JUST HAD MY MK1 1.8 EUNOS ROADSTER DYNO TESTED...

Technical Area Engine, Transmission, Exhaust etc
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 …With some interesting results!

I’ve been saying for a while now the car doesn’t feel as powerful since i had a replacement engine put in.

I’ve just had the car put on a rolling road by Ajec Racing near Cheltenham.<o:p></o:p>

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To my horror we found she was putting out only 103bhp compared to the 131bhp that she’s supposed to!! As well as that, she was only producing 95 lb/ft of peak torque against 114lb/ft peak torque! <o:p></o:p>

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They adjusted the timing (the car has previously been set to 14 degrees), not sure if it was up or down, but i assume it must be back towards the 10 mark. This increased power and torque to 117bhp and 106 lb/ft which, while still not great, does feel an awful lot better. <o:p></o:p>

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The difference under 3,000 rpm is like night and day as at 2500rpm there was a difference of 27 lb/ft in the torque figures!<o:p></o:p>

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Crazy that there was that much difference after a 30 minute fettle and a few runs on the rolling road, it cost me £99 all told, but i’m glad I went. <o:p></o:p>

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Even if, like me, you don’t fully understand the science behind the figures a 13.6% increase in peak power and a 36% increase in torque at 2,500 rpm is huge!

The question is: What else can be done easily (without modifying) to coax some more of the horses back to the stable?

I have a K&N Filter, and decat pipe and obviously the next upgrades could be manifold and cat back sysetm, but i’m convinced the engine should be putting out more as it is now! It’s apparently covered less than 33,000 miles! I’m a quarter through a tank of V Power with a can of BG44k added to try and clean up the engine - worth a try i thought - any other suggestions? I was thinking, diagnostocs and compression tests…

I will try and upload the dynograph later for reference, the torque curve is now nice and smooth, we just need to find another 8lb and 14Bhp…

<o:p> They also commented that the car was running very rich, how can this be addressed and what effect might that have on performance?</o:p>

 

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 Wasnt the 131 at the flywheel and your readings at the wheels though?

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 No, the 117bhp was at the flywheel, i did check, but my hopes were dashed!

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I’m no dyno rolling road expert, but I’d say now you’ve had your 5 tweaked and its producing 117BHP compared to the factory quoted 131BHP thats not too bad for what is getting on for an 18yr old car.

Look at it another way, its only just over 10% loss over all those years, hopefully someone might be able to suggest what to do to liberate a few more ponies for you.

 

*Sorry just re-read and you say your “new” engine has supposedly only done 33k - still thing to bear in mind maybe is how old is the actual engine though?

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 I know what you mean though, i’m just aksing more in hope than anticipation! :slight_smile:

Couldn’t tell you much about the engine except http://apiengines.com/petrol.php tell me that it had less than 50,000 Km on the clock when i bought it. According to the garage that put it in, the manifold had an egr valve (so i don’t think it came from Japan) and the throttle body looked like it had come off an automatic. I gave Mazda UK the engine number and they contacted Mazda Japan, but they couldn’t tell me anything about the engine. :frowning:

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 Get a big turbo on it! that will sort the power out.

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That doesn’t sound right, a sub 50k engine should still put out close to OEM spec.

Even allowing 10% inaccuracy in the dyno, you can’t lose 25bhp from a car that’s just been sitting around. 

It could be gummed up with old oil, try flushing.

 

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 Even my 140k miler 1.6 was bang on when it was tested.

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Well to me, the things to bare in mind are …

Obviously the timing correction has accounted for a fair amount of the difference, it may simply be that the new engine just doesn’t perform as well.

Then the age old argument of the validity of the rolling road reports - where both runs done on the same machine, where they both in similar climates and has the machine been re-calibrated in the time between the runs. Personally, I don’t tend to pay a great deal of attention to rolling road reports anymore - more often than not I regard them as a ‘guide’ to a cars performance these days.

There is a possibility that the engine may be down on power for another reason yet to be identified.

 

Word of caution though - keep a close eye on the car if you’re using added “flushing” agents - i’ve seen useable engines destroyed courtesy of that stuff  Sad

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As an afterthought, you’re report above shows the run done in 3rd gear - were both of the rolling road reports done

in the same gear? - If they weren’t then you may just be seeing transmission losses?

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Wouldn’t be suprised if the Auto was detuned. It certainly was on the 1.6

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 Apparently not, i have researched that and i guess it must be because the 1.8 is more torquey than the original 1.6

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I’m sure they were all done in the same gear They carried them out in the first place to find 103bhp, fettled with the air filter, AFM and ducting, tried again (no improvement) then adjusted the timing in real time while on the rolling road and got the 117bhp.

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Well i’m only around 10% down on the “stock” figure now, so margin for error could account for some of it.

I gave the car an italian tune up yesterday, probably wont spend another £60 getting it tested again though. Hopefully after the BG44k has well and truly run through the system it’ll help some more, but as long as it feels lively enough i’m happy. Given that the engine has only covered about 2k miles per year it may just need to loosen up a little.

I’m gonna get booked in with WIM for the geometry setup soon, i’ve got a trackday at Silverstone with MOT on the 1st of March, well excited!!! {#emotions_dlg.bigsmile}

 

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http://www.rri.se/index.php?DN=14

They have the 1.8 engine tested here and it was outputting a fair bit less than mine (109bhp and 100lb/ft), so i feel a bit less bad about it now!

http://www.rri.se/popup/performancegraphs.php?ChartsID=341

 

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Surely the Powertrain figures are exactly what you would expect. The standard engine has about 129bhp [at the flywheel] the tested car has 109 bhp at the wheels. 20 bhp lost in transmission is not a bad figure.

 

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 not sure if they’re referring to rear wheels or fly wheel

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I’ve been told that the timing for the higher Dyno test was set to 19 degrees BTDC. Is that too much? Would that impact negatively on the headline BHP figure? More importantly could the timing damage the engine!!! Why was the engine running so crap at 14 degrees!!! Should i have it set back to 10 degrees??! Sooo many questions!

I’ve also found out that the power steering has an oil leak and i will need a replacement rack. Might go to Autolink for their used exchange option. Failing that i might consider ending it all, i have spent so much money {#emotions_dlg.sad}.

ust got myself a Milltek Stainless Cat back exhaust, blissfully unaware of yet more money to be spent. I only just had the geometry set by WIM too!