dankl

iTrader: (1)

Hello,

I was just at my mechanics the other day. They finally got my 418cid set-up on the dyno for a few pulls and a tune. The dyno showed a measely 450rwhp and 425 tq, or so...

I was expecting much more, however, I do honestly believe their dyno is low reading compared to most. When I had my LS1 with heads/cam/FAST 92/92 combo/etc... we only put down about 400 rwhp and 375 tq.

The new set-up definitely is a whole new beast. It's hard to keep the street tires on the ground. Going to have to put some DR's on soon. Car has so much low end torque though. Can punch it at 2,000 RPM's, no clutch, and light the tires up with ease

Anyone think I should be getting better numbers from a 418?

Compression is 11.1:1
Cam: 237/242 with over .600 lift
Heads: (Weak Point) Patriot LS6 stage II heads milled to 59cc
Intake/TB: Ported FAST 92/92 combo
Moser 12-bolt w/ 4.10's
Monster Stage III clutch
etc...

ndfrsd6

iTrader: (5)

well your heads are not that bad ...i had my M6 through 241's and a 90/90 setup i put down 500 and 469 and now i have a th400 and still put down 461 with a 5200 stall !

your cam is a little small though and what headers do your have 1 3/4 ?

dankl

iTrader: (1)

Yeah, headers are 1-3/4". The cam was spec'd by Pat G. I told him the car would be a daily driver, but plans changed and now it's not.

The cam I used to have in the LS1 was only a 222/224 with around .600 lift w/ 1.8 ratio rockers.

teke184

iTrader: (5)

pretty small cam for a 418ci engine.

i'm sure you'd pick up a considerable amount going to a bigger cam.

you could just about put that cam in a 346.

dankl

iTrader: (1)

I know that cam could be used in a 346. I didn't want to go with a huge cam, because I don't just want top end numbers. I wanted a cam with a great mid-range. The torque curve is amazing though. Comes on early, stays pretty flat, and pulls very hard.

I don't think going with a huge cam will help out that much. Obviously, I will get more peak HP, but that is not necessarily what I'm looking for.

Just kinda curious to see if anyone thinks the dyno is low reading. I know the only true test is to go to the track, and I will eventually. But when you see set-up after set-up posting results of 500 RWHP or more, and high torque numbers, I get a little depressed thinking about the $$$ I just spent to have numbers that a lot of people seem to get out of their 346's...

ndfrsd6

iTrader: (5)

well that motor should be in the low 500's for sure and still be an ok driver but like you said $ is the issue now a days

1QuickT-A

iTrader: (12)

Yes it should definitely be in the high 400's or low 500's at that cubic inch.. But, I would say the heads are a limiting factor and the cam for sure. I have a friend with a 383 with AFR 205's and TSP Giant Cam making 505rwhp thru a 6spd and 12 bolt. He drives it everywhere..

The guy that owns the dyno should know wether or not his dyno reads lower than most.. Not us. But, I could see your combo making low numbers especially with that cam and those heads.

My street car makes 435/390 "Cam Only" thru a T56 and 9"..

ndfrsd6

iTrader: (5)

you dont need big heads to make 500 hp i have 241's stage 3 granted but non the less and i grabbed the 500 mark but i had 1 7/8 headers and true duals

6.0monsta

iTrader: (7)

I'd say a 50whp/50tq gain over your previous setup with ONLY the cubes being the change is awesome. I vote low reading dyno.

dankl

iTrader: (1)

^^^Yeah, it shows I gained almost 1hp/1tq for every cubic inch.
I've been told by my mechanic that his dyno always reads low. He says they own one of the first dynojets, and claims the older ones always read lower than the newer ones for some reason.

All I know is that when I was a 346, the first mods I did were the heads/cam/exhaust and the car put down only around 390rwhp and 375tq, or so. I then added 1.8 ratio rockers and a Ported FAST 92/92. This got me all the way up to 400rwhp and 380tq.

It was then that I started asking him about his dyno and why my results are never in the same ballpark as others posting results on this site.

Back to the cam I have now. This was spec'd by Pat G. He actually spec'd my cam at 234/240, but when it showed up it was a little larger, 237/242 on the cam card.

I don't know why he'd spec me a cam that was so undersized. That is why I don't think throwing a giant cam in will show results that justify the swap. Hopefully it is just the dyno, but it still hurts everytime I think about that damn RWHP number. Car pulls like a freight train though

Quick Sh0t xMLx

I'm going to have to agree with this. The change in power seems about right. What kind of dyno is it? If it's a Mustang Dyno or a Dyno Dynamics I wouldn't worry about it. Take it to the track\

Edit: Nevermind you posted at the same time I did. I honestly wouldn't dwell on it for too long. Like I said it sounds like the dyno reads low(400 whp in a FAST/heads LS1, lol).

ndfrsd6

iTrader: (5)

yes what kind of dyno ? and +1 on the track ...

dankl

iTrader: (1)

It's a Dynojet, but supposedly an older dynojet.

Now that I think about it, I remember they were doing a trans-am right after I did my 346 modding. The trans-am went with a 228r cam (compared to my 222/224), PRC 5.3L heads (compared to my LS6 style), LS6 intake, and exhaust. His numbers were lower than mine. According to my mechanic, that combo did around 375RWHP.

ndfrsd6

iTrader: (5)

personally i would find another shop ....

red fury

iTrader: (1)

Like stated above the HP & TQ gains from the 346 to the 418 seem pretty good or on par. I bet the power in the mid range is great on the street. And as far as Patrick G, it sounds like he spec'd you a cam for a daily driver with great manners.... just what you asked him to do.

I may be biased, but I don't think your heads are killing your combo. They may not be the best suited for you setup but they flow very good. Tony Mamo posted up the flow results of some untouched AFR 205's and I compared those numbers to my PP 243 LS6 59cc Stage II heads. The result was that the PP out flowed the AFR's in the low lift areas and matched them at the .600 lift. I am sure I am about to get ripped a new one for posting that!!! Not the same flow bench ect.... And there is no way a PP head can step in the ring with a AFR ect... and yes I realize my LS6 heads have larger runners that the AFR 205's.

Man just enjoy that 418 and let it eat!!!

slow trap

iTrader: (22)

that setup i would think should be near 500 rw as mentioned. i agree with hitting up the track and finding another shop with a dynojet and strap it down and do a couple pulls just for peace of mind.should only cost you 50 bucks or so for a few pulls only.

dankl

iTrader: (1)

^^^If you can find me someone in South Fl who will do a few dyno pulls for $50, I'll go there right now...

Thanks again for all the input here guys! I'll try to get to the track to see what times I can pull.

Sales2@Texas-speed

iTrader: (5)

Track times will tell the tale, IMO. Dyno numbers after an engine swap are somewhat worthless without knowing the baseline numbers on the same dyno.