I was out visiting PDR today.....

[BushWakr - RIP]

Hi Guys,



I was out visiting PDR today and my younger brother was there.

He drives a 92 5spd.



He just had an HX35 put on, ATS manifold, full 4" exhaust and a bit of "driveway tune up" in my driveway last week.



He did 332 RWHP !!!! not bad



Ok, so I figured what the heck, give it a try. Since BD days were I did 283. 6RWHP I have eased back the fuel screw about 1 turn, tightened up the AFC spring and starwheel almost off.

I did a 325. 9 RWHP. . bonus!!

Not only that but my max temps at BD were right up there at 1700*F :--) :--)



Today, when mark ran the dyno, I never broke 1400*F.

Must be due to less fuel, a new HX35/16, ported manifold and holding my tongue just right.....

More to come yet...



OK the great news is... ... . On Fri last, Piers ran his new engine on the dyno. He was running stock 370's, small DV's, and a test twin setup... ...

His first run hit 694 + RWHP on #2 only..... SWEET !!!!!



You should hear that thing scream... man his open house is gonna be some kind to smoke tornado... pity the guys on the freeway 100' behind his shop as they go by.....



Pastor Bob,

Our Lady Of Blessed Acceleration Church.

With a new parish opened at the corner of 'Second and Stompit'.

 

[Jim Fulmer]

Piers..... He was running stock 370's, small DV's, and a test twin setup... ...



I know... . I'm running the same 370's and DV's but with a less efficient set of Twins and he just went right past me... . so did another 12V.



Jim

 

[RDusch]

Buswackr,

Is this a different type of dyno , Dynojet type, or loaded type, than you used before? and are you dynoing in overdrive or direct?

or have you checked both ways and does it make a difference?



Just curios, i ran mine on a dyno jet in overdrive, thinking maybe that was'nt the right way to go ... ... ... ...



OH YEA!! one more thing ... ... ... ... . your killin me 325. 9 SHWEEET!





Rick D

 

[Withers]

Way to go Bob, I mear 115hp and I got ya!!!!

 

[formula]

Originally posted by BushWakr

Ok, so I figured what the heck, give it a try. Since BD days were I did 283. 6RWHP I have eased back the fuel screw about 1 turn, tightened up the AFC spring and starwheel almost off.

I did a 325. 9 RWHP. . bonus!!

Not only that but my max temps at BD were right up there at 1700*F :--) :--)



Today, when mark ran the dyno, I never broke 1400*F.

Must be due to less fuel, a new HX35/16, ported manifold and holding my tongue just right.....

Let me see here... ..... and additional 42. 3hp with less fuel. Whasup with that? As for the EGT's... ... how long was the run?



Sean

 

[BushWakr - RIP]

Sean,



I'm convinced that drive pressures and incomplete burning of the excess fuel was the reason for this.

I did some extensive porting to the stock exhaust manifold, inlets and outlets, then ported the inlet of the 16cm housing. Used a cyl hone to clean up the exhaust housing OUTLET to the downpipe.

Modified my starwheel a bit more, some "tuning" to a new cone.

My fuel screw is now roughly 1 turn out from the BD day.

On the BD run, I started starving for fuel and my fuel screw was at the point were it was a bit hard to turn due to bottoming out on the internal lever. The runs I did yesterday did not once starve out on me. My boost is down from the BD runs as well. I was pulling 40-41 psi empty on the highway and hitting 1600*F on a WOT run in OD. Now, I just make it to 1400 at 100 mph @36-37psi.



I had a high RPM of 3400 on a couple runs, with the majority in the 2800 RPM/320HP range.

The higher RPM runs lasted a full 15 seconds (roughly).

The dyno itself is called Dyno Dynamics. It is a load dyno and can handle up to 1000 HP if I remember right.

It's out of Australia.



Bob.

