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The mkiv Supra Owners Club

Standing start- 450 bhp auto "v" five speed manual?


herbiemercman

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Hi Noz, Your on it and i enjoy your reasoning and the info., which you have from "hands on" experience. The cost was not an issue on the purchase spec, i just wanted the manual gear box, my knowledge of performance was even worse than it is currently, so all the performance info was irrelevant at the time.

 

Anyway Noz, I like the looks and performance of my car, it also has what money cannot buy, which is the memories it has for me, and i hope that will keep building, especially in the current circumstances. One thing i would love you doing for me, is trying to give your oinion on how much torque and BHP could i have lost from increasing the cylinder head gasket thickness from 0.6mm to 1.3mm? I may be suffering the "plasebo effect", but the current performance is as good as it has ever been. ? Finally for me, i would never class the Supra as a "Tourer", it is an insult to the breed, no one would class the E-Type as a "Tourer", i do not get it, and i never will. ! Herbie.

 

The Supra was classed as a tourer by Toyota themselves. It's what they built the car to do. You say yourself, that the car feels very stable at the "silly" speeds and getting up to those speeds is also fairly effortless. That, right there, is what a tourer does. An E-type is also a grand-tourer as stated by Jaguar themselves with the convertable being a roadster.

 

Any car with GT in the title is the same, including extra letters. GTI, GT-R, GTB etc.

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The Supra was classed as a tourer by Toyota themselves. It's what they built the car to do. You say yourself, that the car feels very stable at the "silly" speeds and getting up to those speeds is also fairly effortless. That, right there, is what a tourer does. An E-type is also a grand-tourer as stated by Jaguar themselves with the convertable being a roadster.

 

Any car with GT in the title is the same, including extra letters. GTI, GT-R, GTB etc.

 

Steve mate, is this guy on crack or something?! Or is he on a wind up you reckon?! lol

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Steve mate, is this guy on crack or something?! Or is he on a wind up you reckon?! lol

 

Hi Burna, This has been a good thread and well supported, i don't know why you have brought crack into it? and i can see the different opinions being exchanged, and input from yourself, but where do you see the wind up? I can see that Style is correct that the Supra was put out by Toyota as a tourer, i am just saying that for most people it is seen as a sports car, or sports coupe due to its looks and performance etc. Herbie.

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You gave your opinions and i gave mine, no intention at my end for a wind up, i cannot see why Burna stepped in as he did, that could have been more of a wind up for me. Don't give up.lol

 

Just because you don't see it, doesn't mean others don't ;)

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Hi Noz, Your on it and i enjoy your reasoning and the info., which you have from "hands on" experience. The cost was not an issue on the purchase spec, i just wanted the manual gear box, my knowledge of performance was even worse than it is currently, so all the performance info was irrelevant at the time.

 

Anyway Noz, I like the looks and performance of my car, it also has what money cannot buy, which is the memories it has for me, and i hope that will keep building, especially in the current circumstances. One thing i would love you doing for me, is trying to give your oinion on how much torque and BHP could i have lost from increasing the cylinder head gasket thickness from 0.6mm to 1.3mm? I may be suffering the "placebo effect", but the current performance is as good as it has ever been. ? Finally, for me, i would never class the Supra as a "Tourer", it is an insult to the breed, no one would class the E-Type as a "Tourer", i do not get it, and i never will. ! Herbie.

 

As Style mentioned. Toyota did indeed design and define the car as a tourer.

 

However, that doesn't mean it's got to be defined as a hauling sluggish motor vehicle.

 

The fan base has turned the car into something much more. But by definition, it's a GT, touring 3 door. However much you stomp lol.

 

Regarding the torque difference, NA is 10.0:1. Various sources to hand state 9.2:1 is an NA engine with a TT headgasket.

 

I'd just like to add that TT owners don't complain about the low-end drop in performance, and they have a 8.5:1 ratio so will see worst low-end response.

 

There is some data on thermal efficiency when considering engine engines with Otto cycle. https://www.ohio.edu/mechanical/thermo/Intro/Chapt.1_6/Chapter3d.html

 

Feel free to research

 

To generalise, you can find data online that indicates a rough amount of power loss for the lower compression ratio. Remember, however, this value is below 3.8k before the turbo spools. Once that turbo begins to introduce a pressure change you are above and beyond the NA.

