[DeTomaso] 4.6 update

[John Taphorn]

Dave

Congrats, what mods did you make to the mufflers that you believe may have 
been responsible for the improved high RPM performance?

JT
----- Original Message ----- 
From: "Dave Doddek" <pantera at pobox.com>
To: <detomaso at realbig.com>
Sent: Wednesday, November 08, 2006 11:13 PM
Subject: [DeTomaso] 4.6 update


> 4.6 Update
>
> I finally got the 4.6 project done.  It is tuned and headed back home with
> its owner.  Tuning went very well.  The SCT software to program the 4.6 
> was
> easy to use and even allowed me to datalog the wide band O2 sensor along
> with other data.  We took it to the dyno shop this weekend for a couple of
> pulls.  We wanted to check for any odd spikes or dips in the hp curve and
> test our muffler modifications.
>
> The horsepower results were pretty good.  We started with a 285hp engine
> stock.  No internal modifications.  We added long tube headers for the
> Pantera, a home made blower manifold and an Eaton supercharger with a 5.5
> lb pulley.  It made 284 hp at the wheels with 321 lbs torque at 3400 rpm.
> Really good torque and at a nice low value.  Torque was above 275 lbs from
> 2000 to 5000 rpm.  The curves were very smooth with no areas to worry
> about.  But what was most interesting was the horsepower curve.  Instead 
> of
> running up to peak and then dropping off like most engines, it went to 284
> hp at 5000 rpm and just stayed flat till 7000 rpm.  I expect we could of
> easily turned 7500 or 8000 rpm with the stock cams.  It would be neat to
> see what would happen with a better bottom end and more boost.  I bet this
> engine could easily make 400 at the wheels and turn 8000 rpm.  The engine
> sounded great with no pops or cutouts.
>
> The computer was adjusted conservative with only 14 degrees of timing and 
> a
> 12.5:1 fuel ratio.  Next summer we will see if we can bump it up and get
> another 40 hp.  That will be over 300hp at the wheels and 400hp at the
> crank assuming 25% loss.  Pretty good for a little engine.  Based on what 
> I
> have learned about these engines, They can make big power with a new
> calibration and a good intake.  Factory intakes seem to cost more power
> than exhaust especially when you can add long tube headers to a Mustang 
> and
> gain only 12 hp.
>
> Since the HP curve did not drop off, we believe we fixed the mysterious
> power loss with stock GTS mufflers.  It would be interesting to try this
> same muffler modification on a Cleveland powered car and compare before 
> and
> after dyno results.  We also experimented with a plug in one of the 
> exhaust
> tips.  We inserted a tube about 8 inches long with a 1/2 inch washer 
> welded
> to the end into one tip on each side.  This makes the car just a little
> quieter but greatly reduces the rumble at idle and certain rpms.  The dyno
> showed we lost only 6 hp peak with the loss starting at 3000 rpm.
>
> As a final note on comparison, the stock Cleveland made 194 hp at 5200 and
> 212 lbs torque at 4500.  This 4.6 actually makes more torque at lower rpm.
> The Cleveland got 19mpg best at 60mph.  The new 4.6 today got 24.5mpg at
> 70mph.
>
> But best of all, ITS NOT IN MY GARAGE ANY MORE!!!!!!!
>
> Here is the dyno chart and a video of the pull.
>
> http://members.aol.com/ddoddek/alandyno.jpg
> http://members.aol.com/ddoddek/alandyno.mpg
>
>
>
> Dave "wow, what a project" D
>
> _______________________________________________
>
> Detomaso Forum Managed by POCA
>
> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
>
> DeTomaso mailing list
> DeTomaso at realbig.com
> http://ftl.realbig.com/mailman/listinfo/detomaso