Nurburgringer

Put her back on Eurocharged's dyno yesterday.

Right on the money: 50hp gained at the wheels.

Baseline curve was almost identical to the one last time she was dyno'd in May, right after Kleeman headers and EC ECU tune.

Wheel hp stock:300
Wheel hp headers/tune: 325
Wheel hp 50 shot N2O: 375

Assuming 20% drivetrain loss (362hp @ crank, published) that works out to ~450 crank hp with 50 shot of nitrous.

She feels, sounds and goes great.
Installed a fuel pressure gauge on the rail outlet going to the NEX solonoids, and it stayed firmly above 55psi the entire run.

Can't wait to go back to the 1/4 strip next month when it's a little cooler and see how much faster than previous of 13.55 sec @ 103mph she does.

Latest dyno vid, street testing and 1/4 mile racing coming soon:
https://www.youtube.com/user/kedelbach/search?query=CLK

buffyclk500

Are you going to go bigger then a 50shot

Nurburgringer

Thinking about it.

GatorMB

Remember the M113 piston is coated not forged.
Nitrous is incredibly hard on reciprocating parts and most well prepped nitrous engines have forged pistons.
The coated aluminum pistons stock M113 are the strongest available without re sleeving the engine.
The engine gets noisy and track only after the expense and its not cheap.
I bet if the engine condition is good the pistons could take up to 150 HP shot for brief period.
Consider meth cooling when going for broke.

All Fun, Gator

ItalianJoe1

Meth won't matter while on spray.

I'd advise a switch to E85 if you run a 150 shot but it will take it just fine either way.

A 50 shot is nothing to an engine this size. I sprayed 125 through my 350z with nothing done except one step colder plugs and a little timing backed out. It ran perfect for years.

FWIW, if you're gaining 50whp, that's about 65 crank, so a little bigger than a 50 shot. What numerical size jets do you have in there? 37/22 was the standard 50 shot recipe.

Nurburgringer

Good eye.
I'm going by NEX's jetting charts, the one for 55psi fuel pressure.
Started out with the jets for "50hp": #35 N2O and #19 Gas.

Ran through ~1/4 of the bottle, and wanted to go a little higher so put in the next larger nozzles on each which is #37 and #23.

The recommended jets for 75hp @ 55psi fuel pressure are #41/#23, so as expected the AF measured during the dyno runs was a little rich (see below).
One mystery is why the red line (AF during Nitrous run) is richer than the no-N2O run below 3500rpm. There was no N2O/gas injection until then so the AF should have been the same as the blue line.
Any ideas? Maybe the N2O solenoid is leaking a little?

I'm probably going to put in the #41 N2O jet, which will lean out the AF under boost and should further increase whp by 10-15hp.
My main concern is going too lean.
What's your opinion, seeing the AF curve with the #37/#23 nozzles?

I don't really want to go more than 75hp. Both because it's got stock timing/plugs and also because much more than what I'm running now will probably spin the tires in 1st when I kick it in at ~4000rpms.

ItalianJoe1

Not sure why the A/F is so high in the beginning, or why it changes from run to run. Might be dyno setup issues, the hose too long to the a/f sniffer and it was contaminated, etc. The running a/f on motor looks correct, high 12s. The a/f on bottle goes too low, i'd shoot for 11.5-11.8. It seems to come down smoothly once you hit the nitrous so I think it's all working fine, just bump the nitrous nozzle a size bigger or bring the fuel down if you don't wanna increase the hit size.

On my Z the car was very rich for a 100 shot (two nozzles, each 37/22, base pressure 58psi). I ended up going to a 40/22, rather than pulling fuel, which put me closer to 130hp but it ran very well.

Nurburgringer

The next larger size N2O nozzle I have is a 41, so a significant bump up from 37. Not really keen on paying $150 again for another set of dyno runs, do you think that may push the AF higher than 12?

I'm not going to run N2O all that often so if it's close to being too lean at least it won't be running that way for very long, like a SC'd car would be. But still from what I've read being a bit too rich is better than a bit too lean so would rather stay on the safe side than try to get another 5 or 10hp out of it.

thanks much for the input. This is my first foray into the Nitrous world. So far it's very fun

ItalianJoe1

You can buy jets in any size for just a couple bucks.

I agree on not wanting to run it lean, especially since you aren't tuning or changing plugs or anything else for nitrous. Excessively rich can still cause problems though, if the whole mixture doesn't burn because there's not enough air, you can have fire coming out the exhaust valve and burn valves and melt things. Not at an 11:1 though, you should be fine just where you are.

I'd be totally guessing on what change the sizing would give you, as I haven't played with that specific kit or on that specific engine.

Nurburgringer

Single jets are ~$14 from NEX (if I wanted to get a 39 i.e. between the 37 and 41 that came with my kit), but will probably leave it as is.

Eurocharged emailed me the curves, which are interesting.

The Blue (stock) and red (Kleemann headers&ECU tune) lines are from the first tests in May, and the green line is with the ~60hp shot of N2O last week.

The red and green lines should be the same until N20 comes in ~3500rpm. It was ~10F hotter for the latest test, but I would have thought the machine corrected for ambient temp/humidity.
I asked if their Dynojet doesn't correct use a correction factor (my buddy's Mustang Dyno results for his Camaro states an "SAE J1995 correction factor), but haven't received an answer yet.
Maybe it's within typical measurement tolerances between runs 2 months apart.

Anyway, I'm happy with the car's behavior with or without boost, so next thing to do is put her on the strip and see how much quicker she goes.

On Monday night I emptied the ~1/2 full bottle into my garage, installed a pressure gauge (with blue loctite, as recommended by NEX) and picking up the full bottle today.

Nurburgringer

Finally got her back on the 1/4 mile strip last weekend, and with the 60ish hp NOS shot saw a nice ET improvement: 13.10 sec @ 107mph (vs 13.55 sec @103mph without juice).

Was hoping to beat my friend in his 2017 Camaro SS, but he not only got the jump (0.15 vs 0.33 reaction time) but a quicker ET: 12.99 and much faster trap speed 114mph.
Good race nonetheless!

His tires were totally shot which allowed me to take off better, but ~250lbs less weight and probably a little more power won the day for him.