ABOUT a month ago we showed you video of Raelene Drew's 1966 HR Holden Premier sedan running low nines at over 150mph with a column shift. It’s an amazing streeter that’s equally at home on the strip. Well, husband Mark has been doing some dyno development on the old girl so he can finally get that eight-second pass he’s been after, and we’ve been following along with the video cameras.
The first test session was a few weeks ago, and with 403 cubes of boosted LS under the bonnet, the old Holden made just over 600rwhp with 14psi boost. Following some tweaking by the guys at MPW, it made 697.1rwhp with 18psi, but at that level the intake temps were starting to climb.
You can check out the full feature on the HR in the September issue of Street Machine
“It just had a cheap intercooler in it,” Mark says, “and I think the rear housing is too small.”
This theory was proven at the track, where the HR ran 9.22@155mph. “The intake temp was getting too high and the ECU was pulling the timing back to 14 degrees during the run,” Mark reports. So they put in a thicker 100mm Plazmaman intercooler and added a new 80mm BorgWarner turbo with a larger rear housing. Then it was back to MPW for more dyno time.
On the first dyno run one of the intercooler pipes blew off, but they fixed that quickly and boosted it up again. With the boost set at just 16psi, the HR punched out 725rwhp, this time without the intake temps climbing into the stratosphere.
After playing with the boost pressure and timing, the 404 cube motor put 725hp through the rear hoops
So to summarise: Mark’s now making more power with less boost and lower intake temperatures. Let’s call that win, win, win! All he needs now is that eight-second timecard.