I have a 385 with a pretty big cam. It is rated to make 500 HP at the flywheel by Trickflow. I used their heads and cam, and they recomend to use a holly 750 DP and an edelbrock Victor Jr. intake. So I did.

I got the car Dyno tunned a month ago, and it made 341 TQ and 350 HP at the wheels. Whats the deal? Any suggestions?

It has a Moser 12 bolt and a T-56 tranny. I was expecting to lose about 100-120HP due to the drive train. But I am not making it. The Dyno guys say that the motor sounds real stong and that they didn't think the motor was going to be so powerfull. They said it must be making around 410 at the fly. But that is still way down of what Trickflow advertises.

Am I just a chump for believing them? Or what? Thanks for any insight....

Also the car is still being built sorta and I have not even had a chance to try different spacers or anything at all.

And the exhaust is big. dual 3" into a single 4" and a sinlge outlet.

 

Did you actually tune the thing or did you just slap everything on there and dyno it and go home crying...?

Sounds like its time to get that carb dialed in and find some good timing. that should easily be worth the other 50hp your short!

 

The only way you're going to know how much power the engine itself is making is to remove it and dyno test it.
An engine is tested on a engine dyno in its raw form. No mufflers, no power robbing accessories and controled tempetures. What you actually end up with at the rear wheels can sometimes be a real eye opener. There are a lot of reasons why the power reading shown on the chassis dyno appears low.
1. the motor is not making the power it should.
Some internal problem, something about the build spec is different than TFS's combo. (compression ratio, headers intake port match, valvefloat etc Air fuel ratio etc.) The airflow entering the motor is too hot or turbulent.
You can bet the TFS rated power of the combo is tested under ideal conditions.
The engine driven accessories are robbing more power from the motor than you thought. making the net output, less.
May have to slow down the accessory pulley drive ratios.
especcially if the motor makes peak hp above 5200-5500.
When the accessories are overspeeded they really can suck the power.
The exhaust system even thou it is big, does not agree with the motor (camshaft profile etc). May or may not have to rethink things. may need a major redesign or just a minor tweek.
The chassis dyno test method loading, rpm increase test rate was such that will give low conservative numbers.
The test method does not duplicate the engine load and inertia (acceleration rate seen by the motor when the actual cars would be accelerating making the numbers not jive.
You need to go back and look at the details of the actual engine build. What the actual specs of the motor are not what they are supposed to be. (Compression ratio)
if the motor is actualy 9.4:1 when the spec calls for 10.25:1 the motor will not make the power its speced out to.
If the motor's cr is too high (for the fuel) causing detonation, them motor will not make the power it should.
The camshaft could be installed wrong or ground wrong, Cylinder to cylinder varience, or just the wrong grind. ( happened to me.) A faulty valve spring allowing valve float on 1 cylinder.
Your headers are not the same as the ones in TFS's design spec. Can make a big difference. Your "Y collector" may be all wrong for the motor. It's criticial.
The motor may just need jetting and timing setup and dialing in.
May have a simple ignition problem. (cross fire), ionization in the cap, bad spark plug, wire, coil, ignition box fault etc etc. Bad ground.
Have you track tested the car yet? The proof is in the pudding. If the car ET's and MPH's as it should for a 500bhp motor in X weight car, don't worry about the dyno numbers.
Have you done a simple compression test or leakdown test?
What are the actual parts that make up the 500hp "receipe" ? What parts did you substitute for others?

Not sure if I'm looking a the right flowbench test for your heads but the 195cc 72chamber "CNC" heads only flow 249CFM. Capable of 515hp max. ( 12.5:1, race camshaft ideal conditions etc etc yada yada yada).
On a motor with 10:1 compression the numbers indicate that the 10:1 engine combo will make 463 hp. Not 500. Even the best flow test shown (258cfm) indicates a best power potential of 530hp or
about 479hp on a 10:1 motor. Not 500.
I don't see 500hp in their combination. Unless I'm looking at the wrong heads.
Which heads are suppossed to be used in the recipe? What heads do you have?

 

You dyno'd it a month ago, and now you're posting? Why the delay?

Anyway, did you just do 3 pulls, or did you tune it there? Did they measure the O2, and timing, and make any adjustments? Any suggestions to get more power out of it?

