Upgrade options- 1800 S/C

Discussions relating to Turbochargers, Superchargers, Induction, Engine Mods, Exhaust Mods, and other items specifically to make your MX5 or Roadster put out more power.

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Timmo
I count 5-s in my sleep
I count 5-s in my sleep
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Upgrade options- 1800 S/C

Post by Timmo » Tue Oct 04, 2016 8:17 pm

Hi guys, It'd be great to get your input
Currently I have a NA, originally a NA6 but has a 1800 engine, early 'Sebring' M45 supercharger and torsen rear. Big intercooler and oil cooler. So, its got a lot of hardware to support decent power but the supercharger is only putting out 5psi...at a guess 170hp.
These original kits use a pretty crude fuel pressure regulator and a timing retard box. The car gets pretty horrible fuel consumption- it has a AFR (narrow band) gauge which pretty much always sites rich.

So, options as I see them:
Megasquirt- Hopefully find some more power AND reduce fuel consumption.
Possibly an upgrade to the existing m45 with a newer one (i.e. Mini)- Does anyone know if the basic casting and snout lengths are the same? (i.e. could I mount a newer M45 using the existing mounts, pipes etc)
???
Ideas?
Ex: 1991 BRG NA6, 1998 White RS, 1997 Wine Merlot M Edition

siren676
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Post by siren676 » Wed Oct 05, 2016 5:48 pm

Chuck a real ecu on it and get rid of the crude engine management, a proper tune will do wonders. I'd recommend getting a link ecu for easier access to tuners that will touch them
1990 NA6C MX5

Timmo
I count 5-s in my sleep
I count 5-s in my sleep
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Joined: Mon Sep 07, 2009 1:08 pm
Location: Takanini

Post by Timmo » Wed Oct 12, 2016 1:09 pm

Yeah I'm definitely leaning towards engine management (i.e. getting what I have running better).

Jared- I have a question about the trigger wheel that you use on your MS installs. Where does it actually fit? I have a crank pulley overlay which drives the supercharger, would that interfere?
Ex: 1991 BRG NA6, 1998 White RS, 1997 Wine Merlot M Edition

zorruno
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Post by zorruno » Wed Oct 12, 2016 2:21 pm

Hi Timmo, similar setup to my 94 (although it is sitting in a garage unloved!).

It is all do-able... but if you don't watch cost you'll end up spending enough to start again with a new setup anyway. Most of my gear was second hand/gifted/traded otherwise I'd have done something different.

I have a greddy blue piggyback ECU, but go with a replacement Link if you can. Haven't had any experience with the Megasquirt.

Options possible
- Spin the supercharger faster. You can make a new pulley/belt setup to do this. Needs much more precise engine management (and will likely need intake cooling)
- Intercooler. If you have something already, you might be fine with more pressure. I was given a water/air intercooler setup for mine but I never put it in. Previous supercharger owner put it together... said likely too complex for the gains.
- Water injection. Simpler but of course again needs to be managed well and it has disadvantages. If I ever spend more money on mine, I'll be doing this for interests sake.

Apparently the newer m45s from the Mini etc are a bit of work as replacements because a) mountings are different and b) they don't have the built in bypass valve for idle etc... but people have fabricated their own. It was a while since I looked, so there may be off the shelf options now.

hth

cheers
(z)

Teamjelly
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Post by Teamjelly » Wed Oct 12, 2016 10:19 pm

Hi Timmo

As for replacement triggerwheels - we only fit them on the NB1600 and NB1800 engines
You just remove the old low resolution 4 tooth wheel and fit our 36-1 triggerwheel, it's a bolt on fit as it's exactly the same as the original version just with more teeth
But............ it's not needed on any of the NA setups
We just use the existing Cam angle Sensor and all other original sensors
We've done a couple of M45 setups using the Mini R54 blower - which is just a M45 that's a bit more sophisticated
I'm actually fitting one at the moment to my own MX5 Based Kitcar.
They work really well and on a good tune with around 9psi and Water/Meth injection (or intercooling) then a healthy 190hp at the wheels is achievable - with excellent low to mid--range torque.
As for an ECU - Any half decent tuner will be able to tune it - the software is VERY userfriendly and straightforward - with even first timers able to get good results with a wideband Sensor connected - The AUTOTUNE function works really well too -
Of course we are more than happy to do it - and you'd be guaranteed good results and a well running engine
We can also manufacture pulleys for your existing M45 in order to run more boost - as 5psi isn't even scratching the potential of the engine and supercharger
Sticking feathers up your butt does not make you a chicken

Timmo
I count 5-s in my sleep
I count 5-s in my sleep
Posts: 393
Joined: Mon Sep 07, 2009 1:08 pm
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Post by Timmo » Sat Oct 15, 2016 11:44 am

Thanks guys,
Yep there's already a massive intercooler so its set up to handle a heap more boost than it has. I'm actually scratching my head a bit as to why it doesn't generate more than 5psi as it is running the larger crank pulley (which should bump it up to ~7psi). Would pressure drop through the intercooler have an effect or, barring actual boost leaks, could the lobes just be so worn that they aren't generating boost?

I need to do some research on the nose pulley- There are conflicting reports that say they cant be made smaller due to the design or the earlier 'cone' type overlapping the nose casting, but looking at mine (which is a cone), there doesn't appear to be any overlap...

Would I need larger injectors than the stock tans?
Ex: 1991 BRG NA6, 1998 White RS, 1997 Wine Merlot M Edition

Teamjelly
Need, more, 5-ing, time....
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Post by Teamjelly » Sat Oct 15, 2016 11:49 am

I'd say the stock injectors are well and truly maxed out even on 5psi
A smaller pulley is easy to do and will crank up the boost
Around 10-12psi will be fine with bigger injectors and a good tune
I have plenty of brand new 440cc Denso RX8 injectors in stock which are a bolt on upgrade
Sticking feathers up your butt does not make you a chicken

Timmo
I count 5-s in my sleep
I count 5-s in my sleep
Posts: 393
Joined: Mon Sep 07, 2009 1:08 pm
Location: Takanini

Post by Timmo » Tue Oct 18, 2016 8:06 am

Unfortunately the smaller pulley is off the cards due to the design of the supercharger- The snout casting extends under the pulley which prevents a smaller diameter (well, you may be able to reduce it 2mm or so)....and increasing the crank pulley diameter doesn't seem to feasible either as the belt would start to interfere with another pulley.
I'm investigating other S/C options as the S/C is another limiting factor.

I'll flick you an email :)
Ex: 1991 BRG NA6, 1998 White RS, 1997 Wine Merlot M Edition

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