Reliability w/Mods

[911/Q45]

I just read the speedy car shootout in Motor Trend and was struck by the reliability of the factory hot rods. They ran the whey out of them without a malfunction and then drove them back to LA from Kingman, AZ. When they have their tuner car shootout about half the cars blow up before they complete the tests. There must be a lesson there for us go faster guys!

[greg_atlanta]

But those were new cars, right?

I think some mods are questionable for long term reliability, like 100K+ miles.

[Q45Viper]

As a Viper owner I follow some of this stuff closely. including the article mentioned. You guys are blessed to be hanging out on a board with some extremely knowledgeable techies who slow us down when we get too wild with mods. I just went through a long discussion with Q45 tech and others regarding JWT ecu/tcu upgrades. I feel EXTREMELY confident in the advice given by Dennis and Fred and others regarding the MILD uprades we do and the restraints that these guys go to great lengths to advise us of. The tuner cars you speak of are attempting to double rwhp, some are really grenade motors meant to impress the magazines and draw the suckers in. Hennessy is a prime example of a Viper tuner doing that. amazing stories of 30k being spent on a car and it dynos 20hp over stock, amazing stories of guys sending their cars there and a check fo 100k and nothing happens for a year. That is a different world than what we are doing, and we are not attempting to double horsepower with our Q's. For what it's worth I would not go the route some of my Viper brothers have taken either, I like that car too much to blow it up also. All things with moderation. I mean really, last pull was 435 rwhp with smooth tubes, k&n and cat back, I don't neeed any more than that! and I think that the Q can well withstand the mild ecu/tcu mods presented by the experts on this board. More important are the maintenance issues addressed here, listen to the experts here and you will get a lot more performance and LONGEVITY out of a Q. Leave the superchargers to the guys who still have warranty left to play around with.

[QShip]

You said that very well.

Do you think a Viper engine will fit into the Q? Just kidd'n:)

[Q45tech]

Notice that tuners like Stillen or JWT have limits..........almost any engine has a reserve of 25-30% [primarily in rods] over building is a way to extend life or assure that 99.9% don't fail during the warranty period.

The nicest thing about radial superchargers is than the psi increase as the square of speed [8 psi @ 6500 vs 2 psi @ 3250] and the drap HP required also increases at the same rate 20 vs 5. The temperature rise is a function of psi [roughly 10F per psi plus say 20F for exposed area to under hood].

All these things are somewhat self protective as long as you run excessly rich AF and have a good spark.

No boost, little drag and may 20F hotter air at cruise, by 4,000 still little [maybe 6-10% NET].

How many times per day per week do non supercharged Q hit 6,000 rpms+. After the fun wears off I doubt supercharged Q will be driven much more aggressive much more often........the ideal low stress solution.

The whole trick is to reverse engineer the system so that say you never exceed 340 lb/ft under any boost condition. An amount of temperature corrected boost that just matches the fall in volumetric efficiency of the normal motor without a supercharger ............this would be just at or slightly under 400HP at 6500 rpm 400 x 0.8= 320 lb/ft SAFE.

What one must do is limit the max rpm to compensate for the added pressure......7300 x 0.9= 6570 rpm vs 6900 normal redline to ensure rod/ring longevity.

What many forget is the supercharger is consumming 20-25-30 HP just to turn itself and make the boost and heat the charge.

So getting 425 GROSS [400 NET] [315 RWHP] vs 300 NET stock [235 RWHP] is stilll pretty impressive.