 

I've spent time looking into this, understanding the maths and I believe strongly there's going to be a 5-10% loss in torque at the most, in sub 4k rpm values. Looking at the stock dyno curve, that's maybe 20 ft lb.

 

image

 

Honestly. If this bothers you, buy a torqamp electric charger pre-turbo. Gives 200 ft lb at sub 4k rpm. I'm considering it for lower end power. But not, to replace what my compression ratio has lost. That's really peanuts.

 

I find it highly unlikely you'll be able to notice it. Your lower end power felt as a percentage, more responsive. It was around 50-60% of your total power. Now, its 30-40% if not less. So that part of your power band is going to feel less by comparison.

 

The car will, of course, feel slower lower down, because the overall performance power band is not the same distribution of power it once was. It's been increased at the top end not the bottom.

 

You need to honestly get over this compression stuff mate. It's not an issue. Wanting lower down performance is a separate issue that we all want, but chasing the compression ratio you have lost isn't the way to get this. You haven't lost anything worth worrying about low end.

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As Style mentioned. Toyota did indeed design and define the car as a tourer.

 

However, that doesn't mean it's got to be defined as a hauling sluggish motor vehicle.

 

The fan base has turned the car into something much more. But by definition, it's a GT, touring 3 door. However much you stomp lol.

 

Regarding the torque difference, NA is 10.0:1. Various sources to hand state 9.2:1 is an NA engine with a TT headgasket.

 

I'd just like to add that TT owners don't complain about the low-end drop in performance, and they have a 8.5:1 ratio so will see worst low-end response.

 

There is some data on thermal efficiency when considering engine engines with Otto cycle. https://www.ohio.edu/mechanical/thermo/Intro/Chapt.1_6/Chapter3d.html

 

Feel free to research

 

To generalise, you can find data online that indicates a rough amount of power loss for the lower compression ratio. Remember, however, this value is below 3.8k before the turbo spools. Once that turbo begins to introduce a pressure change you are above and beyond the NA.

 

I've spent time looking into this, understanding the maths and I believe strongly there's going to be a 5-10% loss in torque at the most, in sub 4k rpm values. Looking at the stock dyno curve, that's maybe 20 ft lb.

 

https://lh3.googleusercontent.com/proxy/vN8EM5b3EDWFBoBZ-XqaeRmw7DxkM4tuEZqHBLujyxu3taeoriCW8h1TJkdrwpnsdtkPpKNwtq_OLSBEHprCbBrMyZ4qzQJaN6alLdWXig

 

Honestly. If this bothers you, buy a torqamp electric charger pre-turbo. Gives 200 ft lb at sub 4k rpm. I'm considering it for lower end power. But not, to replace what my compression ratio has lost. That's really peanuts.

 

I find it highly unlikely you'll be able to notice it. Your lower end power felt as a percentage, more responsive. It was around 50-60% of your total power. Now, its 30-40% if not less. So that part of your power band is going to feel less by comparison.

 

The car will, of course, feel slower lower down, because the overall performance power band is not the same distribution of power it once was. It's been increased at the top end not the bottom.

 

You need to honestly get over this compression stuff mate. It's not an issue. Wanting lower down performance is a separate issue that we all want, but chasing the compression ratio you have lost isn't the way to get this. You haven't lost anything worth worrying about low end.

 

Thanks a lot Noz, Good info, just what i need at the moment.

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I'd have thought there would be a power loss throughout the rev range and not just at the bottom? Only reason being the car hasn't been remapped since the headgasket was changed. So same amount of air and fuel going in at 9.2:1 as before at 10:1 resulting in a smaller power stroke?

 

A remap with more boost and you're laughing. But I think it's still on stock pump/injectors.

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I'd have thought there would be a power loss throughout the rev range and not just at the bottom? Only reason being the car hasn't been remapped since the headgasket was changed. So same amount of air and fuel going in at 9.2:1 as before at 10:1 resulting in a smaller power stroke?

 

A remap with more boost and you're laughing. But I think it's still on stock pump/injectors.

 

Correlating NA power vs NA-t power. Boost vs NA. Boosting the NA OEM ratio would, of course, be different. But we are talking from a before vs after situation mate, rather than what's the potential best performance situation.

