Whoop...... meant to say 7200 rpm.

 

Hey, it was nice meeting you and Scott yesterday. As you already said, that is definitely a strange looking dyno graph. I have no doubt that there is some untapped HP in there somewhere. Thinking about your combo on my drive home, I came up with a few things…
* Did you guys check to see if the monoblade was completely open at WOT?
* Has anyone checked all the sensor data? If not, I’d like to see someone look at all the readings to see if they are within spec.
* Being a high rpm stroker, you might want to consider some 1 7/8 inch LT headers.
* The only LT1/4 (intake) motors that I’ve seen making more HP than yours are solid rollers.

All that being said, it’s probably still the intake that is restricting it.
Good Luck

 

NO, YOU said pleanum, not plenum.

FASTFATBOY,
Contrary to popular belief... the added runner volume does help the situation in my motor. I was "told" that I would need to use the spacer/adaptor if I wanted the engine to perform as it should. Chuck was rather adamant about this.

On another note... if you figure in the extra runner that creates (they are direct extensions of my intake ports) it makes the head look like it's ~260cc or better. Definitely not hurting things on my end.

One thing at a time though Denny... otherwise you'll end up chasing your tail. IMO, the cam is fine. I wonder what it'd do with a converted Super Vic on it.

-Mindgame

 

I hear ya as we got a little rattled as we pulled every trick in the book tuning it and nothing was working. The injector issue was unplanned as the plan was change injectors, dyno, change TB, dyno and putting in new injectors was not in the master plan. I think, however we got what we are looking for and I did buy new injectors as three bad injectors out of 16 being they are new is not very good. Not much confidence.

We are going to let the dust settle for a bit and do a new game plan.

It was nice meeting you as it's fun being able to put a face with names on the list. We'll eventually figure it out and good luck on your project also.

Thanks for the ideas.



-

 

LOL yeah you got me there.

Yeah you made that power with those plates, and I'm with Chuck on that... I would be adamant about that too. They really helped... hell 1/4 - 1/2" on the LT1 runner would find some nice power... lots of work when 2" would do more... Then again racerdude realized that already with your intake David.

Bret

 

Quite a bit off the topic of this thread, but has anyone ever questioned those AFRs? To me, they do not appear to jive with the supplied fuel flow data.

 

Meaning?

 

Providing the fuel flow measurements are accurate, which I'm inclined to believe they are, I seriously question the accuracy of the posted AFRs.

 

How would you verify? The AFR reading is after combustion, so you can't just use CFM and fuel delivery to calculate it, or can you?

 

Because the AFR is a ratio of X#s of air to 1# of fuel, you can determine the #s of air using the CFM, air temp, barometric pressure, and moisture content as necessary factors to determine the actual weight of the air consumed. (I happen to get mine from a 'Machinery's Handbook'). You would then ÷ the given weight of air consumed by the #s fuel/BSFC burned in the same amount of time (minute). Of note, air gets lighter with increasing temp, AND also with increased moisture content. This is just something to put the answer that is derived, into perspective, when comparing different weights of air, as air 'qualities' change for any given day. Anyway....

As an example, at 80º F, 29.92 Hg. equates to .0736#/cu.ft. or 1# = 13.59 cu. ft. of air. This is with NO moisture in air.

As there may be some humidity in the air in the northwest, we could include an example of # of air with some humidity in it. I'm not gonna go into how I derive that at this time. The above factors along with addition of 90% relative humidity will equate to:

.0712#/cu.ft. or 1# = 14.04 cu. ft. of air

Willing to entertain anyone's challenge/dispute of these figures. I'm not infallible. HTH.

 

What did ya'll do to fix this problem? I'm having the same kind of issue it seems. 12.5 CR and a 255/263 duration came. I'm running a dfi system and still have the problem Everything I do to the inginition wireing seems to help though. I'm in the 455 rwhp range and it kinda flatlines too..then the cutting out stuff begins.

sorry off topic guys.

 

Switched my SEFI-8LO to inductive pickup mode (required sending it back to FAST) to work with an MSD crank trigger and bought a FAST eDIST to drive LS1 coil packs fed by the signal from an MSD Digital CPC cam sync sensor in the distributor hole (Hogan's intake).

None of this has been tested yet, however. The Digital CPC cam sync interferes with my firewall, as it turns out, so I'll be selling it and running a Jesel belt drive timing set with a front-mounted cam sync sensor instead.

 

An easier way to do this is run a Cran hal effect pickup, its plug and playfor the most part, no need to send the box back to fast.

 

My SEFI-8LO was sent back to FAST to be configured for inductive pickup without my knowledge and arrived that way with my engine, along with the Digital CPC stub, the FAST eDIST and wiring harness, and an MSD crank trigger kit.

 

Obviously I'm going to replace the intake........What did you have to do to get the Hogan intake? Are these basically an "off the shelf" build on order or did you have to send them your heads........ or what??

Also what did it cost?

I'm in a bit between a rock and a hard spot as I really don't want to go with an aftermarket hood but may have to if no alternative as I understand using a lower profile intake would not produce much in terms of power gains.