'94IDITurbo7.3
HAMMER DOWN!
Ok... Got on the Dyno at Erics in Enumclaw tonight... This dyno is a mustang, and we were really unsure on how it was going to read compared to the Dynojet at Dynomite, I dont think any of us had any idea how things were going to stack up tonight...
I hit the dyno first out of the bunch, and I had every intention of milking my time on the dyno to get my setup to a tuned state, as I wasnt too happy with what it had put out on the Dynojet that day. By the math, my 7.3 should be flowing right around 71lbs/min at 30 psi, which comes right out to about 375whp/750wtq using commonly figured numbers for what a diesel puts out hp per lb/min (Right about 7hp/lb.min for our trucks), and thats on fuel only.... I had knocked out 342whp/(694wtq calculated based on my previous curves) on the Dynojet with Water/**** totally untuned... Without water/****, I put down 312whp, untuned...
Tonight, my first run on the dyno was 292whp/703wtq, completely unchanged from the previous dyno day at Dynomite, fuel only... That means the DJ was running 20hp higher than the mustang we were on today... Much like the first time I was on this dyno, that number wasnt going to do, so I started turning the wrenches... First thing I did was unplug the WG, and it didnt make any difference... Same numbers (Give or take a few)... Then I advanced the timing about a degree... Nothing... Then I lowered my fuel pressure... Numbers were even lower (280's I think)... Bumped the fuel pressure back up and plugged my WG back in...started gaining (Above 300 at this point)... Then I started adjusting my Gov stop on the pump... Didnt notice much difference (My pump flows 180cc's at ~4k RPM)... Adjusted my fuel pressure to 10psi (NMB2's suggestion) Pump jumped a huge amount, 20 or so whp... I had Syndiesel in the front tank to try, and I had been running on that so far... Brandon (91Dirtydiesel) had a theory that it was hurting, so I switched to my back tank and ran reg diesel.... Numbers jumped to around 340whp, Fuel only.... Then I decided it was time to try my **** setup out.... I had three bottles, one with straight water, a std window fluid bottle, and a window fluid bottle emptied enough to fit 3 heet bottles in (~50/50 mix).... I tried all three out, and not one made a difference (they were all within a few HP of each other)... I found this weird because I had gained 30whp on the DJ with window fluid... It was what it was... several runs, and no change.... Peaked out at 342whp/759wtq... This was weird, because my torque is HUGE compared to my HP, and compared to my previous curve....Tried some 5th gear runs, and they all failed because I would just blow my clutch out...
So we started looking at the curves, and laying them over the top of each other...
I noticed that my HP was peaking at 2200RPM, same as my torque, and then going totally flat.... Thats not right, because my previous peak was 2800... NMB2 got his truck up there, and then I could compare a truck with the same cam... His peak Hp was right at 2800 as well...
So There was a lot of speculation on why my truck laid its numbers like it did, everything from the IP/Gov, to the Turbo maxxing airflow out, to the Lift pump not keeping up... Either way, something was off...
I came to the following conclusion after driving home and thinking real hard about the issue... (And boy did that 50hp/60tq I gained make a difference, just shreads the clutch from 2200 on, and still feels faster)
Basically I think the problem with the HP curve was simply the fact that my IP was being starved of fuel, not because of the lift pump, but because of the Deadhead regulator and/or the factory filter head... I came to this conclusion, because everytime I bumped the fuel pressure at the reg, Id gain a little bit on the dyno, but the curve would stay the same... Basically limiting my max fuel input to the IP because there was a restriction inline before the IP, but after the lift pump... I had enough to reach my peak torque at 2200RPM, but not enough to reach my peak HP at 2800RPM... So I had a huge 759wtq number, but a HP number more fitting at 2200RPM on the HP curve, because there just wasnt any fuel to get me to 2800RPM... Had I got there, Id be somewhere between 380-400whp...fuel only.... Thats using Mine and NMB2's curves to calculate... Who knows if W/M would have had any effect at that point, we can only guess...
Bottom line, my truck needs some more tuning after I upgrade a few things, number one the clutch, and number two being the Fuel system... Im going to a single tank with a walbro 255, regulator, dedicated return, and Filter setup... Once I can rule those out, its game time, and Ill get on this dyno again... Also going to drop my stage 1 cam in just to see how it effects everything....
I guess to sum it up.... using my Torque number as a guide... This is simply a near/right at 400whp truck, provided I can get some more tuning in here in the near future...
Anyway, Ill get some graphs posted tomorrow... Im tired... And off to bed....
Its got to be the regulator, pump flows more than enough (@2200 RPM, my pump is flowing 22gph WOT), I was thinking a lot about that during the day today. Ive had these style regs apart before and modded them to work as a bypass, but as a deadhead, they just dont have large enough passages, and I think that the extra viscosity of the diesel is having an effect on the inlet valving in the reg. There really isnt any other reasoning behind these graphs... You can see at 2200, my tq peaks out, and then topples.... HP, runs right up to 2200, and then falls flat til the curve starts falling off... This is where it would hit 28psi, hold, then drop. I included the curve from last december on the same dyno just for comparison, the only things changed from that dyno was my pump and intake manifold, rest is exactly the same.
You can see from the graphs, when I fix this fuel supply issue, its going to be a monster... 7.3 PSD's with this sort of Tq@RPM throw down in the ~425whp range... I might be a little less just because of the IDI design, but we wont know until I get it fixed and back on the rollers...
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The three runs are the following:
Last december-(Turbo CAL setup, stock tires ETC..) 234/477
First run yesterday (No changes- RD4, 35" MT's) 292/702
Last Run yesterday (Around and hour of tinkering/tuning) 342/759
Tomorrow, I think I might tinker around with just running the pump right to the filter head just to see if it solves the startvation problem, but I dont want to run it like that... 14psi transfer pump input is too much... my pump is calibrated@4psi, and the spec is 4-8psi input... 10 is OK (Probably completely unecessary if I delete the reg restriction), but 14 is too much... If it ends up fixing the issue, I will add my fuel system to the list of next to do... I already have the tank and the pump has been sitting in the top of my toolbox for about 6 years... All I need is the filter setup and reg, which is all in-stock local... Probably a solid day or two worth of work...
Anyway, Ill report as soon as I know how this thing reacts to pulling the reg...
.........
Yahoo! 