 

- - - Updated - - -

 

I never heard of torqamp system, may look in to that.

But do know with nos you can fully customise it and have different shots at different times and can control size and length of each shot for maximum results

 

It's the way forward, I've always wanted pre-spool nitrous!

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and 1st gear makes the car an animal and makes all the difference, and being as it's such a long gear you can use it a hell of a lot, like when entering and exiting islands etc...

 

 

I drove mine to work yesterday and enjoyed the second gear transition around 45-50mph I think it is, but actually noticed waiting for that, so I have perhaps been a bit lazy and can see how 1st would be more useful when 'on it'.

 

I tend to use mine on the odd work commute and on a particular flowing road that has few low speed sections, but I'm going to try and use it more..........I'm sure it'll highlight my other laziness of not fitting a LSD yet!

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Correlating NA power vs NA-t power. Boost vs NA. Boosting the NA OEM ratio would, of course, be different. But we are talking from a before vs after situation mate, rather than what's the potential best performance situation.

 

I think that's what Herbie was asking about mate.

 

He was stock engined NA-T and then blew the headgasket, fitted a TT one and never got the car re-mapped so a few people mentioned he'd be down on power. So I thought he was asking about 10:1 NA-T power vs 9.2:1 NA-T power on the exact same map. That was my thinking of what was asked at least :D

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I drove mine to work yesterday and enjoyed the second gear transition around 45-50mph I think it is, but actually noticed waiting for that, so I have perhaps been a bit lazy and can see how 1st would be more useful when 'on it'.

 

I tend to use mine on the odd work commute and on a particular flowing road that has few low speed sections, but I'm going to try and use it more..........I'm sure it'll highlight my other laziness of not fitting a LSD yet!

 

You are thinking correctly, it takes away waiting for that the second gear second turbo transition. It keeps the car on boost, and like I said 1st gear is an animal, but is such a long gear it's more usable than a manual car. And yeah be careful if you haven't got an LSD! lol

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As Style mentioned. Toyota did indeed design and define the car as a tourer.

 

However, that doesn't mean it's got to be defined as a hauling sluggish motor vehicle.

 

The fan base has turned the car into something much more. But by definition, it's a GT, touring 3 door. However much you stomp lol.

 

Regarding the torque difference, NA is 10.0:1. Various sources to hand state 9.2:1 is an NA engine with a TT headgasket.

 

I'd just like to add that TT owners don't complain about the low-end drop in performance, and they have a 8.5:1 ratio so will see worst low-end response.

 

There is some data on thermal efficiency when considering engine engines with Otto cycle. https://www.ohio.edu/mechanical/thermo/Intro/Chapt.1_6/Chapter3d.html

 

Feel free to research

 

To generalise, you can find data online that indicates a rough amount of power loss for the lower compression ratio. Remember, however, this value is below 3.8k before the turbo spools. Once that turbo begins to introduce a pressure change you are above and beyond the NA.

 

I've spent time looking into this, understanding the maths and I believe strongly there's going to be a 5-10% loss in torque at the most, in sub 4k rpm values. Looking at the stock dyno curve, that's maybe 20 ft lb.

 

https://jza80.mkivsupra.net/imports/2020/04/138.jpg

 

Honestly. If this bothers you, buy a torqamp electric charger pre-turbo. Gives 200 ft lb at sub 4k rpm. I'm considering it for lower end power. But not, to replace what my compression ratio has lost. That's really peanuts.

 

I find it highly unlikely you'll be able to notice it. Your lower end power felt as a percentage, more responsive. It was around 50-60% of your total power. Now, its 30-40% if not less. So that part of your power band is going to feel less by comparison.

 

The car will, of course, feel slower lower down, because the overall performance power band is not the same distribution of power it once was. It's been increased at the top end not the bottom.

 

You need to honestly get over this compression stuff mate. It's not an issue. Wanting lower down performance is a separate issue that we all want, but chasing the compression ratio you have lost isn't the way to get this. You haven't lost anything worth worrying about low end.

 

Thanks Noz, Good info which i enjoyed reading, i will let the CR drift away now and think more about the more robust gasket's performance. Herbie.

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