Are you running V-belts or serp? You could remove PS and ALT for a pull if you want to find out how much you're losing for those. I'm thinking along the lines of paying for 2-3hrs of dyno tuning, and play with some of your "modifyables".

carb spacers, etc are also fun tuning tools. If you have a chance to get a few hours on the dyno, i'd bring as many bits as possible to try out, if you can borrow a spacer from someone, etc. Carb tuning kit....

 

was it a mustang dyno or dyno jet/chassis dyno? mustangs i heard read lower

 

Wow, well crazy amount of responses. I love it. Ok let me answer a few things real quick.

It is only running an Alt. 1 V-belt, thats it. No PS.

Ummmm... New plugs that all look good, and there is still no IGN box, as the one I got seems to not be working totally right, so it is just running off the dizzy.

The heads I am using are the Kenny Duttweiler, that are CNC ported. I know i miss spelled his name, but if you go the TF site, they have all the specs there.

http://www.trickflow.com/product/che...r_23degree.asp

With that said. If you look in a summitracing cataloge, they have a section with trickflow cams and stuff. Where they claim to have been using the selected cam, heads, vic. jr intake and a holly 750 DP. so thats exactly what i did.


With all that said, I am not retarted, or stupid, not that you guys are saying I am, but I am very aware that the #s are for a PERFECT motor set up. And that my car is not set up the same way, i.e. exhaust, temps and all the like.

As for the delay, one word, COLLEDGE. haha. Studying to be a Mechanical Engineer takes every minute out of my day, I do all my work on the car on breaks, even my weekends are full. Esspecially with the gf taking up time too.

Now that you know I have no free time. hehe, please help. Do you think I should just try spacers first? or what?


The dyno shop didn't do a lot of playing around, just jets and making sure she didn't run lean at any point kinda thing. Smoothing her out, thats all. They didn't really have a GOAL, they just got her running and out the door. The only thing that I have on there that Trickflow didn't is a 1/2" open spacer and my 3/8" N20 plate.

Thanks for all the help guys, I will check back and try to answer as much of your Qs so that you can help me with mine.

I have hundreds of pics of my car and pics of the dyno sheet and all on my CD site. Please check it out, and if you don't wanna kill a lot of time just go to the last page. THANKS AGAIN!


http://www.cardomain.com/ride/782913

 

probly gotta mess with the tune...but not sure if that will make up for the 50-60hp that you are down

from the dyno graph it looks like the motor is flatlining at 5500rpms and holds that way till around 6 and drastically starts fallin off. possibly fuel starvin? maybe your valve springs arent a good match and are floating a bit...not able to carry the cam up higher in the rpm range where it wants to make power

 

Yeah, I know its the tune. I meen I think I am going to play with the spacers and maybe play with the carb a little. Thats pretty much it. If i make some more power, then I do, if I don't I don't. I am not super critical about getting those extra horses. Esspecially if they are WAYYYYYYYYY up there in the RPMs.

In the end this is purley a street car, and gonna be more of a DD, sorta. So I think I am gonna spend more of my time playing with the N20 and getting used to that.

 

There ya go, it wasnt properly tuned....


Get that baby tuned properly and you shouldnt have a problem finding that 50 or so hp

 

u'll definately want a tune in order before u start playin with that nitrous

 

Well I think the dyno shop did a great job tunning it. I just think there is probably more in her if I do "modifications" not just tunning. I mean, they made the stumbles and bogs go away. She idles SUPER low now, makes the car sound great. Sitting in the drive way, I idle at like 550RPM, sounds real mean. Revs up great and doesn't stumble at all on the way down. I am confident that the tune is more than suitable for playing with N20. Again, I am not going to be playing with more than a 100 shot. This is a street car in the end. Just there for the once in a blue moon kinda thing. Maybe someday take her to the track.

But thanks for all your advice, in the spring, when I have $ again, I will buy a few different things, and head back to the dyno.

 

Just a quick thought. Was the cam degreed in when it was installed? If it was 6-8* out I bet that could cost some power, maybe not 50 rwhp, but some. The A/F ratio looks fine. Maybe check the cam and also see where the timing is set.

 

what was the a/f and timing like. itsalmost like you have no secondaries on the carb. also like what the guy above said.. make sure the cam isnt a tooth or 2 off. that could seriously kill power.

 

well power is def not being KILLED. Just slightly lower than expected. The cam was not degreed and I am not sure what the timing is. I don't have time till the spring to do any of that stuff. I will just make a list of the things to check in the spring and then I will run down them, making sure that everything is optimal. Hell it could be that the motor just MAKES that much power and thats it. But yeah, I will def check all that stuff. Thanks again.

