James Dempsey Jr's V6 Dodge IROC Daytona


Autocross anyone?


 Dynomax muffler, K&N stock replacement filter, 52 mm throttle body and timing bumped.  3287 lbs.  16.45 E.T.  83.95 MPH


 MP springs, Ram Air with K&N open filter.   15.66 E.T.  87.19 MPH


 180F thermostat, tune-up, 8 mm plug wires.  15.50 E.T.  87.11 MPH


 Phil Flow 5000 polished throttle body, underdrive pulley.  15.56 E.T.  87.81 MPH


 Removed 50 lb subwoofer, 4-wheel alignment.  15.44 E.T.  88.59 MPH


 No changes.  15.58 E.T.  88.39 MPH


 Cool weather, .40 gap plugs, practiced launching car.  15.36 E.T.  89.18 MPH

  James wrote me quite a letter about his Daytona, so in his own words without further ado;  

        Let me start off with background history.  My first taste of Dodge was an 87 Shadow ES.  When I got on the Internet in mid 95, the first site I found was Dempsey Bowling's.  Through his site I learned more about the 2.2 turbo.  Although I had thought that the SDAC was strictly for Shelbys I didn't join.  Big mistake.  Later on I had done some minor mods to my Shadow.

    When It came time to replace my 87 Shadow ES, I drew up a long list of turbocharged cars, import and domestic.  My friends thought I was stupid for looking for another "headache".  Since most of them were F-body fans, they wanted me to get a big V8.  Well I'm the type of person that likes to be different so I didn't listen.

    My IROC wasn't my first choice.  I had looked at other IROCs and R/Ts and wasn't happy with some of the options.  As a college student, I shied away from the R/T because of several engine problems and ABS brakes.  At the time I didn't know about the 2.5 TI.   Finally after two years and four ESs, IROCs and R/Ts I found my car in one of those weekly car ad newspapers.  A 92 IROC with a 5spd, fresh tires, 54000 miles, extend warranty and fresh paint.

    When I bought this car I thought it would be fully supported with aftermarket parts.  One call to Forward Motion killed that.  A few months later the car had a Dynomax cat-back kit and drop in air filter.  About this time I joined SDAC-NE since they didn't have any IROCs in the chapter.  Later that year I went to SDAC-7 and discovered Autocrossing.  In August 97 I hooked up with Gus and Wayne for my first experience in drag racing.  And finally at SDAC-8, I got my first taste at road racing.

    Now with the history lesson out of the way, I can go over what I have learned about my car.  To start, I'm not a fan of drag racing.  I prefer the challenge of autocrossing and the speed of roadracing.  Since drag racing is a good way to show gains in performance I have listed my results.

    The first mods that I did to the car were the Dynomax cat-back exhaust and K&N replacement air filter.  I found that this opened up the top end of the car.  Before the changes the engine hated to go above 5000 rpm.  This was done in Sept of 96.

    The next step was the increase in timing.  With Seth's helps at my first SDAC-NE meeting we changed the timing in the parking lot.  This did help a little, although it seems to help more at part throttle.  In the cold of Jan., late at night the timing was changed.

    The 52mm throttle body was next.  I learned about the throttle body over the Internet.  With Cliff Ramsdell's extensive garage of parts, I traded him an 87 MP computer for the throttle body.  I got the throttle body just before SDAC-7.  Don't forget to trim the throttle body gasket to the 52mm opening!  A year passed before I figured this out.

    Next was my first foray in drag racing.  The modifications at the time were drop in air filter, cat- back exhaust and 52mm throttle body with 46mm gasket.  With full stereo (6 speakers, sub, two amps) baseboard in trunk, spare tire and 3/4 tank of gas I ran my first best of 16.450 @ 83.95.  The car rang in at 3278 lbs.

    Next was the autocrossing suspension.  At SDAC-7 I learned quite a bit about the stock suspension.  While watching the R/Ts go down the quarter mile I noticed that the rear end would sag quite a lot.  Another lesson learned was how damaging Michigan roads can be.  With a blown strut and lessons learned with the Shadow, two months later my car was lowered and using MP struts and shocks.

