Dynod BUT couldnt get traction even in 5th so only made 404bhp lol
- Thread starter Dan3SGTE
- Start date
Dan3SGTE
Member +
Im going to post my AFR graph and see what you think
Texx
Super Moderator
Looking at the dyno graph above and assuming the turbo did maintain full boost to 7000rpm, I would take a guess and say you would have seen a HP reading of around 450 if the tyres didn't lose traction.
Texx
Super Moderator
According to the SW20 Turbo manual, base fuel pressure is somewhere around 33-38psi.
So add your 27psi peak boost pressure to that will give you a full boost maximum fuel rail pressure of 65psi. Again going by the above flow graph we can suggest the Walbro should be able to maintain a flow rate of 220LPH at 65psi. 220LPH should be enough to produce at least 450HP before becoming a limiting factor.
gorganl2000
Lifer
congrats on the power made so far
spuddy
Ulster Area Rep.
Nice work Dan!
I've had a couple of them Walbros shit themselves and when mapping all that happens is the mapper tells the ecu to add more and more fuel which in the end gives the impression of the injectors being maxed.
I'd say its the pump is on the way out rather than not up for the job.
I've had a couple of them Walbros shit themselves and when mapping all that happens is the mapper tells the ecu to add more and more fuel which in the end gives the impression of the injectors being maxed.
I'd say its the pump is on the way out rather than not up for the job.
Dan3SGTE
Member +
@TEXX appreciated all that info there mate, things are making a little more sense now.
@Spuddy, cheers bro!
Again thats some handy info as that seems even more now aiming at this stupid pump! I feel i need 1 more dyno run on another dyno with traction and then if im making anything around say 440 at 1.85bar then i know we are pretty good... If not then a new pump and more boost! The turbo is good for 2.2bar anyway.. This turbo makes up to 520-530bhp so should be good enough.. Just need the right amount of fuel to make the power!
Cheers everyone, appreciate all the help in diagnosing!
@Spuddy, cheers bro!
Again thats some handy info as that seems even more now aiming at this stupid pump! I feel i need 1 more dyno run on another dyno with traction and then if im making anything around say 440 at 1.85bar then i know we are pretty good... If not then a new pump and more boost! The turbo is good for 2.2bar anyway.. This turbo makes up to 520-530bhp so should be good enough.. Just need the right amount of fuel to make the power!
Cheers everyone, appreciate all the help in diagnosing!
spuddy
Ulster Area Rep.
Keep at it, you'll get your goal
FWD on dynos is annoying when it comes to grip, we had to use some slicks on mine lol.
Hub dyno is the way to go. What CV cages are u running? Stock or the uprated ones? MR2 ones can be a weak point, I'm sure you know that but just incase, would want ya getting stuck some where
FWD on dynos is annoying when it comes to grip, we had to use some slicks on mine lol.
Hub dyno is the way to go. What CV cages are u running? Stock or the uprated ones? MR2 ones can be a weak point, I'm sure you know that but just incase, would want ya getting stuck some where
Dan3SGTE
Member +
Keep at it, you'll get your goal
FWD on dynos is annoying when it comes to grip, we had to use some slicks on mine lol.
Hub dyno is the way to go. What CV cages are u running? Stock or the uprated ones? MR2 ones can be a weak point, I'm sure you know that but just incase, would want ya getting stuck some where
That i dont actually remember is was a long time ago now.. Lets hope they dont break eh, i do have RAC cover so not the end of the world lol! Yeah thats the problem you start hitting high number on these small light hatches and they just spin.
The problem is if i get the pump now and get it mapped again thats gona cost me about £400 all in including fuel etc which at the moment i really havent got. And Adrian has said he thinks that everything is fine and the graph was due to wheel spin and/or because it was sitting on the dyno not getting enough cooling the car pulls out some ignition and lowers boost levels slightly and on road will be making more power..
Dan3SGTE
Member +
Thanks paul! To be honest this result is with wheel spin anyway mate so im pretty confident its going to be 450ish.. I'll post up new results on a hub dyno with the WHP reading instead. There is more power to be had in the car whilst still maintaining grip at least in 4th and 5th... 3rd gear needs more traction on most roads but i will be upgrading from 195 to 215 and to a 16 inch wheel increasing gear ratios.. So traction should be alot better then anyway...
Oh yeah as it is it has more then enough power to do 10's up the quarter, but not really a quarter mile type of guy but i will have a few goes soon for some fun...
Texx
Super Moderator
A wider tyre won't provide any additional traction unless your intending to use a tyre with a softer compound than the 195 or the 195 is overheating (which is unlikely). If it's a larger contact patch that your looking for, the only way to achieve it is by either reducing the tyre pressure or increasing the weight of the car.
Dan3SGTE
Member +
Sorry texx i dont understand why you will not get a wider contact patch with a wider tire on the correct tire to wheel width combo? So what your saying is if i put on something huge like a 255 for instant would that still not give more of a contact patch? Im a little confused on this.
PS.. Ive upgraded tire sizes on several cars in the past and definitely have gained traction on the same pressures and compound.
Texx
Super Moderator
The size of the contact patch is dictated by the air pressure in the tyre and the weight of the car acting on it. The width of a tyre dictates the operating temperature, basically because a wider tyre has more rubber than a narrower tyre it can dissipate heat more affectively.
