply #1
Nice!  That sounds like a very long day getting there and back.

What are your thoughts now comparing this motor on how it runs compared to your 351W?  I am not sure what you had done to the 351.
1988 Thunderbird TC, 5spd
Stinger single exhaust, Cone Filter, Adjustable Cam Pulley, Ranger roller cam conversion,
'93 Mustang Cobra replica wheels on 235/50R17

'16 F150 XLT 5.0
'17 Husqvarna TX300

Re: Dyno'd the 331

Reply #2
Good right up!   
84 COUGAR/90 HO, 1.7RRs, performer RPM,700DP, equal length shorties, stainless EXH ,T-5,Hurst pro-billet, KC clutch, 8.8/ 4.10s, line-lok, bla ,bla, bla.
71 COMET/289,351w heads, 12.5 TRWs, 750DP, Liberty TL, 9"/6.00s, 11.9x @112 , bla,bla,bla.

Never shoot your mouth off, unless your brain is loaded! ....I may get older, but I'll never grow up!....If you're not laughing, you're not living!  :laughing:

Re: Dyno'd the 331

Reply #3
So comparing the 331 to the 351 is like a flash bang to a grenade if that makes sense.  The 351 makes about 450 at the rear wheels without the nitrous and the Bird weighs a few hundred pounds more.

So the build on the 351 is like this from the top down:
Carburetor - Holley 750 double pumper modded by the Carb Shop in California to an 830 with their road race package
Intake - Edelbrock Victor Jr that is gasket matched to the heads and just cleaned up of casting flash down the runners
Heads - AFR 185's with mild port work, Manley SS valves, Isky 8005 springs, titanium retainers and keepers, ARP rocker studs, Comp Cams Pro Magnum roller rockers & stud girdles, and ARP studs to fasten them to the block
Block - Stock '94 Ford roller block that has been magnafluxed for cracks, bored .030" with torque plates, line honed, Probe Street Fighter main girdle, and some work done on the oil passages
Rotating Assembly - Ford SVO billet 351 crank (no stroke), Probe I-beam rods, Probe SRS pistons, Probe ring package, King bearings, Ford SV billet flywheel, Ford SVO balancer, and RAM clutch assembly all with ARP fasteners
Cam - Comp Cams 35-450-8 (cam specs here http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=1047&sb=2) with a billet adjustable timing gear set

If you want to dive further into the car then I did have a couple threads on the motor, fuel system and exhaust:

Going from the 302 to the 351 - https://www.foxtbirdcougarforums.com/index.php?topic=33877.0
Custom Exhaust - https://www.foxtbirdcougarforums.com/index.php?topic=31210.0

Anyhow, they are two different cars and two very different motors.  I will say one thing though, if you put 302 parts on a 351 you will make 302 power.  What ever you build just understand that you need to set a goal and know what you are building the motor for like street, drag, road racing, etc.  The cam is the brains of the whole operation so know what kind of power you want to build and what rpm range and if you are going to be injected or carb'd  from there you can start mapping the rest of the motor out.

83 351W TKO'd T-Bird on the bottle


93 331 Mustang coupe that beat your mom's LTD

Re: Dyno'd the 331

Reply #4
He made two more pulls and came back inside and said he deleted the O2's from the EEC so I can now unplug them and plug the holes in the X-pipe.  Said the signal on them is usually crap and he can tune without them and the signal on mine was crap.
Sounds sort of ghetto to me.  :dunno:



Re: Dyno'd the 331

Reply #5
Lots of tuners delete the O2 input...

Why is this a surprise?

Nobody even knows their O2's are out of range unless they test 'em....or a new(er) vehicle throws a light or code...
'84 and '87 Mustangs
'98 Explorer 5.0
'06 Lexus
'06 Explorer EB 4.6

Re: Dyno'd the 331

Reply #6
Lots of tuners delete the O2 input...
Lots of tuners do lots of stupid things (I'm not implying Aerocoupe 's tuner is stupid).

