On a cool morning my xk ( and every other vehicle I've owned since the 70's) loses a little to a lot of power as it warms up.
Before detonation occurs and sets up a different lookup map what temp sensor has the most dramatic affect on timing? Water, air or what other?
wondering outloud if I added water injection to my na xk it would help much with my typical 90~100f days this summer.
WJ

 

That's the characteristics of any ICE motor. As the ambient temperature rises the air is less dense, you get less bang.

Are you running high enough octane rating in the fuel?

Water injection will not do much on a stock NA motor, in fact you are going to loose power with or without a tune. There is only so much room in the cylinder to suck air into. You add water and you are reducing the volumetric area for air to enter and get compress and go bang.

The only benefit of using water injection in a NA motor is all that water will turn into steam and clean the tops of your pistons.

Water injection is only beneficial in a modified turbo/supercharger, ie running more boost than standard. You still need to work with a tuner who has experience in water injection tuning. Slapping water injection by itself you will loose power.
My old Toyota MR2 Turbo was tune to run 20SPI boost with a Greddy turbo with water/methanol injection and Haltech ECU. I spent way too much money chasing HP with diminishing returns.

 

I have a bit of experience with turbos, sc, etc...and thanks for the overview.
back to my question, which sensors have the largest Intial input (inpact) into the timing retard?
wj

 

on startup i think only air flow is the big variable. i'm no expert and i haven't memorized the technical manual on our engine yet (you can find it on our forum btw the name is "NP10 Complete Manual 4-15-09.pdf") but air temperature is not controlled and knock sensors are more important than air temp sensors in retarding timing once the AFR gets out of whack, i'm pretty sure.

pretty sure water temp is never going to be a factor. you can start just about any engine up with no water at all and run it for half a minute, rev it all you like, and it will never retard the timing, it will just start to melt.

our XK's do have oil temp/pressure sensors though, and those ought to be factored into timing somehow, because the timing is adjusted with an oil cavity in or near the intake cam gear. so in a roundabout way, running without water would overheat faster and therefore cause the oil to get too hot which may retard timing -- but that still has nothing to do with startup, really.

and, i would even wager the startup is partially "scripted." the ECU probably does not let you have more timing for a certain duration whether the oil gets to temp or not.

but if you must have an answer, it's air, not water.

 

doublechecked and the manual strongly implies the MAP is more important than the MAF sensors although it doesn't explicitly say the MAF sensors are completely ignored, it says they're secondary.
IAT is read off the MAFs. so yeah pressure then not flow, and this actually makes more sense than what i said now that i think about it. but the short answer is still "air."

edit: btw MAP not to be confused with TMAP which is on SC engine only

 

Back to your original question, Yes, Water Meth Injection WILL drastically lower intake temperatures and result in More Bang. As a large side benefit, it will also clean your intake valves.
However......
If you use a larger shot of WaterMeth, you would need to figure a way to tune it for best results.
OR, if you use a smaller shot, you will get whatever the ECU gives you with a lower intake temperature while still cleaning the valves.

 

thanks jons, appreciate the info.
wj

 

ceejay, I doubt there is much ++ hp available with tuning the na xk, was suggested maybe 15hp+/- not worth tuning in my book but if I can simply retain some of the low temp performance as the summer warms up I'm willing to play with the water/meth a bit.
wj

 

Yes, it is more effective on a supercharged engine. But heck, I'd do is solely for the Valve Cleaning...... which I will do soon.

 

not sure that's much of an issue on our MY's. More of a direct inject problem I think?

 

I totally missed the year. My bad. Well, still, I'd do it to clean valves mostly.

 

We got a 13.7 101.5mph out of a tuned n/a ( x pipe & 100 cell cats) no quite xkr stats but a lot more respectable then the standard figures . So tuning definitely worth it

 

On 4.2 cars there is plenty of power available in ECU tune. Up to 100hp on supercharged and good 30-40hp and more in torque on NA version of that engine. PM me if interested can help

 

Well Alex, prove it!

No changes to exhaust, intake, etc…just a software change.

Dyno before and after…I recall that a customer of yours couldn’t verify a 15hp improvement on the 5.0.