I'll try and explain a little better:
Lets take a guess and suggest the front end of a Starlet weighs 550KG, 550KG is approx 1212lbs, so we'll round that down to 1200lbs just to simplify this explanation. OK, so 1200lbs on the front end split between 2 tyres gives us a weight of 600lbs on each tyre.
Next we need our tyre pressure, again trying not to over complicate things we'll pick 30psi as our front tyre pressure. So what does 30psi represent? simply the air pressure in the tyre can support 30 pounds of weight per square inch of surface area. This means that for every 30 pounds of weight sat on the tyre, the contact patch on the ground will increase by 1 square inch.
A simple calculation:
weight / tyre pressure = area of contact patch
i.e. 600lbs / 30psi = 20 square inches
That tells us that both of the tyres on the front end of our Starlet when inflated to 30psi will have a contact patch of 20 square inches. Notice how tyre height or width does not come into this calculation. It doesn't matter what size tyre you fit, the contact patch will always remain the same unless either the weight sat on the tyre is increased/reduced or the air pressure in the tyre is increased/reduced.
By using my awesome Paint skills and without being specific with tyre widths, the difference in the contact patch of a narrow tyre vs a wide tyre fitted to our fictitious Starlet and inflated to the same pressure would look something like this:
(each square represents 1 square inch)
The area of the contact patch of each tyre is the same, only the shape of the contact patch changes.
The amount of 'grip' a tyre can generate is dictated by the coefficient of friction of the rubber compound it's made from. The force of friction created between the tyre and the road surface generates heat, if the tyre is too narrow (i.e. doesn't have enough rubber to dissipate the heat generated) it'll overheat, if the tyre is too wide the tyre compound won't reach it's optimum operating temperature.
Take F1 cars for example, they use wide tyres. To get the most out of these wide tyres they need to push hard through the corners and accelerate fast down the straight to keep them up to temperature. When the safety car comes out and everyone has to slow down, you see the drivers weaving from one side of the track to the other, if they didn't do this the tyre compound would cool down and it's 'coefficient of friction' would drop. A F1 car entering a corner at high speed with cold tyres will end up in the barrier. If the F1 cars were fitted with narrow tyres to prevent this happening, after a hard lap the tyre would overheat and disintegrate. So there is a element of tyre width tuning going on to give the best tyre temperature control for 'normal' race conditions.
So in essence, the tyre compound and the actual area of the tread pattern in contact with the ground dictates the level of grip achieved.
I'll try and explain a little better:
Lets take a guess and suggest the front end of a Starlet weighs 550KG, 550KG is approx 1212lbs, so we'll round that down to 1200lbs just to simplify this explanation. OK, so 1200lbs on the front end split between 2 tyres gives us a weight of 600lbs on each tyre.
Next we need our tyre pressure, again trying not to over complicate things we'll pick 30psi as our front tyre pressure. So what does 30psi represent? simply the air pressure in the tyre can support 30 pounds of weight per square inch of surface area. This means that for every 30 pounds of weight sat on the tyre, the contact patch on the ground will increase by 1 square inch.
A simple calculation:
weight / tyre pressure = area of contact patch
i.e. 600lbs / 30psi = 20 square inches
That tells us that both of the tyres on the front end of our Starlet when inflated to 30psi will have a contact patch of 20 square inches. Notice how tyre height or width does not come into this calculation. It doesn't matter what size tyre you fit, the contact patch will always remain the same unless either the weight sat on the tyre is increased/reduced or the air pressure in the tyre is increased/reduced.
By using my awesome Paint skills and without being specific with tyre widths, the difference in the contact patch of a narrow tyre vs a wide tyre fitted to our fictitious Starlet and inflated to the same pressure would look something like this:
(each square represents 1 square inch)
The area of the contact patch of each tyre is the same, only the shape of the contact patch changes.
The amount of 'grip' a tyre can generate is dictated by the coefficient of friction of the rubber compound it's made from. The force of friction created between the tyre and the road surface generates heat, if the tyre is too narrow (i.e. doesn't have enough rubber to dissipate the heat generated) it'll overheat, if the tyre is too wide the tyre compound won't reach it's optimum operating temperature.
Take F1 cars for example, they use wide tyres. To get the most out of these wide tyres they need to push hard through the corners and accelerate fast down the straight to keep them up to temperature. When the safety car comes out and everyone has to slow down, you see the drivers weaving from one side of the track to the other, if they didn't do this the tyre compound would cool down and it's 'coefficient of friction' would drop. A F1 car entering a corner at high speed with cold tyres will end up in the barrier. If the F1 cars were fitted with narrow tyres to prevent this happening, after a hard lap the tyre would overheat and disintegrate. So there is a element of tyre width tuning going on to give the best tyre temperature control for 'normal' race conditions.
So in essence, the tyre compound and the actual area of the tread pattern in contact with the ground dictates the level of grip achieved.
Texx
Super Moderator
Thinking a wider tyre puts more rubber on the road is an easy misconception to make. More often than not a larger/wider tyre just adds more unnecessary unsprung weight to the car.
Dan3SGTE
Member +
Guys after doing some research maybe this is something to consider. Have a read through this and see what you think. I dont think its as simple as what your saying Texx. Seems like there is alot more to it.
And dont get me wrong i really value your views here im just throwing this out there, Im no expert. And your obviously very knowledgeable.
http://www.performancesimulations.com/fact-or-fiction-tires-1.htm
And dont get me wrong i really value your views here im just throwing this out there, Im no expert. And your obviously very knowledgeable.
http://www.performancesimulations.com/fact-or-fiction-tires-1.htm
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