If I put on a 4 lb lower (2002 XJR 4.0 Eaton M112 4rth gen) would a good water/meth injection system be enough to keep the IAT at a good target??

I'm curious how much extra heat would this make (trying to decide what mods to make on my 2002 XJR 4.0) and want to not grenade the motor.

The only other immediate mods are:
Delete middle muffler (should I go x-pipe, or keep them separate?) then some borla mufflers downstream, and keep the stock tips.

K&N air filter, remove silencers from stock intake tube, remove fins in side top of air cleaner box. (small mod, but hey, basically free)

13 degree cooler thermostat

Suggestions?

 

Here is a calculation I once made to give some idea of how the temperature will increase based on the graphs from Eaton themselves:




This is still assuming your interoolcer system is capable to remove heat as fast as it gets it, but that is not the case. You will see that the circuit will build up heat, which again causes powerloss. So best to go for a water/methanol kit (spray after the supercharger) or chiller killer or even both if you go this route. These will help to retain the power for longer, and also help against detonation of course.

Don’t have an outspoken view anymore regarding colder thermostat temps, I am using a 83 Celsius one iirc.

Definitely keep the exhaust sides connected, either an H or X-pipe, also 200 cell cats will help a little.

A K&N Panel filter is certainly recommended, it will help a again.

You could bore out the TB as well, on the AJ26 engine you can go to 80.5 mm (from stock 75mm), and I think the AJ27 (which you have) will be able to get the same. I have had one made by www.maxbore.com, they have done a good job and can recommend them. Of course also port a little the intake elbow, but it can be matched.

Another thing that can help is a camshaft re-ground, www.catcams.be can do this for instance, but will cost of course as you the work is also expensive to do it (unless you can do it yourself. You could expect between 3 and 5% airflow gain.

 

What a great board this is that I may get such responses. Love the charts. Your prize is.....more questions

I will buy the killer chiller ( I'm assume you prefer the one that runs with the a/c compressor and not the all electric? )

May I also ask what specific water/meth injection unit do you recommend and running what mix of fluids?

Is there some estimated computation for lower temps = how many HP per degree, all things being equal. If my car was bone stock, but I added the Killer Chiller and water injection, how many HP gain could I expect? Are the pulleys worth it in the end? What pulley set up would you recommend. Is the 4# lower pulley the way to go (2002 XJR has 4rth gen M112, right?), or would you recommend some other pulley?

I would only run the car hard (high boost) for short periods, not more than 1/4 mile. With an uprated pulley, would adding the Killer Chiller and injection kit likely keep temps under control under these short time demand conditions? Would this mean I could add back that 10 hp estimated loss for extra heat?? and then likely gain 26 hp vs 16 overall?



I will also order from Maxbore.

I'll do the xpipe with the stock cats (California emissions are toughest) unless I can find cats that will pass California smog for sure. What diameter x-pipe for the 2002 XJR?

I could not get the cam grinding website to work for me. What hp benefit would 3-5% increase in flow estimate to?


See pic of new XJR hottie on the left, and the one that started it all XJ8 on the right (now my wife's)

 

Have no direct experience with either Meth/KC, so can’t give any numbers, maybe others have, am also not planning any of these on my car.

The stock Airco unit isn’t able to take out all the heat once under boost, so when you go for the KC, makes sure you add a tank somewhere so you can create a good buffer of cold coolant.

Without cooling at the end of the Ľ mile you have lost some good power, how much you can save with either of the above I can’t tell, but I do believe they will slow down the power loss.

The ECU can pull the timing by as much as 4 degrees (at least that was what I witnessed on my car some years ago), which could be 20 or 30 hp, but that is just a guess of course.

The pulleys will bring the power on earlier on the RPM scale which will be very noticeable, and this is also why most say it is certainly worth it. But when it comes to measurements one could get disappointed, as you need much more changes to fight the heat and the increased power consumption of the Eaton (as you can see in the graph it goes up more exponentially then linear with speed and boost).

Make sure you do a good before dyno, this will already give you some idea if the base car is in good condition, this can be priceless info later on…

 

I have so much to learn...

These pulleys sound like they may be more trouble than they are worth...

I think I will start small and safe with the lower temp thermostat, killer chiller, water injection, K&N, Maxbore ported TB, tighter belt on SC, x-pipe, delete one set of mufflers, switch to Borla rear mufflers, keep the stock tips. I notice the car on a cold day or cool engine has lots more power, so I will first try to re-create that with the cooling systems of the KC+water injection

Any recomendations of who to use for an ECU tune? I live in California if that matters...

Then I'm going to continue to do lots more research....

I will do a before dyno

 

The road itself is already half the fun, so enjoy ;-)

ECU tune should always be last as you tune for a specific setup of course. A sharp tune for a stock car could be outright dangerous/counter effective for one that has more mechanical mods.

So I wouldn't do anything, and would advise to do similar as I have done, increase boost and use up the safety build in the stock ECU.

 

How much boost do you recommend (100% stock right now)
I am going to do the killer chiller and water injection, likely snow Snow Performance : Stage 2 MAF Boost Cooler unless I hear there is a better one

 

Have no experience myself with water kits, so can't comment there. You only must make sure that you spray after the SC and make sure that both banks will get a similar amount of course.

As you know I can't recommend the Eaton at all when it cxomes to performance ;-), the higher you go in boost/turn the Eaton the more power it consumes from your engine (that is besides the heat) until a point that you actually would start losing power by upping the boost more. But as you are twisting my arm here, I would say around 15 psi max.

 

To add, to get the maximum out of any supercharger charger setup so also the Eaton, you should work just as well on the induction side, so try to drop the vacuum as much as possible, as boost + vacuum = power consumption of the supercharger from the engine.

 

I have a 3.5" air intake pipe that will help you get more air in.



Here is a photo of cold you can get your charge coolers with a Killer Chiller

 

I just found one with a more rounded bend where the air makes the turn into the throttle body.

 

If you are interested call Mike Casey @ Enigma Rod Shop 978-667-6060 He is the fabricator who made them. He runs a custom Hot Rod shop north of Boston.

 

I called him. He has them in stock $625.00
This will go on my wish list and when I do my build, I will likely get this type of tube. These intake tubes seem to be evolving so rapidly, hard to say who will have the best in a few months.