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waynef

TPS and Throttle opening question

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On Freescan the throttle can be set to ensure 100% open.

Is this Linear as in 1/4 open 1/4 throttle or can one set it to prefered set parameters.

The car is really agressive with the slightest touch on the gas in the lower 50% of pedal travel and I was wondering if this could be tamed by adding lower staged tps setting values? Ultimately when the car is over 50% pedal position I want the power to be spot on with pedal movement.

Waynef

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The output of the TPS is linear with respect to the opening angle/position of the butterfly.

The ECU digitizes it on 8 bits, that's 0-255.

Freescan just reads this raw value (which you also have access to) and just scales it linearly to display a 0-100% scale.

There is no way (intended/built-in) to modify how the ECU reads/interprets the TPS. Not that I am aware of at least (may be I am out of date ?).

Of course nothing stops you from trying to fool the ECU by putting some self-made electronic circuitry between the TPS and ECU, in order to create whatever TPS response/map that you fancy.

If you think the ECU response is not adequte/normal at lower openings, then something must be wrong and must be fixed, rather than tweaked.

Check with Freescan (engine stopped) than the TPS ouput is consistent with pedal travel. If it is then the problem is somewhere else.. create a new topic about this issue... ;-)

Edited by troutrou

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My SE was way out when I bought it - over TPS (24% at rest or something mad like that) - never felt any difference in power at all, if anything it stuttered.

I put this down to under/over fueling.

Check your throttle cable - keep in mind cold weather does this to cars, my SE feels as if it wants to rip your arm off as well in the pre turbo band compared to the GT3.


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Hi Jonathan and thanks for reply.

The cars always been like this and I did have Dermot ages ago take a look and he said it was set perfect. What i'm trying to achieve is a custom input at <50% throttle so that I can feed the power in gradually and then at over >50% throttle all hell breaks loose :lol:

Its just that where my Mrs reversed our family car off a mini cliff (Pics will follow and yes she is ok) i'm back to using my Esprit as daily driver and not likeing the aggressive nature of it :(.

Oh and incase no one else has mentioned i'm getting about 1/3 increase in distance by using Optimax so although more expensive it works out cheaper:)

Waynef

Edited by waynef

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Talk to PUK. I'm sure they used to be able to code the ecu chip to whatever the customer wanted within reason.

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For $1,000,000.00, no comeback and a complete lack of customer service as usual.


88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

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Wayne - yours is chipped is it not ?

I've not had a chance to look at the code but from looking at many chipped freescan cars what this issue of 'insane' acceleration is litterally the chip'sidea of unrestricting the turbo on spool up.

The car has, an ECU controlled turbo boost pressure system (like an after market boost controller) where the ECU controls air bleeding from the wastegate capsule to provide overboost - under normal operation the ECU feeds this in progressivly over the rev range. In order to overcome the 3k stumble it is my firm belief (and I have been backed up by 2 major chip know alls) that this overboost controll was basically put in the 'what ever...' catagory which makes the turbo spool up into overboost pressure very quickly - as oppsed to the standard car which is progressive.

This adds to the rocket assisted take off affect and a cheap way of making the car feel fast - in my opinion it has the reverse effect to a dump valve and the reason why people fit that - you're commonly asking the turbo to go from rest to max pressure (in chipped cars cases, OVER pressure by upto 40% which equates to much more that 40% extra turbo RPM !) in a much shorter time frame under acceleration.

Try taking a freescan of the car under acceleration and pay attention to wastegate DC column, mine very rarely gets above 75% yet still reaches max boost, in 5th the DC might hit 90% when hitting ~ 140mph (on the track day I did). On chipped cars I noticed the DC hit 100% almost instantly and that is what gives this insane acceleration as the turbo has no restrictions at all.

Still trying with a few others on here to get a free'chip' program running so people can mess with their own chips.

This is the main reason why I didnt go for the chip in the car. I had the cash, I was ready to buy but when I read into it - cause/effect I didn't like the sound of some of the ways the chip done things.

My hope is we could, as a community, create our own chips and have people knowledgeable into developing differnt styles for different cars and of course not charging e400 for the privalidge everytime. I think the EPROM cost ~ £10 if that, programmer is £50. this would certainly help you make your own changes and preferences to the car at the push of a button as well !

Andy Whittaker charged £500 for the code/interrogation file which is needed to make chips, thats a small price to pay if you ask me - esp if you spread it over 20 enthusiasts.


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Would it preferable to alter the mechanical aspects of the throttle action using a different shaped 'cam' that the cable wraps around rather than getting involved with codes etc?