 

[formula]

The end result of any of the mods you do to your pump is the travel of the control collar. Back off the fuel screw, loose a bit of travel... ... ... grind on the control cone and gain a bit of travel. Since the pump did not starve for fuel and fall on it's face, it would appear that it isn't flowing as much fuel as before. Obviously, the tight starwheel setting will hold off most of the fuel untill boost builds on top end. This will also make egt's rise slower. Changing from a 14cm to a 16cm housing isn't much of a jump, but it does work nicely I'm sure the porting definitely does good for efficiency. But it doesn't appear to add up to 42hp. How many other trucks with known previous dyno runs and no subsequent modifications have run on that new dyno for a baseline?



Sean

 

[BushWakr - RIP]

The guys I know who've run on it hmmmm... nascar mark, harry (pdr employee 1st Gen) my brother and his 92, Piers, are the one's I know personally that have run on it.



I also suspect the BD run(s) were not quite right, but I don't know enough about setting up a run properly so I can't be positive on that point.

My first run was 297. 6 but there was a problem sync'ing the RPM/speed. A few adjustments and I had a high of 350 hp but that was false due to my transmission trying to downshift into 2nd at 65-70mph... the decoupling and pause that resulted from the incomplete downshift, then the resulting re-engagement of 3rd gear caused a spike in the HP figures.

I made a few adjustments to the throttle valve cable and did about 4 runs in/at 317-322 hp with my final being 325. 9 at roughly 2350 RPM.

I'll scan it in and post it if need be. .



Bob

 

[BushWakr - RIP]

Matter of fact. . here ya go. .



edit: also, there are a couple 'O three more modifications I'm going to try running in near future. I hope to have my run AND my brothers run closer to the 400 HP range by the time PDR's open house day comes in Sept.

Randy is installing a new/updated nv4500, SBC clutch in a week or so, and he should have a better connection which started to slip after we did some driveway tuning.

 

[formula]

Go ahead and post it. But I'm not arguing that the dyno sheet does not say the hp that you claim. Rather, how the aforementioned mods and dyno produced that number. Did the other trucks produce similar baseline numbers to their previous runs on another dyno?



Sean

 

[BushWakr - RIP]

Well, the only one that I personally know who had a few runs all in and around the same readings is my brother. . with his final and highest being 332'ish.



Now as for mine... I honestly don't want to give it ALL away at this point but ... ... ... ... not that it is a new miracle trick either, to be sure, just a bit of a different approach really... ...

After my runs out at BD I went back to looking at the factors involved in "how, how much, when, how fast" fuel is supplied to the injectors. I wanted to reduce/eliminate the fuel starvation potential, the heat which was nasty and, improve the overall performance in general to make it usable on the street.

The fuel screw, for example, assigns a given amount of extra fuel to the engine.

In that "extra" fuel is a larger portion of the increase going to

low - low/mid range.



I "removed" some of that extra fuel (via the fuel screw) and tried to find (thank heaven for a donor pump to autopsy) another way to re-assign extra fuel to the upper end only, without the drawback of the low end smoke/heat buildup etc.

The way I describe it is... ... the fuel screw sends, say, 70% of the total increase to the low - low/mid range, and the balance (30%) to the upper/WOT range. I wanted to find a way of "assigning" that extra 30% to the upper end ONLY, without ANY extra going in at the lower/mid range end. By way of a hint... . when you look at the AFC assembly the cone is not the only thing that can be tweaked to contribute to my "hairbrained" idea . Also the starwheel itself can be modified a bit to help with this. .



I made some internal adjustments and some physical modifications (including a new cone configuration/ramp) so that instead of using the fuel screw as the sole method of overall performance increase, I am using a couple different physical modifications AND adjustments to do the same thing.

I have reassigned fuel to the upper end pretty much exclusively, I have altered the RPM/Boost when it is supplied, and the rate of increase as well.

My results are now this,,,, my EGT's do not have a climb rate anywere near what they did before. (I ran my old turbo with the 14cm and 16cm to have a comparison). The EGT's do not reach the high levels they did before, the pump is not showing any signs of starvation. I hope I am doing far less damage/wear to the pump on a daily driving basis because the real hard work doesn't start till well into the throttle pedal.

