The crossflow flowmaster is the worst design ever! but they did not build it for all out performance,it was more for sound!!
I have 1 chamber flows out back and they definately work.....Another guy on Ls1 tech dyno'd his car with the same 1 ch.flow and he put down 386 whp and pulled the mufflers off and only gained 2 hp!

 

I have almost the same setup but I have hooker long tubes through magnaflow, and I also have 1.6 r.r. on . I made 397 rwhp and 365 trq througha 9". I would look at your lash, maybe a little tight. I run mine @1/8 turn.
tim

 

damn when I had my z28 I dynoed 355rwhp with just a cai a tune and a cc306 stock heads and manifolds.... the numbers dont look right for all the mods you have

 

I say the numbers are just fine.

Dyno numbers are for people who dont (or cant) put it on the track.

There are probably 50 reasons why any given car did or did not make the numbers the owner wanted. Put it on the track and see what it does.

I think you numbers are decent. You put down 340 HP. If it runs 11.50's then who cares what the numbers are?

Your converter was locked and therefore you did not have any "extra" losses because of converter flash or slip. Its a nice graph, fairly smooth and broad. It will be a beast on the street thats for sure!

FWIW, I have a ton more motor than you and I only put down 400 RWHP on a dyno.(wanna hear my list of reasons why? ) Put my car on the track next to a guy who put down 450 with dyno glory up his butt and I'll probably win Dont worry about the numbers, they dont mean much. Just a good referance point to work from. Good job and get that baby to the track and see how hard you have to work to keep it going straight

 

Dont get me wrong about my post about the dreaded 847, main problem i normally hear is drivability and the non existant power at low to mid rpm range, i think some people throw in the big stick just to say they have it.

Im betting he will post some great times at the track given a good launch, but i really think a different cam could of done better.

If hes happy more power to him, ill be the first to admit i always wanted a 847 mainly due to these responces it gets when someone puts one in and the lope is pure sex.

 

It sounds like the heads may be a bit suspect, but like has been said before dyno numbers are just numbers...Those who know me know that I laugh at dyno numbers...Dynos are for tuning and the track is the ultimate judge...The 847 would not have been my first choice for a cam, but if the car runs nice and the tune is good, then have fun...I remember when I posted my whopping 375 rwhp numbers I was just about laughed out of town...Then, when I posted my track times/mph I was some sort of hero...

Bottom line is that if the car feels good, have fun!

--Alan

 

I didn't have my laptop hooked up so I couldn't tell you what the knock was. 93octane fuel, and 275/40/17 Mickey Thompson DR's on 17X9.5 ZR1's with 20PSI HOT in them.

 

flow #'s:

lift - intake/exhaust
.100 - 71/64
.200 - 141/119
.300 - 201/149
.400 - 233/174
.500 - 254/188
.550 - 262/194
.600 - 266/207

 

On a side note, I agree with everyone. I was also expecting more out of this combo, but you get what you get. All I can say is that is seems to be running strong, so I have no clue where it is loosing power.

 

if i dont make 400 rwhp with my 355 and 847 im going to kill myself... but like said get it on the track and see what it does! thats what matters!!

 

Can i have your car after you kill yourself?

 

I have LS7 lifter set to 1/2 past 0 lash. Stock replacement lifters I set at 1/8-1/4 past 0 lash.

 

I was just thinking that this dyno is pretty new to the shop, they only had it for a couple weeks maybe a month... so I used some hp calculators from et and mph to get an estimation. Using ET I come up with 377rwhp and using MPH I come up with 382 rwhp... so maybe something is not set up correctly on the dyno yet, but who knows. I'll try to get to another dyno here in the next couple weeks.

 

just an example, my old cam only motor (stock heads and cc305) put down 325 dyno. But in decent air the car ran 11.8's all day long at 114 mph with a race weight of 3600 lbs.

I have a good friend of mine here in NJ that just built a 94 v6 car into a bad *** LS based drag car. He dynoed 479. Took it to the track and on his first time out it ran 9.91... now tell me how much dyno numbers matter.

I know guys here on this board who have dynoed 480rwhp+ but can only muster up a 11.80 pass. Then all you hear is the list of reasons why... my tranny was slipping, my knock retard was too high from the rockers, the track prep was not good, the clutch was slipping, the red car in the other lane was so slow I thought I broke... blah, blah, blah, blah!!!


There are a ton of little things that can cause your numbers to be low. Running slicks on a dyno, unlocked converter, big converter, bigger rear, ignition system interference, physically how the car gets strapped down can even make a difference. Dont sweat the numbers. I'm in the same boat as ABA383. There were a ton of people intrested in my new motor build up. My car did not dyno well, nobody even cared when I posted the numbers. When the car runs 10 this summer people will be all over it. Isn't the internet fun?

Use the dyno as a good place to start and forget about all the "your numbers are low" stuff. Go have fun with it, sounds like you built a pretty good combo that should put a smile on your face every time you hit the gas! It will blow the doors off of 90% of every thing you are next to at a street light!

 

did u dyno on dragradials??