hi there, looking to buy one soon, was wondering what mods i can do to it to make it fast to 60mph,
decat with a straight through
smaller s/c pulley
cold air intake filter
and a remap what bhp am i looking at approx? thanks
also what year should i look for to avoid all the ones with the recall problems. thanks

 

03 through 08 STR's are all just fine. Be sure the car has a clean CarFax and service records. Don't de-cat but do place in hi-flow cats, replace center resonator with a Magnaflow dual inlet/outlet muffler with built in x-pipe. After the Magnaflow center muffler, maintain the stock 2.25" pipe and rear boxes. You can choose either a 1.5 or 3 lb pulley. Place a K&N air filter in the stock air filter box (avoid open air filter elements). You can easily place in a Eurotoys low temp thermostat. Go with the soon to be developed/released low restriction air intake tube. Send the ECU out to one of the UK ECU tune outfits. You can also send the blower for porting too. All mentioned will likely allow the already stout 400 hp 4.2 to develop 75+ additional hp and torque.

 

bfsgross, that's exactly the info I need to plan for future power increases, based on forum-recommended, proven steps. When you have a moment to spare, could you give a rough estimate of the parts cost and labor needed for each of the steps below, maybe with the name of a trustworthy supplier?

Low restriction air intake tube.
Blower porting.
Hi-flow cats.
Center resonator with Magnaflow dual inlet/outlet muffler with built in x-pipe.
1.5 lb pulley.
3 lb pulley.
Low-temp thermostat.
K&N filter.
ECU Tuning.

I do have an idea of some of these items, but it would be really interesting to see everything together. Hope I'm not asking for too much.

 

A soon to be released air intake tube may cost as little as $125. Watch for forum member qwiketz.
Magnaflow hi-flow cats $175 pair at Summitt Racing and various other vendors.
Magnaflow dual inlet/outlet muffler w/x-pipe I believe is $85 Summitt Racing, etc.
Eurotoys low temp thermostat $35
K&N air filter $44 at local auto parts stores or Summitt Racing, etc.
1.5 lb pulley I recommend the aluminum unit from Mina Gallery $175, mention to Chris this forum or Dr. Seth Gross sent you. 3 lb from Eurotoys, $175 if mention this forum or my name too. Purchase both thermostat and pulley together for deeper discount.
ECU tune $995 (U.S.) likely 500 Euros. From outfits in UK (Paramount?). I forgot the shops but just use the forum search feautre to turn them up.

 

Your probably going to want to do some preventative maintenance as soon as you get it...Update the alignment specs to prevent tire chewing inner tire wear, replace the DCCV and coolant overflow tank as both are an extremely high rate of failure...

 

Thank you both. My Jag will want for nothing as far as preventative maintenance is concerned. But that does lead to more questions...

For a car with a reputation for engine heat-soak, surely a low-temp thermostat would always be preferred? And those black plastic panels that seem to cover everything in the engine compartment must be trapping the heat and making the situation worse?

Before the STR I had a Saab 9000 Aero for 13 years. Between ECU tuning, larger turbocharger, new intercooler, 3" exhaust with race cat and bigger air inlet pipes, was able to increase the HP from 200 (factory) to over 360. There was a whole lotta heat generated but the engine would always cool down rapidly when I parked the car. Not so with this Jag, seems unable to shed heat quickly.

 

The S-type is no better/no worse for heat soak than any other comparable car. Lowering coolant temperatures does precious little for lowering inlet air temperatures= and that's where the potential power increases are. Deleting the factory cold air inlet and substituting an under hood inlet is a step backwards.

From a thermodynamic point of view, running the engine coolant at a lower temperature than maximum is directly robbing potential power. The heat energy generated through combustion is increasingly diverted into the coolant- instead of pushing the pistons.

 

IMO, Mikey makes a valid point regarding the low temp thermo potentially combustion chamber thermodynamics for the worse. As far as those using the low temp thermo (including myself), we've noticed that the operating temperature eventually equals that allowed of a stock thermostat. In this regards, my verdict is still hung on wether the low temp. thermostat is of benefit or negative detriment. Who knows, I may return to a stock thermostat myself. This is food for fodder, as we need dyno tests with the various modifications.

 

My understanding is the danger, if any, is more related to the ECU's inability to control emissions at lower temps, because the software assumes the presence of a standard thermostat.

Someone ought to have a chat with those naughty people at Eurotoys for doing bum research and making false claims about performance improvement. Or are they, in fact, correct?

 

Ya never know?

 

Robinb - some real-life Eurotoys dyno sheets for the STR would be interesting. Know any?

 

Not me, I'm too new to this Jag game. I don't know if the forum members with low-temp thermostats have any info. Eurotoys have an axe to grind and may not be prepared to supply "confidential" real-life info.

 

Could someone point me to the Eurotoys site showing what claims they make?

 

Let me google that for you

 

I tried to find any data from Eurotoys about STR "ECU" (*) tuning and from their web site it appears they don't do it.

No sign of dyno sheets for the STR either.

(*) using E=engine here

 

The joke's on you I guess........

 

The Ecu tune is listed on eurotous web site. Gains are speculative at best since they have no data or proof. Someone could bit the bullet and try it and dyno before and after. Won't be me since they don't have a NOS program.

 

I believe the low temp. thermo causes the rpm (motor) to ramp up and down for a while until it reaches full potential operating temperature. I'm going to return to stock thermo. and see if this is the case.

 

Mikey are you saying a cool motor doesn't make more power? Forget the forced induction even an NA motor will make more power when it's cooler and I don't mean the intake air but the block/coolant.

We use to run cool cans in pro stock to keep the motors cool. You can see a diffrence on the dyno for sure. Now the STR is going to be a slight change but the larger motors are easy to prove the theory on since a small change makes a noticeable diffrence.

 

I expect you're right but I couldn't find it for the STR so please point it out. I found a "call us" thing which is not exactly any use at all for me and in any case didn't even mention the S-Type.