Jump to content
The mkiv Supra Owners Club

more power


grahamc
 Share

Recommended Posts

front seats ditched for sparco fixed back ones

rear seats out, including rear seat belts

all boot equipment, including space saver out

all sound equipment out - put some back in, but never wired it up so that needs to come out

electric mirrors binned for apr carbon ones

 

plan for the winter is

to strip down the dash completely over the winter

remove the carpet (replace with something else...??)

move battery to behind seat

remove the sound deadening

 

also want to try my hand at making some fibreglass/carbon fibre panels to replace parts of the dash, looking at the link display or some sort of digital dash to do the job.

 

Also, you could go on a diet? best way of shedding weight from the car! :p

Link to comment
Share on other sites

  • Replies 87
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Also, you could go on a diet? best way of shedding weight from the car! :p

 

I plan to!! As soon as I move, I am starting to cycle to work... 5.5 miles of hills!! :blink: not lookng forward to that first week or 2 :D

 

BTW, what boost are you running Graham?

 

1.1 bar with the controller turned off

1.4 bar the max on the controller

 

Ryan and I will be looking at some sort of progressive boost setup!

Link to comment
Share on other sites

I would not do it by it self, other parts are needed, boost controller, fueling, cooling, etc

 

I got the hybrids off a fellow member who was going single with his supra :D good deal, since I knew my turbos were shagged

 

cheers mate - so not a £300 quick fix to get loads more bhp then? lol

 

;)

Link to comment
Share on other sites

I plan to!! As soon as I move, I am starting to cycle to work... 5.5 miles of hills!! :blink: not lookng forward to that first week or 2 :D

 

1.1 bar with the controller turned off

1.4 bar the max on the controller

 

Ryan and I will be looking at some sort of progressive boost setup!

 

Sounds like what im going to be running on my set up aside from ill be boosting 1.2 bar normal driving i think.

 

The only difference between our set ups are the CAMs which i dont have, not sure if they make a difference though? what would they assist in Graham? Im hopeing that my re-built engine and new hybrids will make at least what yours is putting out. 450 is a great figure

Link to comment
Share on other sites

What a horrible moulding, the inside of the shell is disgusting.. My man did a much nicer job as a one off, and he isn't gearing up to do a run of them. How much are these Seibon ones? Doesn't seem to give the weight, either, which is the whole point of the things!

 

Does it really matter what the inside looks like?! :search:

Link to comment
Share on other sites

What a horrible moulding, the inside of the shell is disgusting.. My man did a much nicer job as a one off, and he isn't gearing up to do a run of them. How much are these Seibon ones? Doesn't seem to give the weight, either, which is the whole point of the things!

 

i know little about them tbh i just remembered the suppliers name.

Link to comment
Share on other sites

Sounds like what im going to be running on my set up aside from ill be boosting 1.2 bar normal driving i think.

 

The only difference between our set ups are the CAMs which i dont have, not sure if they make a difference though? what would they assist in Graham? Im hopeing that my re-built engine and new hybrids will make at least what yours is putting out. 450 is a great figure

 

So you have fueling and ecu? Which did you go for? mid range is what the cams were for... where I can feel a difference :search:

 

C16 race fuel ;)

nice ;)

 

how many litres is 5 gallons? is that enough for a mapping session?

Link to comment
Share on other sites

You can lean out more on C15.. Maybe get away with running 12.5.... Hence the more HP... More Octane Less Knocksum.... To how much you require is how many runs the mapper does.... As you know our cars on boost love fuel so like alex says maybe arround the 20 litres mark for a good few consecitive runs

 

Correct, but doesn't the higher octane also burn slower and so allow more advance ?

Link to comment
Share on other sites

From an EFI web site:

 

In turbocharged engines there is a fine balancing act when it comes to making a lot of power on low octane fuel. In most cases, ignition timing must be retarded as the boost pressure rises above a critical point and finally there reaches a further point where the engine simply loses power. If the timing was not retarded with increasing boost, destructive preignition or detonation would occur. Normal combustion is characterized by smooth, even burning of the fuel/air mixture. Detonation is characterized by rapid, uncontrolled temperature and pressure rises more closely akin to an explosion. It's effects are similar to taking a hammer to the top of your pistons.

