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Discussion Starter #1
Hi all,
Did an engine swap a few months back into my 2006 Exige, engine built by BOE - 2ZZ w/ stage 3 cams, arias race pistons, nikasil cylinders. It is a used engine so I get that it's unknown, but according to the previous owner should have 1 season of competitive auto-x, 4 HPDE's and a couple k of street miles. Attaching the dynojet run we got of this.

Specifically want to call out the air/fuel ratio - that looks very abnormal to me... can someone who's seen BOE 400 builds confirm? Engine should be putting out 18 psi(to be confirmed) and they said they didn't find any leaks, but my shop is starting to diagnose & see what's up. I was expecting more along the lines of 320-340 whp out of this.

Apologies for the image quality - the red line is my car, the other two are baseline non-supercharged elise/exige data they had on file. Without any further data at this point, I'm suspecting either cam timing, air intake not functioning as expected, tune, or injectors. Thoughts?
71307.jpeg
 

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Yeah.... Those AFRs should be between 11 - 12.4 at WOT and 14.x at idle. You're rich, I would check air intake first. Seems like the injectors are working fine :)

What's the comment about "spew water"?
 

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Discussion Starter #3
Thanks! Would be great if it's just not getting enough air, seems like a solvable problem. Unsure on that comment - also the date of the red graph says 2017... I've asked my guy what's up with that.
 

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Also, check your fuel pressure if you are running an external pump. I set mine at my shop but when I got on the dyno the AFR was below 10. Checked the fuel pressure and it was too high. Lowered it and the AFR came back to a reasonable number and the HP came up.

Later,
Eldon
 

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It's a bit rich after 6.5k rpm but not something that's worth 100hp. I suspect there is more to it.
Are the VVL and VVT solenoids working?
What pulley size?
Reading on the boost gauge?
Have you checked for correct by-pass valve operation?
What ECU are you running?

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You may want to inspect your lift bolts and intake cam for wear and make sure you have no broken intake manifold bolts and studs.
 

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The car won't be making 18psi. Probably more like 15 but likely 14psi. Yes, it should be making around 330whp.
 

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Discussion Starter #8
Thanks everyone! Great info here that I've relayed to my shop. Will report back once they have more for me. I believe it's running the 76mm pulley, don't have a boost gauge connected(should probably fix that), running a BOE rev 400 tune(sent the ECU to BOE for the tune).

Not sure about that spew water comment, my guy mentioned the date & comment info were messed up & to ignore.
 

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Oh, I would have guessed you'd be running the 65mm pulley. With a 76mm pulley, the boost will probably be around 12psi... and might make 300+/-
 

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Discussion Starter #10
Hey everyone! Good news & bad news. Turns out it was the air filter. Running without the filter, the engine produced a solid 16 psi. I had my shop build me a new filter (surprised the BOE one was performing so poorly), and the dyno run was much better - 300 whp up to 6k rpm, but then the AFR spiked and they immediately stopped the test... this one is a little surprising. Attaching a photo of the dyno run. The blue line is my car, the red line is the 1st owner's dyno run - looks like I'm trailing him about 10 whp, but my exhaust & possibly fuel is different. His engine's producing 330 whp at 8500.

My shop did compression, leak down tests, verified there was no cam wear, checked spark plugs & injectors. By all measurements it appears to be healthy. Injectors are 750cc Bosch ones from the BOE site.

Currently suspecting the tune... thoughts?
 

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A lot of variables for running an off the shelf tune. Spike coincides with factory high cam changeover. Could be coincidence. Be interesting to know where the high cam is set to engage and how the cam phasing has been adjusted to account for the aggressive cams.
 

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Discussion Starter #12
Good point about the cutover. It's running the BOE Rev 400 tune, so I think the cutover happens much earlier than stock - though we do see AFR's start to rise at just past 6k. I'd sent in my ecu with engine details in my tune request form. Andrew from BOE says that there is no way a tune can result in the graph we're seeing here, he says it could be an injector issue... another variable here the intake. The AFR's looked just fine in the first graph with the clogged BOE intake(which I'd specified as my intake in the tune request form). I do see on BOE's site that their ITG intake requires a special tune... wondering if it could be on account of that.
 

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I can't imagine the tune would be responsible for the rapid rise of the AFRs into the stratosphere after 6250rpm. The intake didn't change proportionally at 6250 so I don't think that would be it either.

San
 

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Do you know what your injector duty cycle is and do you have a boost referenced fuel pressure regulator? You may be running out of injector if you are not boost referencing fuel pressure.
 

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When they built the new intake did they change the size of the piping for which the tune was created?
Does the A/F start to go lean at all throttle positions above 6k or just at WOT?
As others have suggested, check fuel pressure under load, check injector duty cycles and MAF voltage.
What is your fuel setup?

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Discussion Starter #16 (Edited)
Thanks for the advice everyone! I'm following up on some of these. Re: injector duty cycle, unfortunately I have no idea what it's set to. BOE did the tune so they have all the details.

Re: AFR at throttle positions other than WOT, they didn't test that on the dyno, and I don't have any gauges in the car at the moment, something I'm fixing. Need to install boost/AFR/fuel pressure gauges.

Re: my fuel system, it's the standard BOE surge tank setup. Andrew at BOE recommended I open the lid & see if there's anything going on in there as they've seen some issues with it in the past. Another tell is that I'm getting pretty strong fuel odor coming off of the surge tank. I'll be opening it up in the next few days, hopefully there'll be a smoking gun there.

Edit: Re: the air intake, the new one's hose is about an inch smaller in diameter than the BOE ITG intake that was on there before. Could very well be affecting things. Though despite the smaller hose, it seems to be much freer flowing than the BOE one.
 

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Edit: Re: the air intake, the new one's hose is about an inch smaller in diameter than the BOE ITG intake that was on there before. Could very well be affecting things. Though despite the smaller hose, it seems to be much freer flowing than the BOE one.
[/QUOTE]

They didnt resize the maf housing did they?
That is pretty critical to keep the same size as the one that comes with the kit as the maf scaling is done according to that.
Resizing that can do all sorts of things to afr's.
 

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Discussion Starter #19
Edit: Re: the air intake, the new one's hose is about an inch smaller in diameter than the BOE ITG intake that was on there before. Could very well be affecting things. Though despite the smaller hose, it seems to be much freer flowing than the BOE one.
They didnt resize the maf housing did they?
That is pretty critical to keep the same size as the one that comes with the kit as the maf scaling is done according to that.
Resizing that can do all sorts of things to afr's.
[/QUOTE]


Good question! I'll post up pics of the new intake tonight, vs what came off of the car. I don't believe it touches the airflow sensor, but that'll be a good thing to confirm.
 

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Discussion Starter #20
Here's some pics of the new intake next to the old one... seems like the MAF chamber is untouched, but everything immediately past that has been modified. IMG_20191121_201727213.jpg IMG_20191121_201848237.jpg
 
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