I am seeing far less heat building up as the run progresses, and the "starting point" were the "fuel dump" takes place is high enough and it happens quickly enough that I can hit a bit higher HP without all the negatives...



Now your questions raise an interesting thought... . what would my numbers be if I cranked the fuel screw right back in to the "bottoming out" feel position...

This is with the Lucas injectors BTW, not anything larger than that. Last, I am not using any "electrical" assistance on these runs because that mod can't be used on a continuous basis on the street without serious pump failure as you probably know. .



Bob

 

[formula]

Mostly top end fueling... ... . with boost... ... . who ever heard of such a "hairbrained" idea :-laf Where's the smoke? :{



Couldn't resist Sounds like all the tweaking has yielded many positive gains. Would be good for towing for sure. But, I've got another wrench to throw at ya... ..... Could you do a run on the PDR dyno in which you hold it WFO for a longer run and see what the hp curve looks like? This is in regards to the fuel starvation condition as it seems to require a bit more than a quick blast to take hold. Also, what are your thoughts on the cause/effect of said fuel starvation? I haven't ever experienced this on the street, doing long burnouts, on the dyno, towing my trailer, or any of my other "hopefully there's not a cop around" driving habits.



Cheers,

Sean

 

[BushWakr - RIP]

On the dyno runs, mark thought that I'd have no starvation problems because I was not into high enough RPM.

During the runs we did to calibrate the dyno, I had 3 or 4 of the runs hit 3400-3450 RPM's because of insufficient loading... . No starvation.

I think part of the reason is that on the upward curve of the run I am not drawing down on the fuel as much/as fast, making it less likely that I run dry which, maybe helps the lift pump keep up.

I'd bet that if I ran the fuel screw all the way in to near runaway I would have signs of drying up... .



Starvation is nasty too,,, look at the second gen VP pumps, they pretty much seem to die right then and there, or soon after.

Since our pump relies solely on fuel for cooling AND lubrication it's not hard to see the damage that can be done.



During one of "procedures" on the autopsy pump I removed the gov. counterweights and the plunger. The fit is incredibly close. Even the slightest attempt to pull the plunger backward resulted in building a vacuum in the fuel chamber (my word).

Any dirt particle, lack of lub or loss of cooling would be seriously damaging to those kinds of parts/tolerances.

I always ALWAYS run an additive of some sort now... since we are pushing these pumps pretty darn hard it can't hurt.



As for the dyno run and checking the hp curve... I have more to do yet... both on mine and my brothers truck. We need to ration our use of the dyno time and $$ to only when ready sort of thing. .



When the first few runs were going on, we could see what looked like an instantaneous drop in HP for just a fraction of a second, immediately followed by a significant jump upward in HP. .

We thought that perhaps the truck was trying to shift down to second gear then immediately jumping back to 3rd.

I have not seen any sign of that behaviour on the street. I can run the thing from about 50 mph go WOT and pull all the way up to about 80 mph for the OD shift. (I'm bringing that downward because it's too high)

I am wondering if the sudden jump in fueling is either causing that to happen or maybe the sudden dump is just making it look that way, the symptom was noticable both on the dyno and in the cab when it happened.

We just sort of looked at each other... .

Anyway, I still need to do some fuel pressure checking and other stuff too.



edit: Oh and if all this isn't enough I recall mentioning in one of the threads that the governor spring was overriding the load/RPM governor circuit, at least to some degree...

Well I think that some of the "oddness" that I'm seeing is partly the cause of the gov. spring change.

Man it' going to be alot of work/tinkering/fiddling to see what effect that thing is playing in this... .

My brother's runs will be a good baseline because I haven't put the GS in his yet. .





Bob.

 

[BushWakr - RIP]

Ok, here's a bit of stuff on the dyno being used at PDR... .