 

Most engines make maximum power when peak cylinder pressures are obtained with the crankshaft around 15 degrees after TDC. Experimentation with increasing boost and decreasing timing basically alters where and how much force is produced on the crankshaft. Severely retarded timing causes high exhaust gas temperatures which can lead to preignition and exhaust valve and turbo damage.

 

We have a hypothetical engine. It's a 2.0L, 4 valve per cylinder, 4 cylinder type with a 9.0 to 1 compression ratio and it's turbocharged. On the dyno, the motor puts out 200hp at 4psi boost with the timing at the stock setting of 35 degrees on 92 octane pump gas with an air/fuel ratio of 14 to 1. We retard the timing to 30 degrees and can now run 7psi and make 225hp before detonation occurs. Now we richen the mixture to 12 to 1 AFR and find we can get 8psi and 235 hp before detonation occurs. The last thing we can consider is to lower the compression ratio to 7 to1. Back on the dyno, we can now run 10psi with 33 degrees of timing with an AFR of 12 to 1 and we get 270 hp on the best pull.

 

We decide to do a test with our 9 to 1 compression ratio using some 118 octane leaded race gas. The best pull is 490 hp with 35 degrees of timing at 21 psi. On the 7 to 1 engine, we manage 560 hp with 35 degrees of timing at 25psi. To get totally stupid, we fit some larger injectors and remap the EFI system for126 octane methanol. At 30psi we get 700hp with 35 degrees of timing!

 

While all of these figures are hypothetical, they are very representative of the gains to be had using high octane fuel. Simply by changing fuel we took the 7 to 1 engine from 270 to 700 hp.

 

From all of the changes made, we can deduce the effect certain changes on hp;

 

Retarding the ignition timing allows slightly more boost to be run and gain of 12.5%.

 

Richening the mixture allows slightly more boost to be run for a small hp gain however, past about 11.5 to 1 AFR most engines will start to lose power and even encounter rich misfire.

 

Lowering the compression ratio allows more boost to be run with less retard for a substantial hp gain.

 

Increasing the octane rating of the fuel has a massive effect on maximum obtainable hp.

 

We have seen that there are limits on what can be done running pump gas on an engine with a relatively high compression ratio. High compression engines are therefore poor candidates for high boost pressures on pump fuel. On high octane fuels, the compression ratio becomes relatively unimportant. Ultimate hp levels on high octane fuel are mainly determined by the physical strength of the engine. This was clearly demonstrated in the turbo Formula 1 era of a decade ago where 1.5L engines were producing up to 1100 hp at 60psi on a witches brew of aromatics. Most fully prepared street engines of this displacement would have trouble producing half of this power for a short time, even with many racing parts fitted.

 

Most factory turbocharged engines rely on a mix of relatively low compression ratios, mild boost and a dose of ignition retard under boost to avoid detonation. Power outputs on these engines are not stellar but these motors can usually be seriously thrashed without damage. Trying to exceed the factory outputs by any appreciable margins without higher octane fuel usually results in some type of engine failure. Remember, the factory spent many millions engineering a reasonable compromise in power, emissions, fuel economy and reliability for the readily available pump fuel. Despite what many people think, they probably don't know as much about this topic as the engineers do.

 

One last method of increasing power on turbo engines running on low octane fuel is water injection. This method was evaluated scientifically by H. Ricardo in the 1930s on a dyno and showed considerable promise. He was able to double power output on the same fuel with the aid of water injection.

 

First widespread use of water injection was in WW2 on supercharged and turbocharged aircraft engines for takeoff and emergency power increases. The water was usually mixed with 50% methanol and enough was on hand for 10-20 minutes use. Water/methanol injection was widely used on the mighty turbocompound engines of the '50s and '60s before the advent of the jet engine. In the automotive world, it was used in the '70s and '80s when turbos suddenly became cool again and where EFI and computer controlled ignitions were still a bit crude. Some Formula 1 teams experimented with water injection for qualifying with success until banned.

 

My personal experience with water injection is considerable. I had several turbo cars fitted with it. One 2.2 liter Celica with a Rajay turbo, Weber carb and no intercooler or internal engine mods ran 13.3 at 103 on street rubber on pump gas back in 1987. This was accomplished at 15psi. With the water injection switched off, I could only run about 5 psi before the engine started to ping. I think you might see water injection controlled by microchips, catch on again in the coming years on aftermarket street turbo installations. It works.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.