If anyone has any other idea, please chime in, thanks.

 

Remember that those "advertised" numbers are for an engine that is ABSOLUTELY IDEAL IN EVERY WAY; with no compromises whatsoever of the type that might be required by a car chassis. Perfect exhaust (long tube headers, probably carefully tuned to the motor in question); perfect air intake (velocity stack, ambient temp air, no filter); perfect fuel (??? who knows); no alternator, water pump, power steering; the thinnest possible oil; low-tension rings; every engine-building trick known to man; and so forth. IN NO WAY representative of what the IDENTICAL same motor would do once it's actually IN A CAR, let alone what a motor built out there somewhere in meatspace would do. Don't forget, all theirs had to do was to make ONE dyno pull, and then that number is then etched in ad-copy concrete; which is also quite a bit different from the real world. For all you know, that test mule could have blown up the 2nd dyno pull, but you have no way of knowing that.

Personally I don't see where you have anything to complain about ... yet.

 

What was this thing dyno'ed on? What kind of Dyno?

If it's a Dynojet or other inertia-type dyno then yes, you're probably down on power. If it's a Mustang Dyno or some other type of dyno that actually puts things under a load then you're not doing too bad.

"350HP" is a number that hangs in mid-air. Without knowing what it was tested on or without detailed knowlege of the conditions of the test the number is, basically, meaningless.

When I go to a dyno I don't worry too much about the number it spits out. I am usually more interested in things that help me figure out where my output is compared to a "known quantity." I often ask about stock LS1 Camaros and Dodge Vipers for comparison. For instance.... My Malibu laid down 390 to the rear wheels. So what? Well, the dyno operator then told me that stock 450HP Vipers have often laid down about that same numbers to the rear wheels on their dyno, but through a more efficient manual transmission vs. my old slushbox. NOW that 390 HP number has a lot more meaning and relevance, doesn't it?

If your dyno guys says he was "surprised it was so strong" I'd definitely take that as a good sign and drill him a little further on things. Ask him what kind of numbers he's seen other combos spit out for comparison. The dyno operator is often a fantastic source of information.

BTW- you ain't gonna tune 50 more HP out of that combo. I know the kind of tuning your guys did to the motor (jets and timing to get it in the ballpark) and it's probably pretty close. If you were down 50HP just becuase of the tune the motor would be OBVIOUSLY not running right. You can probably tune another 10-15 out of it but I've never seen anyone tune 50 more HP out of a motor that was apparently running strong to begin with. Not an N/A motor anyway- turbos, blowers and nitrous are a different story.

 

Damon: Thanks for the great advice. I never really thought about the comparisons. I am headed back there for them to fix a leaky brake line that they worked on, I will be there for a few hours. I will def ask the dyno guy what other cars/combos have done. I know they do a lot of stangs there and a lot of vettes. So I will def get some comparisons down.

As I said before the dyno guy was impressed, so that is a good thing.

From my understanding it is a dynojet, not that mustang dyno. So I am pretty sure that the #s are OK and not reading high.

As for the motor not reaching what it was advertised as, I know that I will never tune 50 HP outta this thing, but I will try to get another 10 or so. I guess when it gets warm out I will take it to the track and then I will really have some definative knowlegde of how strong the car is.

As for the tunnig that they did, it certainly sounds like they did a good job. Car runs great, turns right on, no stumbles at all, and revs right up and down with no hesitation. And that is without it even being up to temp. Once that happens it gets even better. So I don't think degreeing the cam and doing all that will really gain me too much. If it was a race car, or motor, then I would see that.

But as I said before, this is just a street car that I am looking to squeeze a little more out of.

Then again it is ALL forged, so I can allways spray it more. They guy who built it says the parts are good for over 700. Then my weakest link is my T-56. If that snaps, then I am gonna have to get that built up too....

 

yeah just play with the timing and air/fuel to see what u can get out of it. i'm sure there is more in that combo. i would expect it to see alot more power than what it has put down so far.

 

I guess. I mean you have to remember that I am running a big 12 bolt, a 3" chrolmolly DS, and a T-56 that is attached to a THICK flywheel. I mean thick too. It is a custom piece due to the motor being a 2 piece rear main, and the tranny wanting to mate to a 1 piece. The extra inetia make it rev up and down real smooth though.