Miata Mailing List: November 1996, Message #75
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   From: Brian Goodwin 

Subject: Re: Horsepower Claims: confusion.

   Date: Fri, 1 Nov 1996 17:15:34 -0500



At 03:41 PM 11/1/96 -0500, you wrote:

>It seems funny that no one can agree on how much power a modified Miata puts

>out.  I have heard that a Sebring will increase the power up to about 170hp

>on a 1.6L and that the 0-60 time decreases from the mid 9's to the mid 6's.

>But now someone is saying that only around 139 hp is available with this

>addition?  What gives?



The answer is mostly confusion.  Confusion between rearwheel numbers and

crank numbers, numbers for 1.8 rather than or instead of 1.6, etc.  We go

round and round and round on this and still there's always somebody who

misinterprets or misunderstands or thinks we were talking about a 1.8 engine

when we were in fact talking about a 1.6, etc.  



Here are the facts from my experience.  Sebrings on 1.6's seem to dyno in

the 125 to 135 range normally (yes there may be exceptions above and below

but who cares--this is range you can expect to be in).  The 170 figure is a

"at the crank" number.  Remember that you lose power getting to the wheels.

Comparing power at the wheels is a much more reliable comparison because the

conversion accountings vary wildly ( I've seem multipliers on this list

ranging from .15 to .28).



1.8 engine sebrings are dynoing significantly stronger than the 1.6 cars, as

we should expect, into the 150's on Jackson's dyno.  I dyno'd my autorotor

1.8 at Mechtech a few months back.  A friend in the local club dyno'd his

1.8 sebring on THE SAME DYNO.  In three runs I peaked at 168, 167, and 168

rearwheel horsepower (playing a bit with air/fuel ratio between runs).  My

torque also peaked at 168 ft-lbs.  The 1.8 sebring made 148 peak rearwheel

horsepower and 138 ft-lbs torque.  Similar mods on both cars including J&S

units with both cars set at 15 degrees of timing.



Brian Goodwin





>

>I have in front of me a claim that the addition of a Jackson CAI, a header

>and an exhaust sytem can produce "up to 145 hp"  That's a lot of power

>gained from just three aftermarket intake and exhaust components.

>

>Speaking of intake mods, one catalog I have says that the K&N and HKS

>systems add 6 hp, but that their own mod, which looks almost identical to

>the other two adds 7hp.    wow....  I'd better buy that one!  >>grin

>

>I've also visited a web site that contains Dynojet Dyno graphs of a stock

>Miata that was run on the dyno stock, and then run again after the addition

>of the Jackson CAI.  The hp increase was about 4-6 I recall which is

>different from the 11-15 hp increase claimed by yet another catalog that

>sells them.

>

>I realize that diffferent dynos produce different numbers, and I really

>don't care how much power my car really has.  I'd prefer to think of it in

>terms of what kind of other cars could it potentially embarass?

>

>I think a list is in order, starting with stock and working progressively

>toward heavily modified, that has the Miata, with specific engine

>modifications in one column, and the cars it could knock off  in the other

>column.  That would be much more useful. 

>

>Ok, just a though...

>

>Kurt

>TEAM Too much time on my hands

>

>

>

>

>













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