I have an APS TT with basic built motor (Arias,Eagle,ARP,HKS HG, valve springs). I track the car approximately once every week. I would like to know what you guys think is a good boost level for longevity. I would like to keep tracking the car for another 2 years without needing an engine rebuild. Any experience appreciated.

 

It realy depends on a lot of variables (driving style, track condition & lay out, car cooling mods & supporting mods, etc.) I would venture to guess that 10-14 psi would be ideal for your situation.

 

10psi most the time. Personally, I tend to be faster at 10psi vs. 15psi, at least on the tracks that I run. Even a well setup NA Z is awesome in the right hands, so a little boost goes a long way. I am still looking for those awesome hands. And probably THE most important thing, is keeping things cool, especially on those hot days.

 

Thanks guys. I have the usual cooling mods (PS and Oil Coolers). You're right Sharif, sometimes you can have too much power but since I'm running full slicks, traction has not been an issue.

Sharif, I PM'd you re your actuators. I think you sent me the green ones instead of yellow.

 

I agree with our friends Scott and Sharif, trend to the lower side on the boost continuum. Driver skill is going to be 80% of what happens with the results, and then 15% tires. I really think only about 5% is everything else, including the power. That is just my personal perspective and it may be lots of healthy disagreement will flow from the statement, but on a track circuit as we all know, it is driving corners, with a few bits connecting them called straights. Well driven momentum cars on twisty tracks just destroy big HP beasts with enough regularity that we know high hp is not THE answer. It is helpful, but not dispositive in many instances.
Some tracks reward monster power more than others. Out here, Willow Springs International Raceway, the big track, with only 9 turns, is perhaps the ultimate high hp course we have access to. The next would be California Speedway when the course is run with the big NASCAR Roval turn and the full length of the banked front straight. And of course 11 turn Laguna Seca with that run from turn 4 to 5 and then the long pull up hill through 6 and 7 to the very top and the corkscrew, and of course the front straight all the way down to Turn 2 and the Andretti hairpin.

But courses like Buttonwillow, Spring Mountain, Reno Fernley have limited opportunities for the monster power to be unleashed. Sears Point and Thunderhill have a balance for both, but I think the technical demands still favor a driver and handling over power.

So trending towards control of the boost with minimum lag and jolt is going to lead you to better lap times not to mention longevity.

As for two years on a set up, hard to say if you will make it or not. If you have four or five 25 minute sessions, and let us say you run on average four, and that you travel about 25 miles each session, that is 100 miles of race condition driving each weekend. You will have a few weekends off, and bad weather days and such, so figure max 40, or four thousand racing miles a year, and you are aiming to get 8,000 out of the motor. My impression is that is an awful lot of miles. If you baby her with religious maintenance and oil changes and all that good stuff, and use low boost, "maybe". But with that much running, your tire costs are going to be a lot more than your motor!

 

+1 same here

 

First time I heard it put that way, and it makes perfect sense.

 

For those that know Willow Springs big track, a 110 horsepower, 1,750 lb Spec Racer Ford can run a 1.32 lap after lap. From turn 5 all the way around to turn 3 all that's required is a very quick lift as you turn-in to 9 and a slightly longer lift as you turn-in for 1. Otherwise its foot to the floor.

And, despite words to the contrary, EVERY race track is a momentum race track if driven properly.

 

Yep, the big car just carries more of it!