Mi16 Nitrous Cams?

[hatemgti 4]

what cams should i get for Mi16 with nitrous ?

anyone recommend any profile or lift?

[base-1 17]

What do you use the car for? Unless it's a drag car then nitrous is a nice addition, but shouldn't really dictate the spec of the rest of the engine. You should do that to how you want it and then add nitrous afterwards - in my opinion of course - because you use it so little

[hatemgti 4]

yes i use the car for drag and i need to gain more power without increaseing the shot of the nitrous.

[base-1 17]

Only drag? Cams with profiles suitable for forced induction are what you need, as essentially that is the effect nitrous has on an engine. It will work with any profile though.

[hatemgti 4]

would you think stage II peterT cam would work ok with my engine ? and do changing the exhaust cam in my case would give me any gains?

[petert 556]

Your choice of inlet depends on your primary use for the engine. ie do you want a daily driver that can double for an occasional drag. Or do you want a drag car that is street drivable occasionally? The Stage II inlet can do either really, providing you have enough CR.

 

The exhaust cam choice then depends on how much nitrous you're going to give it. It's the same as other forced induction applications. I normally recommend using a std. exhaust cam for street cars (with Stage II inlet) or Stage I on the exhaust for track cars. I would run the Stage I with wider lobe separation (ie decrease exhaust lift @TDC) and/or run the Stage II on the exhaust as well.

 

eg

 

Stage II inlet & Stage I exhaust

or

Stage II inlet & Stage II exhaust

[Mattsav 1]

Nitrous requires similar profiles to a supercharged engine.

 

To get the best out of turbocharged engines you require a different exhaust profile and timing (for 4&5 valve per cylinder engines anyway).

[hatemgti 4]

my engine is standard internals(alloy block) with +80 hp nitrous, what performance i would reach with either stage II inlet and (stage I exhaust or stage II exhaust).

[pip470 61]

Why do you not want to increase the amount of nitrous?

[hatemgti 4]

because i am not sure how much its safe for nitrous?what is the max. Jet nos could be used for single and DP with standard Mi16?

[petert 556]

Here's a thread about an 8V on NOS which made 183hp at the wheels, with a 75hp shot.

 

http://www.aussiefrogs.com/forum/showthread.php?t=8061

 

http://www.aussiefrogs.com/forum/attachmen...tachmentid=1587

 

You should be able to pull 220-240hp at the wheels with a 16V. I'm sorry if I didn't explain it very well, but Mi16 heads have very efficient exhaust ports. So with a N/A engine you don't need a lot of exhaust cam timing. Thus why I suggested a std cam for them. A 16V on NOS however, will need more exhaust timing than normal. Big V8's, with inefficient exhaust ports, have to run a lot more timing on the exhaust when running NOS.

Edited February 24, 2009 by petert

[hatemgti 4]

you mean like making exhaust cam timing 111 degree?

[petert 556]

No, more like 120 degree.

[hatemgti 4]

so i need cam pulley or an offset key?

[pip470 61]

because i am not sure how much its safe for nitrous?what is the max. Jet nos could be used for single and DP with standard Mi16?

 

 

It was kind of a loaded question really, sorry. But, the reason I asked is because the changes you intend on making are for what? To make more power? The cam timing will increase the effinciancy of a given amount of nitrous. So your using a 75 hp jet, you may only see a gain of 20-30 hp gain on a normally asperated engine, (assuming its a wizzard of nos kit). With the more focused engine with the revised cam timing you may see a bigger gain from the same nitrous hit. (75hp) Either way the power has increased. Theres no differance in making more power with a bigger jet or a more efficiant setup. Consumption of nitrous will be higher with a less efficiant setup though which could be a reason to do it but as always on the other side of the coin, finding the limit of a standard engine is a lot less costly than finding the limit of an engine you have spent money changing the cams on. One of the plus sides to nitrous I think is that to increase the power, you just have to change the jets (around £10). You will reach an upper limit on nitrous but on a standard engine I dont think you will get anywhere near the capability of nitrous as the engine will let go first.

 

What is the safe limit of an engine? Well surely its the point under the time when somthing is about to break. All I'm saying is even after you have made the cam changes, you might have just passed the safe limit of the engine, but you might not of. If you were building a dedicated nitrous engine with a steel bottom end then I think tuning the cams to make the most of a given amount of nitrous would be bennificial. As its standard I would maybe just look at other things on the car to make you go faster like, less weight, lsd, better tyres ect ect. If you want to push you're engine further, Then just change the jets. It will be a lot cheaper. Good luck with it, let us know what you decide.

 

Phill

[hatemgti 4]

i think i would go for the cam timing first now i am using #2,#2 pulleys i don't know how to make the exhaust cam 120 degree ? any suggestions ?

[petert 556]

I could sell you a 4 deg. offset key, which would push the exhaust centre line around to 118 degrees. Cheap and easy to try.

[hatemgti 4]

I could sell you a 4 deg. offset key, which would push the exhaust centre line around to 118 degrees. Cheap and easy to try.

how much it costs and do using #3 pulley in the inlet in my case of nitrous will be an advantage or will make the engine knock ( i am using octane 95)? also i am using motronic 1.3 with knock sensor?

Edited February 26, 2009 by hatemgti

[petert 556]

#3 will be fine.