As always.....

I made it to the dyno today, and home again. So cant complain about that. As expected, I had blowby issues. Filled the catch cans with condensation on the way to the dyno ( circa 250 miles each way) and when on the dyno, filled them with oil.
No surprise given my rings/bore honing ( or lack of lol )

Anyway....spent a little time at first, pump fuel only, and got some decent results. Boost was a little erratic, but not too bad. But still the upper rpm's are having problems. We could get it to rev to 7000rpm, but it really didnt like it. Up to about 6400rpm was ok though.

383, TFS 225cc heads, circa 9.0:1 CR, 232/240 on 115 cam

Anyway...here was the results of pump fuel only. I guess I cant complain really all things considered. But I wish I had have used the bigger crank pulley now !!

Dynapack4000, power at the hubs. 850rwhp, and 750rwtq



So after that I tried 50/50 water/meth. ( I didnt bring any straight meth with me ) After first finding the push-on fittings leaking....I dropped down to a single 625 nozzle which did seal. The car ran like a bag of ***** like with this. Missfiring, and generally running like crap, and making no power.

Surely this is odd ? Intake temps on the dyno never really exceeded 70degF anyway, with or without it.

So gave up on that as a bad job....shouldve just stuck to 100% meth. But you live and learn.


Queries.
Why wont this damn thing pull hard to 7000rpm ? Timing at the top end was 18deg, and AFR's mid-low 11's

Then towards the end....AFR's suddenly starting going lean...like 13's. Fuel pressure was good, and inj pulse widths were good.
IDC's were around 92%, RCEng 73lb running 66psi base pressure. Max boost was around 19psi, although this did vary a little at the top end. Dropping off occasionally. Tightening the blower belt, and BOV's didnt seem to make any difference.

Ive no idea if it will rev on the road, as its been raining a lot here, so traction is impossible.

Next step is to pull the engine out, strip it...hone and fit new rings. Hopefully that'll sort the blowby problem.

As for the injectors....is it likely they could be going faulty ? Do the RC's like high pressures, and high IDC's ?

 

Depending on how old the valve springs are they could be floating causing it to not pull properly

As far as the AF did anyone check the FP on the dyno during the pull, it could be that your FPR is going bad and not building pressure properly causing it to go lean.

 

As I said. Fuel pressure is rock solid with boost. Magnafuel regulator.

The heads are brand new, only circa 1000 miles on them. Using a Proform tool when I bought the heads, I'd say close to 145lbs on the seat.
1.7 YT Ultralights, and Morel lifters. Preload might be sightly more than reccomended, at about 50-60thou.

 

Have you tried throwing a new set of spark plugs in it since you ran the meth, and what are your plugs gapped at? Bob

 

Spark plugs were brand new before I headed to the dyno ( so circa 250 miles on them ) NGK BKR8IEX Iridium, gapped at about 30 thou ( set at that out of the box, so I just left them at it. )


Car mostly ran fine with no 50/50 coil dwell 3200ms, pump fuel only.

Car missfired with 50/50 coil 3200ms

Car missfired with 50/50 coil 4000ms

Car ran fine again with no water/meth coil 3200ms again. We did mess with it for another 30-40 mins on pump fuel after giving up on the water/meth, and for the most part it was fine.

I normally run 3200ms, never had any issues before, with or without meth. These are not LS1 coils though, but regular inductive Bosch transformer style. It is the first time Ive used these plugs though. Normally used NGK PFR7B double platinums. Never had a problem with them, I just wanted to try a cooler set this time.

I was measuring AFR's just after the left hand collector. FJO Wideband, with NTK sensor.

Dyno was measuring AFR's just after me X-pipe, where I installed a boss for it. Theirs was using a Bosch sensor though. Dyno Wideband read considerably leaner than mine. Some 0.5-0.8 AFR in some cases.

EGT's in no 7 header tube never really exceeded 1500degF. Greddy gauge, with probe some 5-6" from the head.

Dyno operator suggested cam timing might be a reason it is unwilling to rev. Im not s sure.
Cam is timed at 0deg, which did appear to verify at 50thou lift as per card.

Exhaust is a DIY dual 3",with DIY X-pipe, 2 x Moroso Spiral Flows, then 2 x Magnaflow mufflers.


I'll try and get hold of a leakdown tester before I actually strip the engine, but either way I need to sort the rings sealing problem.

 

Poor ring sealing which causes oil to be present could be causing detonation, have you checked the plugs? Bob

 

I only got home late last night. I havent looked at the car since. But there will be road 250 miles or so on those plugs now.
So i expect any signs of oil contamination, will be long gone now. But you are probably right that it did happen.

There were no audible signs of detonation, with det cans attached to the block. Nor did the visual knock display working off the rear knock sensor show anything.

 

Any detonation or missfire will cause the O2 sensor to read lean up top, valve float will tend to to make things go rich. But that DC is pretty high, I assume your ECU wont run low impedance injectors? Low-Z injectors seem to have a lot better control at higher DC.

Mine peaks around 6500 and I have the same cam, drops off too but it will still pull pretty hard to 7300, runs best when shifted 69-7000. Thats some pretty decent power though on pump gas.

 

Like KP said, your making some steam on pump fuel. Have you tried splashing in some race gas for safety margin?

