turbo lag affected by the size of the intercooler?

[forced]

Doing any modification to a car is a compromise.

Fitting a bigger intercooler isn't the only way to cool it. It IS the best way for all the salesmen out there as it's nice and simple, looks bling and apeals to all the ricers.

An intercooler thats bigger than stock will generally make more lag than stock. As for HPC coatings, they may be heat resistant but they're not insulators, don't keep heat in or out.

I'm still running stock ICs in mine. Don't have any plans to upgrade either although I've upgraded just about everything else.

As for intercoolers in general, if you're dragracing they might be 100% efficient on the startline but by the time you're half way down the track might be only 50% efficient. Doing a burnout heats it up prematurely because as already said, it's also a heatsink.

Water injection is far, far better but if you've downgraded to an aftermarket speed density type ECU then expect compatibility problems.

As for purpose built drag cars, they generally have a torque curve thats close to zero from idle to 4 K to 5K or thereabouts then it goes straight up. Fitting a proper full length exhaust will give back a lot of the lost torque in the lower RPMs but loose a bit at the top end.

Steve

[toyabusa]

Water injection is far, far better but if you've downgraded to an aftermarket speed density type ECU then expect compatibility problems.

can you please elaborate on the compatibility problems, and why it is a downgrade for those of us that dont know

I'm still running stock ICs in mine. Don't have any plans to upgrade either although I've upgraded just about everything else

do you have a build thread? details?

[kpr]

water injection isnt that great for charge cooling. a decent intercooler will do far better. its good for in cylinder cooling. will let you get away with a bit more boost or more aggressive timing, need bugger all water to replace the cooling of an over rich afr. you'l kill map sensors with water pretty quick, but long as you run up to the sensor and not off the bottom of the manifold, where some water may pool. wont have any issues.

i call bs on the exhaust to big thing. even on n/a, once your past your tuned length basically the extractors and collector, no exhaust is best. that pretty much goes out the window on a turbo car. the more pressure you have after the exhaust wheel the more pressure you have before it. rasing the exhaust manifold pressure is hardly a good thing.

went from a full 2.5" straight through system on my old car (1500 turbo 5efte) to a bit of 3" pipe 1m long at the most. gains everywhere and higher trap speed at the drags.

[Spencer]

yup on a turbo car all the exhaust system does after the turbo is increase gas pressure and temperature for no work. There is a article in race car engineering about turbo exhausts basically best results in spool & power were from short 'megaphone' style exhausts, which can be seen on lots of drag/race cars that permit it (class rules don't need cat converters etc. etc.)

[forced]

[can you please elaborate on the compatibility problems, and why it is a downgrade for those of us that dont know

do you have a build thread? details?

As far as computers goes. I prefer to keep a few things to myself.

There's a very good question to ask any and every ECU salesman out there. Why do so many manufacturers use airflow meters on their turbo cars and use MAP sensors on their top of the line N/A cars?

Until you get an accaptable answer they you're being bullshitted. I haven't had an answer yet but I do have my own opinions which I haven't been proven wrong on yet.

Mitsubishi is the best example. All the Mivec models use MAP sensors for the least possible intake restriction which is a great idea. Mitsi still haven't yet built a MAP sensored turbo car. Obviously there's good reason for it. Look at Toyota. I can't think of a single turbo model with a MAP sensor. How about Nissan? OK Mazda might be a bit different with their turbo rotas. OK so what about the euro turbos?

Build thread? I had an oldschool one on here but deleted it. I've got another on the Mivec forum, different project.

Steve

[forced]

water injection isnt that great for charge cooling. a decent intercooler will do far better. its good for in cylinder cooling. will let you get away with a bit more boost or more aggressive timing, need bugger all water to replace the cooling of an over rich afr. you'l kill map sensors with water pretty quick, but long as you run up to the sensor and not off the bottom of the manifold, where some water may pool. wont have any issues.

i call bs on the exhaust to big thing. even on n/a, once your past your tuned length basically the extractors and collector, no exhaust is best. that pretty much goes out the window on a turbo car. the more pressure you have after the exhaust wheel the more pressure you have before it. rasing the exhaust manifold pressure is hardly a good thing.

went from a full 2.5" straight through system on my old car (1500 turbo 5efte) to a bit of 3" pipe 1m long at the most. gains everywhere and higher trap speed at the drags.

Water is an "anti detonant". With water injection you not only increase timing but reduce AFR and you can use it with no intercooler at all, you won't get knock if done properly.How many tuners in NZ actually recommend WI to customers? Must be bad for business.

