Curious -- anyone around here running a 150 shot with only pulled timing, but no tune? How'd it go?

 

It goes...


































BOOM

 

lol, has anyone actually tried it, who did go boom? I mean, is a tune for a 150 absolutely required, even with a lot of timing pull? I understand the current sentiment that it needs to be done, but I'm just looking for some actual evidence.

 

A long time ago when the Z33 first came out I believe a group of guys, or a shop, sprayed a 175 shot down the strip. Needless to say, the block couldn't hold and the car scattered pieces of its block down the quarter mile.

Anyway, isn't pulling timing part of the tuning process? If you are going as far as pulling some timing for such a big shot, why not spend a extra to do it properly? Why skimp out on the tune, which is the extremely crucial to the process especially at higher power levels?

If you want, you can always be one of the few that sprayed a true 150 whp shot into your stock block... and blew the motor to smithereens.

 

I knew a local guy who had a Z with a 150 shot on an otherwise stock motor, but it was tuned. I can't see running that much spray untuned, that's just asking for problems.

 

Go with 150 shot. Never know. You might make 13.8 seconds.

 

OH SNAP!

 

So I made like 440Tq with a 100 shot...so a 150 would be like what....500+??


I had a dyno done with a 125 shot@1000psi and only made about 9 more whp BUT made another 30Ftlbs or torque. It becomes diminishing returns with more unwanted motor busting torque.

I quickly put my 100 jets back in.

 

 

 

nitrous burns faster and provides more torque at a slower rpm than it does at a higher rpm. Dyno graphs show this clearly.

Also, the "shot" is a hp rating, so going up from 100 to 125 techincally should be about 25 hp which doesn't really mean you have to get a huge jump in torque. You might down low, but total torque will probably not increase a lot.

anyways, like someone said, if you are reprogramming the timing then why not just tune the afr so the car runs good? I know just pulling a few degrees of timing isn't going to be enough.

 

Not very clear here, and kinda wrong.

Jet size controls the flow of nitrous, like bigger or smaller injectors, but they are full-open or full close, they can't pulse (progressive controllers are another story...).

A given jet size flows the same amount of nitrous at all times, assuming bottle pressure is constant. This means, a .046 jet (100 shot rating) is supplying the same amount of nitrous every second at whatever rpm your engine is turning. You have fewer rotations at low rpms, but the same nitrous flow. This results in more nitrous per cyl firing cycle at slower engine speeds, which is why you see more torque down low than up high. Nitrous, in effect, "tapers off" as the rpms climb, you are getting less nitrous per cyl per cycle, so you get less gain in power, but engine output climbs naturally with rpms so it is not a big deal. It also works to prevent extremely high cyl chamber temps and EGT, as the chamber gets hotter, if you kept feeding it more and more nitrous, well, as production engine would not be happy with that for long.

The "shot" rating means nothing, you will see the gain in torque down low of course, and it will taper off as rpms climb, but in general, a 125 vs a 100 shot should gain 15-20hp at the wheels (drivetrain losses and so on, depends greatly on the platform, N/A vs. FI, etc...).

The key to all if it is to look for a happy medium. We know the stock block is not happy at 450wtq, so that is not a good idea. Two methods of keeping that in check would involve more gradual onset of the nitrous (progressive controller, two stages), or timing control (softer timing settings around the activation point, or higher octane fuel to help slow the burn down a little bit). You can also tune for a slightly richer A/F at that point as well, to soften the blow to the piston/cyl, but thats not the ideal thing to do.

 

Well, I knew there was a better answer to the rise in torque at low rpm and the taper. I stay away from that stuff (not a big market in my town anyways) so I don't know the specifics. Thanks for clearing it up.

 

i know of a g35 with a 150, one step colder plugs, and meth injection. nothing has happened yet

 

nitrous AND a meth injection and he didn't tune it? i call bs on that.

 

^here is a link for you to educate yourself a little bit before telling me im bs'ing, if you need more, let me know

https://my350z.com/forum/forced-indu...injection.html

 

you should read better. first post he states he is using an EMS which is what people use to tune.

so he HAS tuned the car. maybe not dyno tuning but he's not running a stock ecu. he also said he has a meth controller that retards timing.

so now go find a car that is stock ecu with NO TUNE with 150 shot and come back.

and again later he states that he does his own TUNING.....

 

look im not trying to start an arguement here, but the whole point of why i posted that is to show that meth injection helps mitigate the bad effect of nitrous by cooling the intake and effectively raising the octane level. that thread was not exactly the same as this situation, but the same principle applies. you implied with your post that it would worsen the effects of nitrous.

all that aside, i still stand by my post, 150wet shot, 1 step colder plugs, meth injection, and stock tune. believe me or not, i dont care, i have no reason to make it up

edit: actually im prettys sure it was a 350z, not a g35, but thats irrelevant

 

how is it a stock tune on an aftermarket ems? explain that

 

thoretically, if you get the proper sized fuel nozzle, you wont need to touch the AFR. A simple Cipher cable to reduce the timing by 2* and you could be just fine.

Block safety would mainly depend then on how early you start to spray. Like others have said at 3000, the car stock parts wont like 400+ ft-lbs.