Operation "Hamster Swap" has been initiated..

[TroyV]

It does. I'm just a little concerned with how it drops off so fast after 6k. I have old 1.6 charts that this curve crosses under between 6 and 7k.

It probably amounts to grabbing the shifter a little earlier in spots.

 

[LargeOrangeFont]

It does. I'm just a little concerned with how it drops off so fast after 6k. I have old 1.6 charts that this curve crosses under between 6 and 7k.

It probably amounts to grabbing the shifter a little earlier in spots.

That seems about par for the course. I believe the 1.8 was only supposed to give more "area under the curve" and not really much more peak power, is that right? Are the cams any different between the 2 engines? If so are you allowed to change them if the 1.6 cams are more agressive?

The low end torque gains would be more than worth the tradeoff for the increased top end falloff I would think.

EDIT: All dyno charts should cross at 5252... Are you sure the old charts do not have different scales for HP and TQ? That would explain the difference you are seeing.

 

[TroyV]

For my class, the engine has to remain stock as delivered. Also, I'm not sure the 1.6 cams are compatible. The 1.8 block is 20mm longer than the 1.6 to make space for the larger bores.

I compared these curves to every other one I could find on the web that had a 1.8 with similar mods. This one defnitely dies early by comparison. Not a big deal, I'm sure I can adapt. I may just try to run a higher flowing cat to see if the curve goes more gradual.

 

[LargeOrangeFont]

For my class, the engine has to remain stock as delivered. Also, I'm not sure the 1.6 cams are compatible. The 1.8 block is 20mm longer than the 1.6 to make space for the larger bores.

I compared these curves to every other one I could find on the web that had a 1.8 with similar mods. This one defnitely dies early by comparison. Not a big deal, I'm sure I can adapt. I may just try to run a higher flowing cat to see if the curve goes more gradual.

Gotcha.. I think I will be getting into a spec Miata in another couple years here so I should probably start reviewing the rules. I gained so much more speed driving my 150hp rotary powered RX7 than I did in my Cobra... and it was more fun.

 

[TroyV]

There is a lot to be said for having to wring every last bit of speed from a low power car. It means you need to take turns at speeds which would be absolutely terrifying in a Mustang....and that is just put down a respectable lap time.

 

[gcassidy]

Troy, having just gotten mine back from a dyno tune last week after a month of work, I still didn't break over the 300 mark myself. Looking at power/weight, I think your's is awesome. I did manage to bump up my torque by 20 at 3500. Don't you love getting excited about low end torque?

EDIT: All dyno charts should cross at 5252... Are you sure the old charts do not have different scales for HP and TQ? That would explain the difference you are seeing.

Ashley, why is that? I looked at my before and after sheets, and sure enough, they do. Is it a reason an engineering-challanged person like me would understand?

 

[LargeOrangeFont]

Greg,

The short answer is because horsepower is a function of torque.

The actual equation to find HP is

HP = ((2Pi)(TQ in ft lbs)(RPM)/33000)

We know that
33000/2Pi = 5252

To condense that down

HP = ((TQ X RPM)/5252)

 

[gcassidy]

Thanks. I get it a little bit. :dw:
But I'm gonna do some reading till I understand it better. :idea:

 

[LargeOrangeFont]

Thanks. I get it a little bit. :dw:
But I'm gonna do some reading till I understand it better. :idea:

All 5252 is, is a mathematical constant. HP is not an actual "thing" that can be measured like torque, since it is a function of torque.

 

[TroyV]

My head hurts.