It is "new" here sort of... as in from Australia.

The dyno functions as a dynojet primarily. It has the ability to function entirely as a "load dyno" or mustang type.

For diesels, it should be able to handle up to 1300 HP and for other applications, up as high as 1800 HP I think Mark said.



Now my brothers numbers are actually in/at the 220 RWHP mark.

They've been testing various "loading rates" to establish a repeatable, consistent method of comparing HP between trucks...

For example, on our trucks the "ramp" speed or time/duration of the run could conceivebly be longer than on a truck making 700 HP because of heat generation... . just as an example.

The dyno has sensors for monitoring inlet air temp, humidity, ambient temp, barometric pressure and what ever else... as others do I'm sure...

It uses these "inputs" to maintain a "steady state" of correction during the entire run and series of runs as well.

Mark set the "ramp" speed for my run as well as my brothers at the same level as used on his own truck and harry's as well.

Using that ramp speed we ALL had very consistent results with high HP being only slightly more than the average of a number of runs. When the ramp speed used for high HP trucks was used (quicker/shorter run) the HP numbers went off a bit. On one run, I hit 350'ish. I DO NOT claim that since it was the same type of result when done on my brothers truck as well, that is higher HP.

The 332 HP was the result of the faster ramp speed on Randy's truck and the 350 was the result on mine.



I'll leave the door open for mark to correct anything I'm getting wrong here...

Prior to my final 325. 9 run I had 3-4 runs all in the 318-322 range .

My comparison run at BD was the Mustang style dyno. .

The two types (mustang and dynojet) will show different results, partly due to correction factors used as I understand it. On this dyno the correction is constant state. It even calculates/compensates the potentially lower HP numbers due to repeated runs and heat generation... or something like that. . Like I said mark will fix this if I'm going off course here.



Now I'm not an expert in dyno's, in fact I've had 3 runs total on BD's and about a half dozen on PDR's new one.

One of the things I really like about this dyno is the way the truck is secured... . It is impossible to break traction on the rollers... the harder you pull on it, the harder it holds you down...

Like I said above I have limited experience on these things so maybe other dyno's do the same thing, but it is pretty cool to watch an "as close to 700 RWHP" drive on and run without extra weight being needed or anything else...

BTW, does anyone know the formula for calculating "T"??

I did not get a torque value on my runs.

My hp was 325. 9@2250rpm.



Today, I did some test runs to see if I would experience starvation... I had no problem right up to 3500 RPM either from a standing start or a moving start. It's also running about 95*F and 85% humidity around here too... I did see some rough idle after a few runs which, I think, Power Wagon theorized was due to heat build up in the pump resulting in "thinned" fuel... ???? I don't know enough to judge that theory as valid or not... but it happened.



I'm going to do some more work on the pump and see if i can repeat the starvation conditions and/or what it takes to get me near that... don't wanna bag the pump, even if it is a good cause. .



I have a couple new (to me) mods to do on the truck and I'd like to see what the results are in HP gain/loss. I'll also try to do the comparison like you mentioned Sean... that being the hp curve and any variation at the upper ends.

As it is right now,,,, If I go WOT in 3rd I can run like that pretty much all day and not get into danger with temps. If I use OD, then that is different. I can eventually climb up to 1450-1500*F.

To be fair though it's darn hot around here right now, but it hot in the desert areas of the states too... and more often than here... so I don't know if this is a "towing" option. .

Need to do some testing I guess...



Ok that's it, now I gotta go to church and say 10 male hairies...



Bob.

 

[JVanvuren]

Originally posted by BushWakr

BTW, does anyone know the formula for calculating "T"??

I did not get a torque value on my runs.

My hp was 325. 9@2250rpm.

I think that works out to be 760. 7 ft lbs?



Torque = (5252 × HP) ÷ rpm



Page with lots of good info, formulas, etc: http://www.grapeaperacing.com/GrapeApeRacing/tech/miscpower.cfm



Hope this helps



John