Deleting the rear O2s is common (in applications that have them), as they don't affect performance/drivability - they just let the user know when the cats dead.
Quote
Nobody even knows their O2's are out of range unless they test 'em....or a new(er) vehicle throws a light or code...
The front O2s in closed loop (>99% of time spend driving) help fuel efficiency, drivability, and emmissions.
As long as the trim is +/- 25% of  nominal, the O2s can get the AFR back to stoichiometric for good fuel economy without bucking.

Going Open Loop 100% of the time is generally a strategy used when properly tuning the vehicle is too hard or time consuming. Instead of really nailing down the MAF table or SD tables, you can specify OL 100% of the time, richen the mixure a bit over stoichiometric and just take the mpg and emissions hit.

Aerocoupe might have some insight as to why his tuner went full OL tune, but I've never seen a good reason (for me) to go that route.

Re: Dyno'd the 331

Reply #7
Thank you for explaining your setup.  I was under the impression you had put the 331 back in the TBird, but I see I was wrong.
I have a 351W that I have been playing with the idea of doing the swap.  Your setup looks to me to be a full throttle blast!  Fun!  For now I think I will keep my setup a bit mellower for a broad torque curve.

I've been reading your car setup (TBird) and keep going back for more.  I am really enjoying your F100 thread.




So comparing the 331 to the 351 is like a flash bang to a grenade if that makes sense.  The 351 makes about 450 at the rear wheels without the nitrous and the Bird weighs a few hundred pounds more.

So the build on the 351 is like this from the top down:
Carburetor - Holley 750 double pumper modded by the Carb Shop in California to an 830 with their road race package
Intake - Edelbrock Victor Jr that is gasket matched to the heads and just cleaned up of casting flash down the runners
Heads - AFR 185's with mild port work, Manley SS valves, Isky 8005 springs, titanium retainers and keepers, ARP rocker studs, Comp Cams Pro Magnum roller rockers & stud girdles, and ARP studs to fasten them to the block
Block - Stock '94 Ford roller block that has been magnafluxed for cracks, bored .030" with torque plates, line honed, Probe Street Fighter main girdle, and some work done on the oil passages
Rotating Assembly - Ford SVO billet 351 crank (no stroke), Probe I-beam rods, Probe SRS pistons, Probe ring package, King bearings, Ford SV billet flywheel, Ford SVO balancer, and RAM clutch assembly all with ARP fasteners
Cam - Comp Cams 35-450-8 (cam specs here http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=1047&sb=2) with a billet adjustable timing gear set

If you want to dive further into the car then I did have a couple threads on the motor, fuel system and exhaust:

Going from the 302 to the 351 - https://www.foxtbirdcougarforums.com/index.php?topic=33877.0
Custom Exhaust - https://www.foxtbirdcougarforums.com/index.php?topic=31210.0

Anyhow, they are two different cars and two very different motors.  I will say one thing though, if you put 302 parts on a 351 you will make 302 power.  What ever you build just understand that you need to set a goal and know what you are building the motor for like street, drag, road racing, etc.  The cam is the brains of the whole operation so know what kind of power you want to build and what rpm range and if you are going to be injected or carb'd  from there you can start mapping the rest of the motor out.
put the 331 back in the T-Bird
So comparing the 331 to the 351 is like a flash bang to a grenade if that makes sense.  The 351 makes about 450 at the rear wheels without the nitrous and the Bird weighs a few hundred pounds more.

So the build on the 351 is like this from the top down:
Carburetor - Holley 750 double pumper modded by the Carb Shop in California to an 830 with their road race package
Intake - Edelbrock Victor Jr that is gasket matched to the heads and just cleaned up of casting flash down the runners
Heads - AFR 185's with mild port work, Manley SS valves, Isky 8005 springs, titanium retainers and keepers, ARP rocker studs, Comp Cams Pro Magnum roller rockers & stud girdles, and ARP studs to fasten them to the block
Block - Stock '94 Ford roller block that has been magnafluxed for cracks, bored .030" with torque plates, line honed, Probe Street Fighter main girdle, and some work done on the oil passages
Rotating Assembly - Ford SVO billet 351 crank (no stroke), Probe I-beam rods, Probe SRS pistons, Probe ring package, King bearings, Ford SV billet flywheel, Ford SVO balancer, and RAM clutch assembly all with ARP fasteners
Cam - Comp Cams 35-450-8 (cam specs here http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=1047&sb=2) with a billet adjustable timing gear set

