please help!!!!!



well long story short... my buddy has a 300z and this other guy has a subaru inpressa .. i got the challenge last summer and i have not been able to find a good mod for my beast..mmm.. so i talked to my jag mec.. i asked about getting a upper and lower pulley upgrade... and he responded wit.. jags engine is very fragile and most aftermarket parts will break down the xjr engine.. so now im confused??? i want to mod my beast but i dont know what to get??? so.. yea... mmm... i pretty new to the site and i have read someof your post... i know u guys are pretty high speed so.. please help.. and yea.. this is what i wanted to do:

1 k n air intake
2 upper and lower pulley upgrade
3 borla cat back??

if there is something better or is not good for the car i know u guys will help i have not race them yet.. i had to get my supercharger coupler replaced.. help me beat these... *******s!!!!!!!!!!!

 

Port your supercharger, have them put a 3lb pulley on it = 60hp $1500

Lower pulley = 15-20hp $600

Intercooler $1000

ECU = 25hp $1000

cat back exhaust = 10-20hp Borla/Mina $1000+ Magnaflow w/magnaflow xpipe $500

K&N drop in filter = 5hp $60

Limited Slip Diff. = $1300

And hope your transmission holds. Anything over 450hp and its a crap shoot. I would do the porting the supercharger with a new pulley, exhaust, filter and ECU with lighter rotors, carbon fiber hood and trunk and you should get to 0-60 at around 4.3-4.5.

 

excelent!!!!!!!

 

Best thing to do is the rebuild and porting of your supercharger with the new 3lb boost pulley on it. 60hp for 1500 bucks and you have a new rebuilt supercharger. The K&N filter is a great little 5hp boost but i'd do that only if you are going to do the exhaust so its all nice and free flowing.

ECU would be nice, but its $1000. Worth it if you have the money.

Eurotekdesigns have a stage 2 pulleys/ECU(65hp 75tq) for $1700, but the supercharger porting option gets you 60-65hp, a new part, more efficient and doesnt force you to get an intercooler.

Look at Paramount Performance, Eurotoys and Mina Gallery for the engine mods. Paramount and Eurotoys are better. And Disc Italia or EBC for the rotors.

 

@Princemarko
Do you have any dyno figures to substantiate of the suggestions you have made?

 

so if i do the porting of the supercharger, intake, exhaust and upper and lower pulley.. would that put me around the 400hp?

 

PSE Superchargers technician quoted me the 27hp for porting and another 30hp with a 3lb pulley from Eurotoys. Paramount has dynos on their ECU and filter, i just spoke to both this week. Obviously, you'd have to take their figures with a bit of skepticism as you would with any tuning company, but Paramount is a highly reputable company. I'm sure your twin screw conversion was a Eurotoys package? T

Paramount even modded an older XKR on Top Gear that Jeremy Clarkston took for a spin: http://www.youtube.com/watch?v=eth12U3m_8s

I'm going to the porting/pulley, filter and exhaust done soon and I will dyno it and give you numbers.

 

ok.. i think im going to do the same... so after all this is done what r the chances that a "engine code" or an engine problem can occur?

 

The porting and pulley for the supercharger will not give you any errors, the only thing that I think could are the filters and exhaust. O2 sensors, MAF sensors are sensitive.

 

If you are going to build for 30+hp buy an aftermarket intercooler and pump first. I used to have a 99XJR and did the upper an lower pulley, custom exhaust, and intake filter. I had the car dyno tuned for optimal power. I was only producing another 37hp with everything and the engine only had 43,000mi. The car was already in optimal shape. I was disapointed at those numbers. Once the car warmed up i actually lost power because of the extra heat that the stock intercooler couldnt handle.

At that point I was very disapointed and didnt even have the car tuned. I was going to again once I upgraded the intercooler, but things changed and I sold the car.

I have dyno slips somewhere in my garage. Off the top of my head Stock the engine only made a little under 370bhp and I was only getting about 320rwhp. With the mods I gained to over 400bhp and was getting around 340rwhp. It was a huge difference when the car was cold. when it warmed up it lost power below the stock numbers, I think it was 347bhp with the mods and I was getting below 300rwhp.

Im sure you can get close to the claimed numbers with the intercooler, but I know for a fact you wont without.

I will search for the dyno slips, it was only last year so im sure there near the top of one of my dyno day piles.

 

@princemarko
As you already know I made my own twin-screw kit, way before any other tuner had done (one of my first ones was already in 2006). Some of the tuners started making a kit after I had made mine, after they saw what was possible, though I never lifted the lid fully with the flaws I found, that have been solved now.
You just can't add all the fictive HP claims together, it goes against what I have learned, and I have not seen any creditable dynos to prove any of this.
For a stock car it is easy to tune the ECU, you do not need to be reputable for this, 20-30 bhp is possible. But that is a tune for a stock setup, not an overheated setup. You can also tune the car to the max, and risk your engine, not hard to do.

Hope you get what you want!

@najags9903
I had exactly the same experiences as you, my top end power came actually at the same level as stock with all the (h)eaton pulley mods, about 310 rwhp. Don't think you will gain much with a large intercooler; it will give you some extra buffer though, so better to make an extra tank of a gallon or so.
It took me many months of investigations as to why I did not get the extra top end power, as of course the seller (whom I will not name) claimed I should have gotten much more HP with the larger lower pulley, so first I thought it was something with my car.

I was just also extremely disappointed, and that triggered me to go the twin-screw route, and man have I shown that there was nothing wrong with my car ;-).

 

@AVOS

I really thought the stock intercooler would be able to handle more heat on the 4.0L.

This summer if all goes well I am planning to do a 4.2L swap into whichever year X308 XJR I can find in great condition. It will be the same thing though as I want to build the 4.2 up to around 450bhp. First thing I will do is a custom intercooler to handle all extra heat, so I dont loose any power.

The HP claims are far out there as any aftermarket company. They are based on the optimal conditions and brand new everything working together at 100%. No car that is driven will ever fall into that catagory.

 

Try not to make the intercooler to thick, as that will hinder airflow which is what you need. Best advice I can give is to place an extra tank in the circuit of a gallon, as that will give you more buffer before the system collapses under the (h)eaton.
Have done also some pump flow tests with all system components attached, and the stock pump flows about 5.4 GPM, and it would help to speed that up a bit. There is a Bosch pump with partno 0 392 022 002 (slightly larger the stock) which is also used in the bigger fords that flows about 6.2 GPM, very cheap and easy to install, here is a link:
http://www.siliconeintakes.com/produ...oducts_id=1001
This is by the way the biggest one available.
I do have another that flows 7.2 GPM, but that one is much more expensive and bigger.

 

@avos It would be great if your setup is bolt on. The Eurotoys setup requires some machining which i'm wary of also.

 

Good advice and thanks for the link. Im sure I will be fine with a better pump and intercooler, as I just want a few more horses. Im not going to build a race car, I just want more power to move around.

 

Thank you sir for bringing some reality to this madness.