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Probably as much if not more effort, the issue I firmly believe is in the chip which compensates for the 3K stumble by letting the turbo run away with itself.

By making different cams for the butterfly (which as I say is an awful lot of work) you're just 'swallowing a spider to catch a fly' type of problem solving.

What you could do is try bypassing the overboost solenoid and plumb the feedback from the turbo straight into the wastegate capsule, that way you'll only get 0.65 boost but be able to ascertain where the problem lays.


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Some interesting comments and yes my car is running chip number 5

Well to be honest i've bypassed the overboost solenoid in the past and it cuts the performance in half.

To be honest i'll live with the gut wrenching aggressive take off and just get the Mrs on the road hopefully by this weekend as just put deposit on her new car so hopefully will get my commute mobile back :lol:

Its only when you get into daily driving the Esprit you realise how mush hard work they are. Great fun though and thats even after 5 years of ownership :(

well about to get in her now and rip my arms off again up the A3M

Waynef :wallbash:

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It's a supercar afterall, I've not had much behind the wheel time of the SE/S4 vs the GT3 but the GT3 is a lot more two tone.

You can drive it like a little 1 litre and pooter anywhere, or you can jam the throttle in and the thing rears up like you just whipped it.

I found the extra 200cc much more urgent and tugging at the reigns, begging to be thrashed - more torque for sure.

Dunno what to suggest other than moderate the right foot - try different shoes, I've 3 pairs of driving shoes and I do have my favourites for giving much better throttle control (they have very thin soles) .


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Yep, that was kind of the thinking Si. If you increase the amount of travel the throttle pedal has it will be much easier to modulate your foot's input at lower openings.

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Having stripped the trottles and the throttle cable as well as the pedal box I dont think you'll get anywhere near what you want with that idea due to the limited travel. Have fun though if you try it ! :(

Seems like a very complicated way of just moderating your foot :lol:

Edited by Jonathan

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I'll probably skip playing with the throttle linkages cams, cables etc as I might end up with a design like the Toyato Prius :(

Easy fix, replace the Mrs car (Picking it up tomorrow) and get my commuter barge back

Waynef

Edited by waynef

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Jon- Are you sure it wasn't a case of "Sudden Unintended Acceleration"?

Not sure if this applies to other countries, but here in the states Toyota is fighting a pretty big recall campaign regarding runaway Toyotas due to some issue with the throttle control.

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Oh and incase no one else has mentioned i'm getting about 1/3 increase in distance by using Optimax so although more expensive it works out cheaper :D

Have you documented that or is it a guess? I'm not sure even Shell expect that sort of improvement...


88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

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Well out of two vehicles I run on Optimax the Esprit S4 and my girlfriends Renault Espace 3.5V6 both cars are significantly more economical on tank range.

The Esprit on normal fuel costs me approx £20/day to go to work and back (this I know as have run out on one occasion :D ), a distance of 64 miles round trip. On Optimax £40 will see through 3 days of constant commuting this journey where standard would see me through just the two days.

The Espace is similar in the sense on normal it returns approx 19mpg, on optimax it achieves between 26 - 29mpg and tank range is extended by upto 70 miles.

Whilst I have not documented this my wallet would definately say this rings true as both vehicles go further with optimax than with conventional along with a heavy right foot :D

I'm not saying this is true of all vehicles as my Alpha 147 was terrible on the stuff with no improved running. I guess it is down to performance engines.

Waynef

Edited by waynef

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Keep a track of the mileage and how many litres you use, a simple spreadsheet will give you a comparative mpg figure (I use a free iPhone app, VehiCal). I honestly think Shell will knight you if you're getting 1/3rd more miles.


88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

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I do that on the Esprit just out of curiosity. I use propper shell business now and noticed.......eff all difference :D

Seriously it runs as smooth and as much MPG as when I used to use cheap sainsburys fuel...

I'll give it time though.


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Bibs i'll keep a fuel log over the next few weeks.

Ok a 1/3 is prob not factually correct but my commute is 64 miles rtn. £20 will get me to and from work before the fuel light comes on.

With optimax I can do the same journey but it'll get me all the way to work the following day before the fuel light comes on, an extra 32 miles.

I have however just put the standard exhaust and Cat on for MOT this weekend. The performance difference is not noticable with standard setup. Boring infact, i'll redo some actual figures once i get the sports exhaust and de cat back on

;)

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I've done 3 fills with V power and get ~average 20mpg from it on the GT3 which is a bit rubbish.

Do I care, yes in some cases - esp when it's 122.9p / litre.

Not noticed 1 iota of difference in the car at all, so I'm largely tempted to go back to Sainsburys best.


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