If you want to dive further into the car then I did have a couple threads on the motor, fuel system and exhaust:

Going from the 302 to the 351 - https://www.foxtbirdcougarforums.com/index.php?topic=33877.0
Custom Exhaust - https://www.foxtbirdcougarforums.com/index.php?topic=31210.0

Anyhow, they are two different cars and two very different motors.  I will say one thing though, if you put 302 parts on a 351 you will make 302 power.  What ever you build just understand that you need to set a goal and know what you are building the motor for like street, drag, road racing, etc.  The cam is the brains of the whole operation so know what kind of power you want to build and what rpm range and if you are going to be injected or carb'd  from there you can start mapping the rest of the motor out.
1988 Thunderbird TC, 5spd
Stinger single exhaust, Cone Filter, Adjustable Cam Pulley, Ranger roller cam conversion,
'93 Mustang Cobra replica wheels on 235/50R17

'16 F150 XLT 5.0
'17 Husqvarna TX300

Re: Dyno'd the 331

Reply #8
He made two more pulls and came back inside and said he deleted the O2's from the EEC so I can now unplug them and plug the holes in the X-pipe.  Said the signal on them is usually crap and he can tune without them and the signal on mine was crap.
Sounds sort of ghetto to me.  :dunno:




Yeah I don't get why the O2s were deleted either. I'd like to hear why though.
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

Re: Dyno'd the 331

Reply #9
The reason given to me was the signal from the O2's was garbage and he sees this a lot on the older systems like the EEC-IV's which only have one O2 per side not four like the newer Mustangs.  I have had four different tuners tune this car over the years and I can tell you that this is absolutely the best tune it has ever had.  Idle is fantastic (no surging what so ever), part throttle is smooth as silk, and the power it makes is very linear.  The area under the torque curve is huge.  It comes up on torque quick and builds power all the way up to 6,500.

I am not a tuner but I do have a basic understanding of how the EEC-IV functions.  I am not going to internet second guess a guy that came as highly recommended as Archie has and I talked to some of the guys that own the cars he has tuned with nothing but high regards for his ability.   If you are curious as to his reasoning give him a call at True Street Motorsports at (972) 542-9886.

83 351W TKO'd T-Bird on the bottle


93 331 Mustang coupe that beat your mom's LTD

Re: Dyno'd the 331

Reply #10
I worked quite a few years at a shop here in Maryland that has both engine and chassis dyno. Both were Superflow and considered top tier when purchased in the late '90's. My Cougar at the time had a 375 CI windsor that had made a little over 500 HP on another shops' engine dyno. Installed it in my car and went to the track. Car usually would run 11.50's with the best being 11.30's. When we got the chassis dyno set up, I spent a weekend tuning and could only pull 350 and change at the rear wheel. I finally decided I was more interested in the A/F and 1/4 mile E.T. than trying to figure out which dyno numbers to believe. I used to joke that I must have been the baddest guy with 350 RWHP. At 3300Lbs, it ran ok and after 2 years I built the 408 currently in the car. Never had that engine on engine or chassis dyno, as I decided I didn't want to get caught up in the numbers. New combo ran 10.80's between 123-125 MPH. We had dynoed two other 408 Engines that we built at the same time, with diferent carbs and different headers-both cars produced between 380-400 RWHP. One had a Tremec and the other a C4 with a Gear Vendors. How well the car runs and 1/4 mile performance for those that like to go to the strip are the best numbers. Dynos vary alot from shop to shop.
1988 LX, 306 with GT40P heads, Downs Upper Intake on Truck Lower, Powerdyne Supercharger and T5 swap.  Scavenger Hunt Build at it's best.


Re: Dyno'd the 331

Reply #12
I live in Westminster. I worked for Maryland Performance Center for 22 years (they are currently in Frederick Maryland). I now work with a bunch of former co workers at Bruno's Classic Muscle in  Rockville, Maryland. Sorry in advance for de railing someone else's thread.
1988 LX, 306 with GT40P heads, Downs Upper Intake on Truck Lower, Powerdyne Supercharger and T5 swap.  Scavenger Hunt Build at it's best.