Avos:
To say I have no idea about the effectiveness is a bit of an overstatement, given the boost gauge is now reading 2 psi different. To most people, that would indicate a change of approx 2 psi.

My boost gauge read +2 lbs higher with my intake mods. Are you saying that the difference in the boost gauge readings is not a measure of effectiveness of reducing vacuum?

If not, where else did that + 2 lbs come from if it was not reducing vacuum?

It seemed perfectly correlated to me that exactly just after adding my intake mods the boost increased 2 lbs. It was so correlated that I am interested to hear how you explain that it was not causal, or how it is possible to say I have no idea of it's effectiveness.

I used a gauge to "gauge" how effective the intake was at reducing vacuum at WOT. Measuring the delta in boost IS the measurement.




XK:The cobrahead in my stock 4.0 was THE bottleneck of the stock intake. I'm glad to hear they improved it after the x308 style

 

Measuring the vacuum would have been a good way to prove if for instance the cobra head would have been bottleneck, and also by how much.

It will also show how much improvement is still there to be made, which a boost figure wouldn’t tell you. Next to that vacuum is easier to read than the boost with all the possible spikes there.

This is so simple and easy to do, but if you don't want to know (am not asking you either), then just don't do it!

 

Avos,



So then to clarify, you ARE confirming that if my boost gauge showed a +2 psi increase after the mods, that this therefore 100% completely confirms that I therefore reduced 2 lbs of vacuum at WOT, yes? If not, I'd really like to hear your reasoning.


The video of my 0-100 mph run clearly shows that, at least in 3rd gear, where the tach isn't wrapping up soooo fast, that there are NO spikes in boost, nor is there any drop off in boost. The boost keeps climbing all the way to redline.

0-100 mph video here https://www.jaguarforums.com/forum/x...19-psi-108378/

The cobrahead necks down to the smallest dimension AND is where the airflow changes direction 90 degrees on a sharp drop off, so are you suggesting that it is even possible that it is not the most restricting point of the stock intake tube?

 

If that is all you are focusing on, you are missing a big part of what I have just said imho.

But to answer your specific question: I can’t validate your results, so I can’t confirm anything there. However as I have always posted here in general and also to you specific, you need to reduce vacuum to get more power, and that is what you have followed, good stuff. If you have reached close to 0, you know that there is no more need to improve anything and you can use all the right parts and not have to overdue others (bigger isn't always better). But again that is only for those that want to know (not meant negatively…).

If you want to know if you have reduced 2 psi (which is 137mbar), then you need to measure that, I can’t make it any easier. And no, I don’t need any video or other proof, if you say you have measured 2 psi vacuum drop and have gained 2 psi of boost, than I trust that that is what you have measured.

With regards to the cobra head; I have had already used the smooth bend somewhere 2008 or so (yes with silicone tubing), but don't have any vacuum measurements anymore, as my prime focus was to work on the bigger intake pipe with bigger maf to support the TS kit.

The prime advantage of why the cobra head was used imo, is to slow down the air and via the small bellmouth formed (iirc as its a long time ago I saw that one) allow air to easier flow into the TB.

I have no experience anymore with the eaton setups for a long time now, so can't tell which part has what specific effect at certien tuning levels, but with my limited flow knowledge I would also lean towards changing that cobra head and go for a smooth bend to keep the airflow speed also the same.

Bottom line, I would check it 1st via taking measurements to see how effective changes are, at least that is how I measure anything I do with intakes. This is the cheapest easiest way, before going to a dyno to confirm what the actual improvement is in terms of rwhp.

 

Aaaaand on a lighter note........ Fitting a set of velocity stacks with a plenum would be quite a feat on an XJ or XKR.......


But on an XK8 or XJ8......... Now that is more do-able

 

Practically speaking,

By going to a 92mm MAF instead of 75, having a 4" to 3.5" intake tube, having bored my TB from 75 to 82.5, and port matched the elbow, and ported the inlet to the blower, the existing parts appear to be maxed out as to what they can deliver.

Again, practically speaking, since I am seeing ZERO drop off in boost, and actually the contrary has been proven via my video, the boost is still increasing at redline, so the intake is doing it's job of not being overly restrictive.

