Geoff

iTrader: (3)

I would like to give out a few details about our entry in Factory Stock as well as thank a few people for their help.

Our motor is using Stage 2 GTP 5.3L cylinder heads. The flow numbers are nothing out of the ordinary as far as what these heads typically flow. We have sold sets to customers that have flowed slightly better! Our motor is also using a hydraulic roller camshaft and valvetrain. The cam lobes are something new we are trying with the express purpose of being very stable at high RPM's. In testing this motor has pulled cleanly out to 8200 RPM using Comp 26921 valvesprings. The cam in this motor is also small...240@.050" on the intake. The cam was a conservative first development step in this motor program. I'm not giving up any more of the details of the valvetrain, due to the competitive nature of this class. The parts in this motor aren't presently for sale, when and if they are, I will gladly give out any details on them. We intend once some more development is done to be able to offer this engine as a complete package to race in Factory Stock.

The compression ratio of the engine is 13 to 1. We are also using a sheetmetal intake designed with high RPM power in mind. I am of the mind-set that horsepower wins all-out drag races NOT low-end torque.

With the weight out of the car Angie reported to me that it went 10.265 @ 132.3 MPH. The torque converter and gearing presently are optimized for the old motor combination which was more of a torque motor and not meant to rev nearly as high as what we are doing now. I feel that once we get our converter and gear sorted out much quicker times will result. I will also go out on a limb and state that by this time next year competitive entry's in the Factory Stock class will probably need to be running 9.70's or better with the present rules structure in place.

I would also like to thank EVERYONE who works for Angie and me at Thunder Racing for all of the help in getting the car ready on schedule at the last minute. We are finally getting in the groove in getting ready for the races in spite of the usual last minute hiccups when you make extreme changes to a combination. Thanks goes out to Paul for driving the car also.

There have also been a few key vendors that have been a tremendous help with this deal. I can't mention them all, but they know who they are...thanks a lot.

RUQWIKR

iTrader: (11)

Saw your great last pass and was glad I brought the LS6 Baby Blazer and did not work too hard to get my car ready! You are right, it will take a lot of motor like you and FEAR THE LS1, etc. to be competitive going forward.

I think I'd been, at best, 10.70's right now with the extra 200#'s in the car I needed to add. You two, at the very least, would have gracious put me on the trailer real quickly.

Nevertheless, I am shooting for some 10.30's this fall with the stock bottom end, stock 4L60E (except converter), and my "small cam", albeit, at around 3000#'s raceweight vs. 3350# with some additional weight reduction.

The only bad thing to say about the event had to do with the track operation...how many times and classes did they screw something up...lots!!!

Safe travels, happy Father's Day, and good luck to all with your projects. Take care. Dave

Ben R

If you believe that HP is more important than TQ in winning a race, especially in a light car, what made you go with 5.3 Heads? Wouldn't an LS6/LQ9 head provide more peak HP?

I guess my logic is that if you're already building a high-compression motor, you don't have to worry about gaining compression with the 5.3L Head and can be focused on good flow numbers up top, especially if you plan on revving it to 8,200 RPM.

Geoff

iTrader: (3)

In my opinion I would always prefer to have a smaller port cross-sectional area for a given CFM. In fact I might be willing to give up a few CFM (this is the tricky part...you definitely need a certain CFM for a given engine size and speed) if it means keeping the cross-sectional area smaller. In other words if I have a 5.3L port with a 2.00" Intake valve and a 215 CC runner that flows 310 CFM or a LS6 port with a 2.08" Intake valve and a 235 CC runner that flows 315 CFM guess which one will make more power? I think the smaller port will give better cylinder filling (even at 8200 RPM) with the small disparity in flow for large disparity in the size of the ports. Does this make sense what I am saying?

If I have 2 ports that flow the same I am always going to go for the smaller of the 2. For a given CFM requirement for an engine at a given RPM, cam timing, intake manifold and exhaust header tuning will either allow you to get the RPM's you are looking for or kill you if you are off. Air speed can only help in any RPM range.

Lastly I don't like to run big dome on a piston if I can get away without it. The 5.3L heads are easier to build compression with.

Ben R

I understand that first paragraph, and I see the logic behind it. What about welding up the heads? Would that be an option for the LS6 head?

Geoff

iTrader: (3)

Welding is definitely an option. However the heat treat can become a real big deal. IMHO the heads probably need to be reheattreated (is that a word?) if welded up in the combustion chambers. For drag racing you might get away without a heat treat for a while but it would probably be suspect without some kind of hardness testing. I would feel more safe welding up ports rather than combustion chambers. If the chambers are soft the seats will wind up sinking into the heads or falling out. If the ports are slightly soft you are a lot less likely to have catatrophic damage. All IMHO of course.

ONEBADWS6

iTrader: (22)

Is this car running a FAST system? How did you get it to spin to 8200rpm?

Coach 02 A3 Z/28

iTrader: (10)

Thunder Racing is on the move. Congrats to everyone at the shop.

Great running Hot Rod ya'll have.

Coach

Angie

iTrader: (4)

I don't know all of the details, but it's still running on the stock computer.

Angie

Hawkn01

iTrader: (1)

Congrats on the times ! 8200 rpm has got to sound sweet going down the track !..........I'm drooling just thinking about it

Reckless

iTrader: (9)

You guys did well as always Paul. If you need a driver for the Thunder race, I will volunteer. I know you won't race because of the ethics involved. So I will make a sacrifice and drive the car at the race and even pay the entry fee Good seeing y'all again

Louis

iTrader: (7)

Geoff,

Since the car still has the factory computer- with MAF limitations at ~7200, is it in speed density Or once the car looses the MAF, do you just go to the PE v RPM table?

This stock CID class really woke up all of a sudden, its definately a a neat class

66ImpalaLT1

Aside from MAF, whats the rpm limit of the stock pcm?

SilverSurfer

So what's the big secret with the valve train? Using smaller rocker arms, 1.5s or 1.6s vs the stock ones? Anderson, Mustang tuner/racer, and many others have been doing this for a long time and has been able to eclipse 7200 rpm with the factory stock hyd roller lifter in 5.0s for years. And the stock 5.0 lifter is not as good as the LS1 lifter. When using stock sized rockers on a 5.0 the stock lifters begin to colapse at 6200 rpm with elevated spring pressures. A smaller rocker higher lift cam is much easier on the valve train and will allow it to rev much smoother and higher.

Camaroholic

iTrader: (1)

I talked to Geoff today about their car. Didn't get a whole lot, except that this is an all out motor.

He told me that to rev that high with the hydraulic rollers, the valvetrain is *very* light. *Very*. That's all he said. I would "assume" that it may have some more exotic components in it (titanium valves?). He didn't say that, but I know Thunder has used them in other motors in the past.

He is running a MAF right now, but we discussed VE (MAF-less) tuning as well. He's not there yet, but he's considering it.

It also has a Hogan sheet metal intake, ~13:1 compression, etc. Sounds like fun.