This is a public forum, let’s keep it public.

wj

 

If we are discussing 4.2 cars, everything applies what I said above and the car will be significantly faster even with the NA version. You're welcome to take it on a dyno or a a track after we tune it. In Everyday driving you will notice a good amount of power gained, you won't be guessing if it made a difference or not.
As to the particular 5.0 NA in question we don't have much data from that car , as the customer couldn't log parameters required , so left that as is. But from what I have seen, suspecting Other issues preventing power gain. We just don't run into NA5.0 getting tuned to verify gain.

 

Alex,
I’ve been around the block from the good old days before things could be verified and information collaborated.

So, just to play in your sand box a bit longer;

My step son had a turbo diesel VW (from diesel gate era). He purchased an $800 ‘chip’ that was guaranteed to deliver some amount of extra power along with better potential fuel economy. The company eventually realized that they couldn’t improve on the dirty fuel map that VW had implemented and what did they do? They refunded monies to anyone that had purchased their ‘upgrade’. That, in my book is a reputable company.

He now has an XE (SC v6)with a paramount ecu upgrade. He had his car dyno’d: stock = 315hp, same conditions after cool down + ecu tune=410hp. Later added pulleys and is bumping 465 until heat sink takes its toll.

So now to you claims…since you ‘know’ that your tune will add 30-40 hp, prove it. How do you know? Dyno numbers? Show them. I don’t want ¼ mile times unless they have a higher trap speed than stock.

How about you offer to tune and then if expectations are not met the monies are returned? I’m certain there are more than a couple folks here that would welcome that assurance.

Wanna play? I’m talking about a stock xk 4.2, nothing else changed, added or deleted.

I’ve spoken with, communicated with over a half dozen companies and I typically get two types of answers.

1 There is @ 15~20 hp to be gained on a totally stock 4.2 and it wasn’t worth trying to eke out another 5 or so. Fuel curves and ignition can be modified, based on owners typical weather conditions, to achieve better acceleration but at the cost of a lower top speed…so less HP at peak but maybe better driving characteristics while driving in their area.

2 They can add 30-40-50 hp with a tune, even more with exhaust mods. They can never supply verifiable date to support this and the internet is awash with disgruntled individuals that bought the hype.

No NDA needed!

I won’t be dragging this exchange on and on. If you can supply this verifiable info great, if you are willing to tune based on the hp gain, great. If you want my money you’ll need to earn it.

wj

 

IM not here to blow smoke up anyone's butt here 😆 Do I have Dyno and track times for 4.2sc ? Yes we have plenty of both, gains up to 100hp recorded. Do I have them for 4.2Na? , Have data confirming the power gains mentioned via data loging but there is no track time from my customers or a dyno on non-supercharged 4.2 cars, just not that many customers interested in doing it. There's a few gurus around the world that have figured out these Denso 4.2 cars to the extent that I have. And as to the gains on NA 4.2 ,Steve above mentioned the time that he is running on his tuned 4.2 NA car indicating at least 30 - 50hp gain. Not a lot of Na cars can gain a good amount of power from just an ECU tune but 07-09 4.2xk cars with the proper Tune are an exception. My 08 tuned Xkr running faster than 556hp 2012 cts-v a lot more videos on the channel including dyno ​​​​

 

Apples, oranges!
1/4 mile has many variables...Steve has done great but also has x pipe + 100 cell cats.
Your continued reference to xkr has no bearing on this discussion...the lack of verifiable dyno data on na 4.2..ends my participation in this discussion.
wj

 

Il stand behind my claim and I'm confident ECU tune on these cars would be the best bang for the buck and the biggest gain unless you go nitrous for example and FYI track data just like any dyno should be used with the correction factor for altitude density. Either way I need somebody to do the DYno on 4.2 Na car , can discount the tune to help with the Dyno and il guarantee at least 30 crank hp or Torque gained

 

Alex,

I’m not very likely to take you up on the offer but since you’ve thrown it out, maybe someone else will go for it.

My plan has been and is still to find an XKR this fall, but if the monies don’t accumulate quick enough I may do a group of upgrades to the XK, time will tell.

Just to be clear, you are ‘guaranteeing that your tune will increase crank hp by a minimum of 30hp over whatever the stock engine produces? No other changes (exhaust in particular)?

And without getting into the details…with a safety margin as to A/F ratios…detonation detection? Not looking for a hand grenade.



wj