Again, practically speaking, this has reduced the vacuum as much as possible with the stock, but bored, TB, and at a low cost. Again, practically speaking, there is no more improvement to be made on the intake side without going to very expensive aftermarket parts.

Whatever the amount of vacuum that may or may not remain in the intake track at WOT, at this point, practically does not matter, as it can't be changed, except for going to really expensive different parts, it is not changeable.

Our methods obviously differ. What I did with my system was to try to find out where the diminishing returns are, how things perform in real life, and I have now successfully completed that journey.

I added 4 psi without spinning the blower any faster, then added another 4-4.5 by adding a lower pulley. I have no heat soak, and no drop off in boost. The car, on video, ran a 0-100 in approx 10.5 seconds. The proof is in the pudding that these mods deliver, period.

To anyone who comes to this board looking for info of what really works vs theory, I suggest the intake tube, like the one posted in Dan's thread as the best bang for the buck and the first mod to be done.

 

measurement along the intake tract is the best way of selecting or confirming the required changes.

simple and cheap to do.

either use a magnehelic differential pressure gauge, $50ish on ebay, or a pop bottle, a tea bag, some water, a yardstick and some clear hose. the tea bag is for coloring the water. if someone reuses a teabag and has the rest lying around, then the cost is zero. that's pretty cheap knowledge.

lots of in depth articles on the subject at autospeed.com where the author has made a regular practice of measurement before and after intake modifications on both naturally aspirated and boosted vehicles.

and no, a boost reading is not the same thing as reading the restriction.

 

Sometimes I wonder what the world would be like if WaterDragon and Avos worked together, instead of arguing over which one has taken the most irrelevant measurement.

You guys have both achieved fantastic results, following two very separate paths. From what I can see, you're both as guilty as each other for only posting some measured results, rather than others.

At the end of the day, having every modified car on the same dyno with before and after reads, 0-60, 0-100, 1/4 mile times, vacuum readings, boost readings, intake temps, exhaust temps, flow readings, flux capacitor readings etc etc, is never going to happen.
But when someone asks "have you measured this?", could it not be taken as a personal threat to your manhood, and instead as constructive criticism?

Can't we all just get along?

 

Good points Grandell.

But please understand I'm not taking this or myself, very seriously.

I don't need any validation from my side. I was just playing the game of trying to box Avos into a corner to see if he would answer my specific questions at any time, and being entertained by his posting about something slightly different, evading direct answers, or even funnier attempts at diversions such as posting videos of bouncing ***** and the like.

No worries or stresses on my end. Its all in fun from my side.

You'll notice the direct questions are not answered directly. That says a lot.

 

Sad that you always drag this into the negative.

 

Yip, this is exactly what I was talking about, especially when his original reply was a lot more civil

 

Avos, "You are always trying to prove me wrong"

WaterDragon, "No I'm not"

 

If I ever get my x308 going any time soon I can always dyno it with a lower pulley and stock intake vs lower pulley + one of these custom intakes. I'm real good friends with a independent shop nearby my house and he has a dyno jet. I really believe the flow does increase the cars performance.

 

That would be great! The more evidence based info the better.

 

seems that today we can JUST go to the JAGUAR dealer and buy 555HP, and chip it to 600hp!

then the guys can say,ha-ha , mines bigger than yours, so there!!!!

"boys and there toys"

 

The XJR is the daily driver.

This kitty is the toy
This car is all go and some show. This is with the new "bundle of snakes" exhaust. Pantera GT5, affectionately referred to as the "PoonTerra" in my family. That is a stroked 408

It takes more than just 555 HP to keep up with this on a real track. You can buy some amount of performance, but on the track, you have to know how to use it. Just "check booking" one's car doesn't help once the flag drops.

"Well" over 500 HP and currently at 2700 lbs, goal weight of 2500 lbs soon. That translates in to "goodbye" to the New jags, even with a chip.

 

That looks like a monster, WD!

 

WD, is that a carburetor on that engine?????

WTF

 

Yes! a 830 Holley. Simple, yet mucho effective at making the power. NEVER gets a "restricted performance" message

This car is not about gas milage

 

Not to threadcrap on Dan's thread, but here is the car after warming up. Detomaso Pantera 408 windsor with 180 headers,quick little rev - YouTube

This car is now officially my brothers. He built the whole thing over the last many years. Happy Birthday Bro