Usually you can expect 3-4hp across the powerband. Not really that much for the cost.

 

Jaguar 4.2L Multi-Piece Supercharger Pulley Kit

50-60 hp gain.

 

1320racer, have you done the intake elbow as well? That was dyno proven for 10-12HP
https://www.jaguarforums.com/forum/s...e6/#post519314

Regarding the Maxbore, it's $120 for the service plus shipping (and your time). Even if that only gets you 5HP it's still a cheap mod.

 

Ya but no dynos to prove it. Kinda like the ECU tunes, people promise a lot, but can't prove anything.

 

Frankly I don't believe it. The Eaton is known as Heaton with good cause.

 

End of the day, the eaton can only flow so much air. This is evident when you look at any of the upgraded pulley dyno graphs posted. They make more power around peak torque, but by redline, they've run out of steam, and are making more or less the same power as without a pulley.
At best, vendors will advertise 'peak' gains, but one glance at the dyno sheet goes to show you those benefits are isolated to mid-range/torque numbers.

1320racer's observations are right on the money when describing his 2.6lb pulley upgrade; he says, "the smaller 2.6 inch pulley helped just a bit when launching but diminished top end horse power...

We can make small gains through efficiency improvements (read: how the motor breathes), otherwise, any substantial gains require pushing MORE AIR, which just isn't going to happen on the already maxed out factory Eaton supercharger.

Same goes for chips/tune's on mostly stock STR's. A/F ratio is a *bit* on the rich side when stock, but the A/F traces on modified dyno sheets appears to have little to no room to lean it out more safely, and even then, gains through A/F tweaks at that point are minimal. Ignition timing is trickier and dependent on fueling too, and the factory computer seems to do a good job optimizing at it as is. Theres no such thing as to keep throwing timing at it and it will keep making more power on a given fuel. Eventually, you hit the 'right' timing profile and that is it.

 

+1 (an alternative being cooler air, so better intercooling etc)

 

Avos, you felt a 90mm TB was needed to support your 600+ chp 4.2 w/TS?

 

It certainly helps.

 

Larger throttle bodies are a standard aftermarket performance item for other makes, just a few example for Fords;

Mammoth Supercharger

Ford BA-BF V8 Big Mouth Throttle Body Performance Automotive Enhancements

Check the prices from SS Inductions in Oz, $675 for an 80mm TB (stock being 75mm) and Maxbore does it for $120 or so....

 

hmm. What to do about the two TPSs?

Seems to me they make this very hard.

 

But i'm not saying fit the Kenne Bell or SS to the Jags, just to show that a bigger TB is a normal modification on modern mainstream V8 engines....

Two TPS? There is only one, & besides, we have found an aftermarket supplier of the OEM part!

 

Wonder if a 90mm TB would "help" on our STR's as they presently sit?

 

Er... wrong, surely? One TB, 2 TPSs. Used for safety. You can see them in the Electrical Guide as TP1 and TP2, in sich as fig 03.5

 

You mean one of these



It's two separate sensors in the one housing....

 

So the bigger TB... does it have the same sensors as the OE TB? Or what? (The PCM needs to see the right signal from each, and they're different on purpose.)

 

Don't know, I would say it would be too expensive for what you can get out of the Eaton, as that is your main problem.

The boring out is cheap enough to do and will certainly help a little, but results will depend on how much more airflow you have over stock obvioulsy, and the TB is just part of the intake.

 

That would be a question for Avos, since he is the only one who has fitted an non-OEM TB...I would guess that the OEM TPS needs to be mounted on the new TB.

What I was trying to explain, is that the factory TB at 75mm, can be modified to 80mm by Maxbore. That would be the same housing & TPS as original, so no compatibility problems, just more flow.

SS in Australia sells an aftermarket 80mm TB to replace the factory 75mm TB on the V8 Falcons, for $675. So it's an example of why the Maxbore looks like a good value proposition, and that a bigger TB is a sensible modification worth looking into, it is being done on other engines (& it's the next mod on my list).

A bigger TB, along with improved intake elbow (i.e. Qwiketz, Mafioso, etc) is going to be a winning combination.

 

The Falcon doesn't use the same Denso PCM as the STR does it?

 

Unfortunately no, and Ford uses a different TCM for the ZF 6HP26 too, we can't use any of the fantastic aftermarket goodies the Aussies have...

But it is still a good example of what we should be aiming for....