And yes, this cam on a 382 will peak in the nebiorhood of 6400-6600 depending on heads and intake.

 

Well I to am leaning towards an oil related issuer cosidering how you filled your catch can the spring might be fine for most applications I would think about shimming the springs up for a little more presure like in the 165-170 range if you can I don't know what your lift is so you would have to determine how much you can go because of coil bind etc... If you are floating the valves and there is too much fuel present it can also read lean. Remember a wideband is really reading the amount of oxygen present and too much fuel can cause that same thing, and since you said everything looks good on the fuel system (IE:presure and duty cycle) this is another possiblility to consider looking at. It was something I had happen to me a while back. Good luck with it!

 

Unfortunately my ecu will not directly fire low-z injectors, which is why Ive been struggling with these 73lb RC's ( 750cc ), even when I dont like them. Dont really want the hassle or expense of wiring a box in either, and buying some big low-z's. Although it probably is a common sense approach.

As of yet, I dont do race gas. Cost, hassle and various other reasons, mean I do not see it as a viable option. Unless perhaps for special occasions. So it isnt something I want to try...in case I do like it. Im way over budget already.

I'll consider shimming the heads when its apart. Cam is 595/608 with 1.7's I'll confirm what the springs can take, but I assume 0.650"
So I guess I could throw 20thou at them.


As for fuelling. 8 big injectors would be my easiest, and probably cheapest option. There are high-z available, although I am concerned about how they might perform at the low end.
My other option, is 16 injectors. I still have 8 x 60lbs here, so Id only need to buy another 8, and sort an intake with rails and plumb it up.
My ecu can do 16 quite easily, so that side of things is simple. So it might cost little more than some options, but Ive no doubt it will be future proof, and perform better than any 8 injectors will.

Im starting to think this might be my best option.

 

Id also appreciate feedback from anyone who has ever used a Dynapack before. The only other time I was on a dyno, was in June 06. Back then, once I hit 6000rpm....it was lights out. Which was odd.
On the road, 65-6700rpm wasnt a big problem.

Im wondering does the upper rpm struggle dyno related, in that perhaps its loading the engine up far too much.
It would be nice to have had some dry weather, so I could at least have a go on the road.

 

Never used a dynapack but read they read a little higher than a dynojet since the friction loss from the tires isnt present. But seeing how a dynapack works I'd assume the power curve will resemble the true engine power curve more than an inertia dyno. With an inertia dyno once you start spinning those heavy *** drums up I think its not unreasonable to think they may overshoot HP a bit RPM-wise at very high speed..

Just my opinion.

 

Anything Ive read, Dynapack reads a lot lower than a Dynojet, and wouldnt be far off a DynoDynamics or Mustang.

Dynojet reads the highest of them all.

I must ask the guy what actually happens when the user pre-set dyno rpm limit is reached. I wonder does it brick wall the rpm so the engine cant go past it. He kept lowering this, and I kept telling him to raise it lol.
As on a few runs, it did hit 7000rpm ok...although I know in the car it didnt feel too nice, which is why he kept wanting to lower it..

 

Well that why dynos are tuning aids and not good for racing because I heard different One of the local import shops uses one..

I have no idea what changing the upper rpm limit does on that dyno, just changes the scale on the graph I imagine. Trying to stop an engine through the axle in high gear wouldnt be a good idea

 

The numbers arent a concern anyway...the problems are lol. As long as I can trap 150+ this year...I'll be happy enough.

Ive been to a dyno now, twice in 2 years. So it isnt a big deal.

 

I know, just sayin

 

that was my first thought reading the description.

 

what did you a/f drop to with the meth, too far and it won't fire

 

AFR's went nuts with the 50/50, due to all the missfires.. So it was impossible to tell. I tried pulling fuel, and adding it, nothing would get rid of the missfires so I gave up trying. I didnt want to risk pulling too much fuel when we couldnt get an idea of AFR's

But before when Ive been using 100% meth, I could still run ok into the 9.x AFR's without any missfires. It would just feel flat when that rich.


Ive done a compression test today ( no leakdown tester )

Car wouldnt start to let me take it outside to drain water. Well it did...just about. Wouldnt start to drive back in though.

I removed plugs, they were obviously wet from fuel, and black. Once dry...just black and sooty. No real signs of oil. But as I say, there is some 250miles since the dyno.

Compression test wasnt bad. 1357 were all virtually identical at 11bar - circa 161psi
6 and 8 were likewise.

2 was closer to 9.9bar, 145psi and 4 was 10.1 bar 148psi. So not bad, but something defo up with those 2 cylinders..

One odd thing. Some of my inlet ports have dirt in them. Almost like a light grit. Not loads, but there shouldnt be any !. I always run an air filter, all boost pipes are spotless, TB is spotless, and even intake manifold looks to be spotless.
I can only assume its coming from the fuel system/injectors.

I only run 1 x 100mic stainless filter pre-pumps ( fuel tank only has one 5/8" outlet ) I do not have a filter after the pumps...never have done. Although its been a while since I changed the pre-filter.

The inlet mouth to the blower has a very light smear of oil on it too.....it seems to do this when spun hard. No idea if its coming from the blower itself, or the air filter. But the compressor wheel seems dry. In the 500 or so easy miles I did, the mouth remained spotless and dry.