Nytro boost level question

[slymax]

Does anyone know how much boost the Nytro can run with stock compression. I am considering running my Nytro with the stock motor (no shim) and 100LL. I ran as high as 17-18lbs last year on straight 100LL with a headshim. I understand I can use meth will eliminate deto but there is only so much room for a tank and I would like to be able to use 40-50 litres of fuel. I don't plan on changing cam timing unless I have to and my setup doesn't allow for ignition timing changes.

 

[Need for Speed 2]

You are playing Rusian rulet with your nytro no shim no cam timing and pump gas recipe for a tow job, atleast due cam timing, 6-8 would be the limit 8 is pushing it, maybe Turbo Jamie will chime in I think he has more knowledge on the stock compression no cam change on the nytro.

 

[Skydog]

On 100LL man i would say 12 psi all day! Just dont heat soak it! Back to back pulls----- long pulls ect....

Skydog

 

[mulot30th]

91 pump gaz 6 psi, 100ll, 10 psi.

 

[slymax]

Sounds not too bad. I was thinking in the 10-12 range with stock compression and timing and just run straight 100LL. We never ride below 2000' and most riding is 5-7000'. I am thinking it will be a lot more responsive than with the headshim and then add some meth for higher boost levels.

 

[yamiboost]

no worries 12psi on straight but mpi says not to use it for some reason.

 

[slymax]

Probably because they sell race fuel. I always bought my av from the local bulk station, since he became a race fuel dealer he doesn't keep av anymore.

 

[TurboJamie]

On 100LL man i would say 12 psi all day! Just dont heat soak it! Back to back pulls----- long pulls ect....

Skydog

Nope mine detonated with 100ll at 9 psi no pulls longer then 1/4 mile. Detonated 1 piston and kicked the head gasket. I always tune on 100ll until I get my fuel #'s sorted out. Better safe then sorry plus we have 200 gallons in our backyard for helicopter

 

[Need for Speed 2]

There guys I was hoping Jamie would give facts on this. The Nytro is a different animal just because it works on the 4 cyls does not mean its working for the Nytro, from the center of the piston to the cylinder wall the distance determines heat disipation rates, larger the bore theharder to extract the heat from the piston dome or center, There is way better tech guys than me on here but this is one of the many reasons this is a different beast.

 

[TurboJamie]

Larger piston or bore will always lend itself to detonation easier then a smaller bore. Alot bigger area for the fuel to burn. Cylinder scavanging is different etc. The nytro cannot survive over 6 psi of boost on pump gas, without lower compression and or cam timing changes.

I guess with timing yanked with an RB3 you would be able to get her up a lil higher.

 

[Srxspec]

The nytro cannot survive over 6 psi of boost on pump gas, without lower compression and or cam timing changes.

I will have to disagree with this. We ran all last season at 8 lbs of boost with no problems on our turbo kit. 11.5:1 a/f ratio with no timing taken out on top end at that boost level. We also did 18 dyno runs at Dynotech wide open for 10 seconds at a time with 180 degree water temps with ZERO problems. Now if you are too lean you will detonate over 6 psi at sea level. If you have the proper fuel pump, fuel pressure, and fuel mapping you can run problem free.

Great conversation here. Above sea level is also a way different game!

 

[Need for Speed 2]

A little caution and careful tuning may be the best advice, You are right on the money Allan I think afs are more critical on the 3 cyls than the old 4s

 

[wantboost]

will you see detonation on you afr gauge meaning will the readings be high or can a motor still detonate at say 12.1

 

[Skydog]

You can not see Dento on a AFR gauge. Yes a motor can Dento at any AFR.

Skydog

 

[slymax]

What AFR should I be tuning for? 11.5, 12.5 or 13.5 ? I am just gonna run 100LL straight with stock comp and cam timing. Will meth/water injection mess up the readings at all at higher boost?