More Dyno Disappointment

[parchisi]

Bad news first, the car made only 430 hp on a superflow dyno. Was hoping for at least 500 but the guy said that my camshaft is holding me back, with a lobe separation of only 107 degrees, 20% of the power was goign out the exhaust because of too much overlap.

Good news is that it runs pretty well, a 100 hp increase is still quite a kick in the pants!, and the guy (who really seems to know his stuff) told me that with a better suited camshaft (about 114 degrees of separation and more lift), and the smallest pulley they make for my procharger, I could easily be making at least 550 RWHP.

So, it appears that I know what's going to be next, a cam and pulley swap. It never ends, does it?

 

[tjh566]

just looking over your mods, you need bigger fuel injectors and a bigger MAF, those are both too small for you application.

 

[Pokageek]

NOT trying to insult you or your set up but I am really perplexed...you were only making 330rwhp? now with turbo still less than low 5.0 n/a?

 

[Guero]

you mean S/C? not turbo

 

[Red1990Lx]

NOT trying to insult you or your set up but I am really perplexed...you were only making 330rwhp? now with turbo still less than low 5.0 n/a?

Say that again, I don't quite understand you!!!

 

[86bluecobra]

just looking over your mods, you need bigger fuel injectors and a bigger MAF, those are both too small for you application.

Yes I agree. Those all need to be bigger just for the N/A 408 let alone a S/C'd 408.

 

[BlackVert]

a good comp xe blower cam would really turn that thing into a monster. 114 lsa.

with your compression, i wouldn't go above 8# of boost. try the cam first and keep the boost low. i bet you'll be very happy

when getting a new cam, i'd also go to roller lifters. those link bar hydraulic ones are really expensive, so if the budget doesn't allow for them, at least get some solid roller lifters.

and +1 on the "you need 42# injectors" thing

the 75mm t/b may not be big enough anymore. it is fine for a n/a 408, but with a blower, probably not.

 

[BlackVert]

ot - one question about your fuel setup ... how did you hook the mallory fuel rails up to your stock lines?

 

[OrangeMustangGt]

you only made 330 with a 408.....whhhhhaaaatttt?

are you running stock e7 heads?

 

[reddy351]

Not to be splitting hairs but, he wrote "430 hp" not "330 hp". (Did he go back and fix a typo while I wasn't looking, or something?)

 

[Pokageek]

No he said the 430rwhp WITH s/c was a 100HP increase...unless I read that wrong..

330rwhp on a n/a 408 is very weak. Something is wrong. Unless I am misunderstanding. I was using the example where low 5.0 (pretty beefed up buit still) is putting out 450+rwhp n/a and he is saying with a s/c he is 430rwhp?? I am confused cuz you should be able to get a lot more power out of that engine. Did I miss something though?

 

[Red1990Lx]

No he said the 430rwhp WITH s/c was a 100HP increase...unless I read that wrong..

330rwhp on a n/a 408 is very weak. Something is wrong. Unless I am misunderstanding. I was using the example where low 5.0 (pretty beefed up buit still) is putting out 450+rwhp n/a and he is saying with a s/c he is 430rwhp?? I am confused cuz you should be able to get a lot more power out of that engine. Did I miss something though?

I'm with you now... You had me confused with your previouse post...

What is your Air/fuel curve like on the dyno...or did they not give you that... I bet you are really lean and to compensate, they ran a safe tune on it. I would be curious to see their chart if they gave it to you. But as stated above, most 408 are throwing down pretty close to 400HP+ N/A...

 

[tjh566]

My bet is the cam as stated, and that hes pegging the MAF Early in the rpms and the fuel injectors arent supporting that much power.

I would go 42# injectors minimum, might need bigger, probly a BA 2400 MAF, and a good custom grind cam

But that is alot of cash right there

 

[parchisi]

Wow, I come back and there's a lot of responses.

First off, my signature is wrong. I have Siemens Deka 60 lb injectors, a 90mm SCT Big Air 2400 Maf, and two Bosch in-line fuel pumps. The fuel system is A-OK

Pokageek, insult me all you want, because I too don't know what the hell is wrong with my engine. You'd think i'd be putting out 400 easily N/A, but nope. Maybe it has something to do with the fact this was the first engine I've ever put together and I did it whithout a whole lot of guidance, so maybe I messed soemthing up, but it does run and has run pretty well for about 4,000 miles now, just down on power.....

They kept the air fuel ratio right between 11.5 and 12 for the most part. Pretty safe.

Blackvert, I didn't hook up the stock lines to the mallory rails, I couldn't figure out a way to do it, no adapters or anything out there to do it, so I just ran some 8an feed line and 6 an return.

Like I said before, I think most of the lackluster performance has to do with the mechanical flat tappet cam, 107 lsa, and low lift ( .510 and .515) I'm gonna call a guy that the dyno guy recommended to get a custom ground Comp Cams roller camshaft. The guy also said that I could easily go with a smaller pulley and he didn't think I have a 10:1 compression ratio, contrary to what my engine guy said.

 

[Pokageek]

parchisi,too bad you dont live up here b/c there are a few good guys that KC referred me to. Between the engine guy and the dyno people, they can get things going pretty nicely.

I was going to go with a flat tappet like you but I went roller instead. That way I think I dont have to adjust the rockers every 15k.

Also, a piece of advice. Get that car n/a around 400rwhp b4 you go into the boost.. I mean, if it were me I would get it running right first. I really want to know why that monster is giving up 70rwhp atleast.

 

[parchisi]

Well, the since ideal camshaft for N/A performance is different than for boosted performance, I think I'm just going to get a good blower cam and go from there. Also, I didn't mention this, but right when I got my N/A dyno tune, my car started to die at lot at idle. A couple weeks later, I found a broken spark plug wire, and that solved the idle issue, so I also perhaps may have only put out 330hp on 7 cylinders.

 

[bimmertech]

have you done a compression test yet?

did you assemble the bottom end?

you def need a bigger cam---although yours is not small. it seems small to us cuz we are used to roller cam numbers, but solid flat cams do just fine with those numbers.

 

[parchisi]

yes, I assembled the bottom end, no I have not done a compression test. I take it that I probably should?

 

[Pokageek]

What size cam would you expert guys recommend? Say ..largest size vs an "I dont want a rock and roll idle but I want good power" cam...

 

[bimmertech]

yes, I assembled the bottom end, no I have not done a compression test. I take it that I probably should?

i would do a compression test---just to eliminate that from being a problem.