CA18DET Lean

Discuss topics related to the CA18DE and CA18DET series engines.
daveb666
Posts: 6
Joined: Fri Oct 31, 2014 1:26 am
Car: CA18DET Kit Car

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I went to RS Tuning (UK) this week to have the gizzmo setup properly. At just under a bar of boost the car was making 262bhp but a lowly 225lb/ft torque.
It also went reeeally lean between 5-6k.

I'm going to swop my fuel filter, and check the pumps to make sure they're flowing what they should be but I'm just curious if anyone has any other ideas while I'm there.

Its a h-dev chip(UK), which from my reading should run fairly rich?

Mods - unknown ca18 engine, t28, IC, cone filter, 255l p/h pump, 3" downpipe + exhaust, bcp7res plugs gapped to .75mm.

Curious to hear any other thoughts that I may have missed.

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boost_boy
Posts: 7162
Joined: Thu Nov 14, 2002 7:28 am
Car: B12 sentra w/built CA18DET, B12 sentra w/fully-built CA18DET, S13 coupe w/ CA18DET, S13 hatch w/CA18DET, 2002 maxima SE
Location: Miami, FL.
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You got 262bhp and 225lb/ft. of Tq. out of yor CA @ just under a bar of boost? Man, you got more than enough from that lowly T28. Seriously, your torque reading is pretty good considering you don't know the full condition/mods of your engine. Not bad at all in my professional opinion ;)

daveb666
Posts: 6
Joined: Fri Oct 31, 2014 1:26 am
Car: CA18DET Kit Car

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I suppose that's true :-p

Its more the lean factor I'm concerned about.

Buddyworm
Posts: 416
Joined: Tue Jan 09, 2007 2:55 pm

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Do you have a datalog of MAF voltage and/or injector pulsewidths? If you see your mixture going lean when your pulsewidths are rising that could hint at a fuel flow problem.

I'm curious why the AFR's dropped back down again towards the end of the pull. A thought I had is your head might be outflowing what the map was tuned for in the RPM where things went lean. Then the EGR reversion effect from turbine backpressure at the top end brings the AFRs back down by displacing oxygen.

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Cams
Posts: 307
Joined: Sat Jan 27, 2007 3:42 am
Car: 1993 Nissan 200sx CA18(DET) RS13
2002 Mitsubishi Airtrek JDM 4G63T (wife)
2013 Scion FR-S
2016 Infiniti QX50
Location: Panama, Central America

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Hi, are you using stock Fuel Pressure Regulator or an aftermarket one? Isn't it recommended to upgrade the FPR once a higher flowing pump is installed? Couldn't it be that its not able to hold the fuel pressure on full boost?

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Izento
Posts: 438
Joined: Fri Dec 12, 2008 12:20 pm
Car: RPS13

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I'm running lean around that area too. I just bought a AFR gauge so I'll really see if I'm lean (my assumption is from Power FC knock reading).

daveb666
Posts: 6
Joined: Fri Oct 31, 2014 1:26 am
Car: CA18DET Kit Car

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I have no logs or anything unfortunately.

The fpr isbstock, its not recommended to upgrade it on this setup. (Or certainly not a requirement).

A friend has suggested getting my injectors cleaned as they're probably at least 20 years old now. I'm also picking up a z32 fuel filter today in case that's the problem.

My ca18 is early, so has no lambda at all - I don't know if this is one of the reasons the chip can't cope with the fuelling or whether or not I have a problem.

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float_6969
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Posts: 19853
Joined: Mon Aug 26, 2002 1:55 pm
Car: CA18DET swapped 1995 Nissan 240sx (too many mods to list)
2015 SV Leaf w/QC & Bose (daily)
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First off, it's not lean, at all. Lots of that AF plot is below 12:1, which is just wasteful unless you're trying to compensate for a poorly sized intercooler. Even when it does lean out, it only leans out to 12.5:1, which is about where you should be anyway, maybe a little leaner even. I will say that the jump in AFR is odd though, but the fact that it gets rich again tells me it's in the tune somewhere.


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