    My second attempt at a cold air intake was next.  With Gus' help, we went to a tractor trailer parts store and I bought a three inch radiator hose to mount my huge K&N open air filter.  With some of Gus' tools I cut an edge off my battery tray so that the hose would clear.  This time the intake was a success.  Now the engine revved happily passed 5000 rpm.  My car was now faster then my friends MX-6 LS, Probe GT and 305 Chevy IROC.  For a year I had been basing my mods on whether or not I could beat the 305 IROC.

    My next drag racing adventure was an SDAC-NE event at Epping.  New modifications this time, were the autocrossing springs, no spare tire or board, 1/4 tank of gas and cold air intake.  This was the biggest gain that the car saw.  At 15.663 @ 87.19 with estimated weight of 3200 lbs.  I figured this weight because I weighed the spare tire at forty lbs., board was ten lbs., and sound proofing mat was fifteen. I also estimated the gas based on a gallon weighing six lbs.

    In April a tune up, 180-degree thermostat and 8mm MP wires were added.  Drag racing later in April netted a best of 15.504 @ 87.11 with car weight at 3146 lbs.  I was also trying and learning new launching techniques.  Later in the month my throttle body was upgraded to a Phil Flow 5000 unit thanks to Phil Whittemore.  Phil had disassembled the throttle body and smoothed out the passage and edged the butterfly.  I also learned that I needed to trim the original gasket.  The engine's throttle response was heightened with renewed vigor.

    In May the underdrive pulley was got its turn.  I found the engine revved with easy with several rev limitier bounces on a test run.  This was also the month of the SDAC-NE dyno day.  With everyone looking on with interest or doubt, my car made 153 hp at the wheels.  I may have been the lowest in horsepower, but a bet made early won me pizza.  I figured that the underdrive pulley won me that pizza by putting my over the 150 mark.

    June wasn't a good month for drag racing.  With the underdrive pulley and smoothed out throttle body I ran 15.562 @ 87.81 with the car at 3162 lbs.  Carrying more gas then needed, I wasn't able to post a lower time but the positive was the speed was up.  Thus showing some gain.

    August I replaced the cap and rotor because of problems and had the front end aligned for handling.  New camber setting for the front was -.3 degrees and -1 in the rear.  Since my tires from road racing showed extreme wear from roll I choose to get away from the stock settings.  Basically I was just learning how to drive.  This was the first time I removed the fifty-pound subwoofer in the trunk.  I posted a 15.442 at 88.59 as best that night.  With new alignment the car shows slight oversteer.  Even with the -1 camber in the rear I have still been able to throw/lose the rear several times.  Overall the car is more tossable with no front end push.

    In Sept. was the "Mopars at the Valley" at Lebanon New York.  This was my first bracket race and day race.  I broke out in my first round of brackets with a 15.587 @ 88.39 with the car at 3155 lbs.  With only two trial runs I posted a dial in of 15.6 since my runs were higher then this.  Oh well

    In the SDAC-NE's last drag racing event I ran a best of 15.3 @ 89.18.  The only change this time was the coil was moved to the front of the air plenum, replaced a bad MAP sensor, cleaned off the spark plugs and gapped them at the .040.  It was quite cold that night so I tend to think that the cold weather was in effect.

    So basically with a 52mm throttle body, cat-back exhaust, 180-degree thermostat, 8mm wires, MP autocrossing suspension, MP struts/shocks, cold air intake, coil moved, and underdrive pulley netted me a 15.3 @ 89 mph at the end of the racing season.  I was able to take over a full second off with a few changes and plenty of practice.

    In 99 I will be adding a high flow cat, an aftermarket timing computer from Holley or Superchips, adjustable fuel pressure regulator, konis, centerforce clutch and maybe ported intake and heads.

    I will also continue to explore whether to add a turbo or supercharger.  I hope to produce a kit that is affordable yet reliable.

James Dempsey Jr.
James's Homepage
Pictures courtesy of James Dempsy Jr.

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