Finally got around to having my '5 tested on a dyno after the mods that I have carried out, and am quite pleased with the results. For reference I used the graph on miata.net for the early 1.6, 115bhp, 98 bhp at the wheels. I now have 107 bhp at the wheels and 125 at the crank, so the seat of my pants is right.

The mods done are :-
Borla cat back,
magnex cat relplacement,
PiperX induction kit
and Magnecor wires.

Putting the timing to 14 degrees gives 2bhp extra, as we did a before and after run. So all in all, very pleased, plus she sounds sooooo much better. (12/99)

Right just got back from the dyno tests, and I'm still down on power, tested at 130/132 rear wheel BHP, with a 22k resistor it was still running weak so upped it to 33k, still weak, went and got a tank of super unleaded (pocket now weak!) but fuel ok, I'm only posting 5psi boost max at 4500 rpm.

So any more ideas accepted (I wonder how many people fit without dynoing....) Oh and the idle compensator was delivered but as there were no definite instructions in the instructions the garage rang Moss technical London who said.....'thats just for the USA market throw it away.....' (1/00)

Oh and the idle compensator was delivered but as there were no definite instructions in the instructions the garage rang Moss technical London who said.....'thats just for the USA market throw it away.....'

What was delivered? Boost switch, relay, etc. or just a resistor? And I wonder why you were so lean even with a meaty resistor?

So any more ideas accepted (I wonder how many people fit without dynoing....)

Guess I ought to dyno mine at some point. I'd like to get my intake stuff sorted first, though. (1/00)

1.8 Sebring 149 rwhp 130 ftlbs (MSD) ... is a figure I have from US mass dyno session but that is a 1.8 and it is on a dynojet ...

so .. 1.6 would be ...132 rwhp (1.8/1.6 x 149)

So 132 rwhp is right for a 1.6 Sebring .. but if you have a 1.8.... then ...

dynojets are good at putting out 'large' hp numbers ... I was only 210 rwhp on a Sun dyno in UK where most of US listers with the same kit are 235 rwhp on dynojets.

Some numbers;
1.6 BEGI 1 140 rwhp ? ftlbs (6 psi, stock, quote from DA)
1.6 BEGI 1 161 rwhp 146 ftlbs (7psi, no I/C, FM exhaust, ER plugs)
1.8 Sebring 149 rwhp 130 ftlbs (MSD)
1.6 Aerodyne 186 rwhp 165 ftlbs (9psi, FM exhaust, FM ECU, no cat, BEGI racer I/C
1.8 FM2 238 rwhp 221 ftlbs (14,5 psi, not redlined)
1.8 FM2 260rwhp at 6210 rpm and 240 ft/lb at 4000 with 15 psi and straight exhaust pipe 49 hp at 2000, 105 at 3000, 180 at 4000 125 ft/lb at 2000, 185 at 3000 and 240.5 at 4000.

so the other choice is to try another dyno or ask for numbers that are similar on stock cars on your dyno ... my comparison on my dyno was a 4.0l TVR that should have 240 fwhp that only gave out 160 rwhp .. I suspect the dyno reads low in my case .. this was borne out on the track where similar power/weight vehicles were in the 220 bhp/tonne range .. which is about right. (1/00)

Right just got back from the dyno tests, and I'm still down on power, tested at 130/132 rear wheel BHP, with a 22k resistor it was still running weak so upped it to 33k, still weak, went and got a tank of super unleaded (pocket now weak!) but fuel ok, I'm only posting 5psi boost max at 4500 rpm.

Did you back off your timing? Was the J&S cutting in on the dyno? Feedback is that the 14 degrees we set is aggresive even for this cold weather and a bit of J&S is to be expected. The fact that SU helped suggests this is the case. Any J&S activity shows your timing is being retarded and setting some "static" retard should boost peak hp even if you loose at the bottom end. It all depends on whether you're more interested in dyno figure or driveability, but I fully understand that at the moment you just want to dyno to check everything is 100%. (1/00)

Normal figures for a 1.8 are around 145 RWHP. IIRC these values are reached when besides the SC not only a MSD or J&S is installed, but also free flow exhaust parts. But the RWHP values that are reported are not always the rule. When I had the SC, I also had the J&S, a JR header, a JR exhaust and a one way valve installed. I was making: 125 RWHP. On the same dyno a 1.8 was making 140 RWHP.

The resistor only makes sure you're not running lean. It doesn't up boost. In fact leaner means more HP. But the fact that a lean mixture will lead to detonation and therefor destroy the engine makes you want to go slightly richer. It's allways a balance between mixture and safety.

Timing and sensivity of the J&S play a big part in the perfromance too. The J&S may be taking out to much timing.

IIRC the one way valve in the ICS line also works in the 1.8. But the design might have changed over the years, so I am not sure.

Belt slippage is also a factor.

One final hint. Don't value the performance by the dyno figures only. Value it by the grin factor it produces. You can't show off with that down the pub, but it makes you more happier when you drive the car. That's the reason I have never dyno-ed the MX-5 or the Impreza turbo. I get a great grin factor and I strongly believe that both the Impreza and the MX-5 produce 240 HP at the crank. If not, the feel fast anyway to scare myself silly. (1/00)