I am new to the LS world and I have acquired a RX7 with a ls6 in it. Here are the specs for the build that he gave me.

LS6 block NEW Stroked to 383ci
Wiseco Piston set
Eagle H-beam rods w/ ARP rod bolts
Callies Compstar Crankshaft
ARP main stud kit

Trick Flow GEN X heads
Trick Flow Cam .585in/.585in lift
Trick Flow Roller Rockers

( I am pretty sure this whole set is this http://www.summitracing.com/parts/tf...make/chevrolet )

Fast 92mm intake manifold
92mm Throtle body
42lb injectors
Twin Walbro fuel pumps
NOS 125 wet shot (dyno tune auto bottle heater NIB)
Hinson supercars headers W 3.5in exhaust
LS7 clutch
LS7 aluminum flywheel
T56 6 Speed Trans
Hinson super cars aluminum drive shaft
Hinson super cars LS V8 mounting kit
Hinson super cars aluminum radiatior

After I drove it for awhile my butt dyno had told me it was making at least 500hp. I was not sure if he had ever had it properly tuned (even though he said the engine was built at texas speed). So i went and got it tuned. The kicker is that it was only showing 425rwhp and 420 torque. Are these figures correct? I thought that after the head and cam swap that these engines really opened up? I read the application for the Summit racing part (see red above) and it says its for LS1, but the liters are the same. Will that make a difference? FWIW I didn't buy these upgrades, but I am a little ashamed of the meager output they gave me. I will probably be pulling the NO2 out and going Pro-Charger to raise them up

 

Mustang dyno or Dynojet dyno? Actually it really doesn't matter..i've personally seen dynos vary quite a bit. Run it at the strip...the trap speed will be the true indicator

 

Dont get your head wrapped around numbers. Thats all they are, numbers. Take it to the track and see how it runs then make adjustments as need be. No need to starting pulling the nitrous and going with a procharger just to "raise them up"

 

My head isn't tooo wrapped around it. Just with the head swap and cam swap I just assumed that they would be higher. I will take it to the track next year when I get back to her, but as I sit here away...I just want 500 rwhp!!!!

 

That doesn't sound correct, even with a stingy dyno those number's seem low. Run it through the quarter and see what you trap.

 

the number Summit claims is @ the Flywheel not RWHP. Pull that cam and go a little bigger

 

1. Those summit numbers are rated at the flywheel, not at the wheels.
2. That is a smaller/midsized cam, you wont get close to 500RWHP with that.

Just because its a "heads/cam" engine doesn't mean it will make big power, not all heads and cams are the same, and intake/exhaust can make a hell of a difference as well.
Do your research and don't just randomly buy things, you want 500rwhp you should have searched.
https://ls1tech.com/forums/generatio...heads-cam.html

 

I didn't buy anything, except the car. This was the build he had done at texas motors. I was just surprised that he put all this money into it (heads,cams,intake mani, big exhaust) and thats the small amount of hp he got. I just today found that summit reference, I'm not saying for sure thats what he got...but I would assume since it matched some of the specs. I have been reading that "recipe" to 500 rwhp today. As you can see from my post count and from what I first said, I'm new to this and I'm across the world from my car now so I have big dreams.

 

I think you might be surprised how fast the car really is despite that low dyno number

 

Ahh, I see. So is this the exact build specs he gave you?
The more accurate information you give us on here the easier we can help you to see if something is actually wrong, or if everything is fine and the original owner just wanted to build a fun street car.
First, you'll see on here that people are not all hung up with peak hp numbers like some guys are. We generally care about how the car actually performs. Most here will build the car to run a certain time, not a certain peak hp.
Second, maybe the previous owner just threw some mix and match parts on and isn't taking full advantage of what the engine is capable of. Or he just wanted a mean street machine (like you said the car feels like a beast, but the numbers are not what you expected). Going with a big radical cam can hurt driveabilty on the street, so maybe thats why he opted for a smaller more friendly cam.
Call the previous owner or the shop (if he used a shop) and find out more about the car, then go from there.

EDIT: also thinking since its an RX7 maybe the previous owner was roadracing/autoxing it and not really drag racing? You don't really need (or want) big power for that, especially since the car is what, 2800lbs with the engine swap and everything?

 

Understatement! haha I drove it for a month last year when I was back in the states, it was amazing! I went from a 1994 nissan micra (my daily driver with less than a liter) to this thing!

 

I think this was what it was. The vibe he threw off was that he was rich and just bought things. His garage was amazing car wise, not tool wise. Not sure he was racing it

I'm excited to actually use it to its potential, less than a year now and I'll be back.

 

Lol yeah just a SLIGHT difference! That stroker will make some nice torque as well

 

Agreed with this guy^

 

1) are you sure that the engine has all those parts mentioned?

2) did you get it checked out to see that it's running properly?

Without knowing the cam specs it's tough to really say what numbers you should have. Although a 383 with even a small cam should easily make those numbers, especially with those heads.

Now the biggest question is...who tuned it and how good are they at tuning LSx powered cars? This could all be in the tune, and you seem to have overwritten any tune done by the previous owner with your own shop's tune.