As far as the exhaust goes you should be aware that restriction and backpressure are two totally different concepts. If you build a (N/A) motor with no exhaust apart from the manifold then drive it, you'll be aware that the low down torque has virtually disappeared, in fact it probably won't even idle.

Take that one step further and have a short exhaust. low down torque improves because you adding backpressure but also adding a bit of restriction.Drivability still suffers though compared to a proper exhaust.

Take it further again to a full length pipe and you've got far better drivability.

The same applies to turbos but a turbo tends to add backpressure due to the "flywheel effect" If a turbo is sized to give good low down torque then it will boost lowdown torque. If a turbo is sized for top end power then you'll end up with the same as a N/A car once you rip off the exhaust.

You won't loose a great deal at the bottom end but probably enough to get smoked pulling out of a hairpin at Manfield if you forget to change down to 1st gear.

Here's a really good article on WI.

http://www.perrinperformance.com/pages/show/51

Steve

[nothingsfree]

[can you please elaborate on the compatibility problems, and why it is a downgrade for those of us that dont know

do you have a build thread? details?

As far as computers goes. I prefer to keep a few things to myself.

Steve

Its all good keeping it to yourself, but maybe you shouldnt make comments bout it if youre not willing to share your opinions?

Honestly I would like to see your reasoning, always interesting to hear another point of view, especially one outside the square...

[Kelvin]

Look at Toyota. I can't think of a single turbo model with a MAP sensor.

Gen 3 mr2

[Spencer]

Look at Toyota. I can't think of a single turbo model with a MAP sensor.

Um how about a couple of there most famous turbo engines the 1 & 2jzgte

[fuel]

Mitsi Cordias, FWD Sigma turbos, Starion etc have a map sensor in conjunction with an AFM.

[FLAWLES]

Look at Toyota. I can't think of a single turbo model with a MAP sensor.

Um how about a couple of there most famous turbo engines the 1 & 2jzgte

only the twin turbo ones run map dont they diddy?

single turbo 1jz run afm

[kpr]

water injection isnt that great for charge cooling. a decent intercooler will do far better. its good for in cylinder cooling. will let you get away with a bit more boost or more aggressive timing, need bugger all water to replace the cooling of an over rich afr. you'l kill map sensors with water pretty quick, but long as you run up to the sensor and not off the bottom of the manifold, where some water may pool. wont have any issues.

i call bs on the exhaust to big thing. even on n/a, once your past your tuned length basically the extractors and collector, no exhaust is best. that pretty much goes out the window on a turbo car. the more pressure you have after the exhaust wheel the more pressure you have before it. rasing the exhaust manifold pressure is hardly a good thing.

went from a full 2.5" straight through system on my old car (1500 turbo 5efte) to a bit of 3" pipe 1m long at the most. gains everywhere and higher trap speed at the drags.

Water is an "anti detonant". With water injection you not only increase timing but reduce AFR and you can use it with no intercooler at all, you won't get knock if done properly.How many tuners in NZ actually recommend WI to customers? Must be bad for business.

As far as the exhaust goes you should be aware that restriction and backpressure are two totally different concepts. If you build a (N/A) motor with no exhaust apart from the manifold then drive it, you'll be aware that the low down torque has virtually disappeared, in fact it probably won't even idle.

Take that one step further and have a short exhaust. low down torque improves because you adding backpressure but also adding a bit of restriction.Drivability still suffers though compared to a proper exhaust.

Take it further again to a full length pipe and you've got far better drivability.

The same applies to turbos but a turbo tends to add backpressure due to the "flywheel effect" If a turbo is sized to give good low down torque then it will boost lowdown torque. If a turbo is sized for top end power then you'll end up with the same as a N/A car once you rip off the exhaust.

You won't loose a great deal at the bottom end but probably enough to get smoked pulling out of a hairpin at Manfield if you forget to change down to 1st gear.

Here's a really good article on WI.

http://www.perrinperformance.com/pages/show/51

Steve

plenty of turbo toyota's run map sensors. the 4efte from starlets is another example.

yes water injection is good, but is another thing to go wrong. if your relying on it to keep the engine from detonating. run out of water, pump stuffs up, block jet etc. good by engine. i know there is some good attempts at fail safe systems out there, but they come at a pretty big price. have ran it before, injecting into the intercooler piping, then moved onto a port injection setup. worked well for what i wanted to do. but wouldn't run it in all situations.

from my small amount of experience with n/a setups. how you have explained the exhaust "back pressure" and full length systems, is the total opposite of what i have found. i gained near 15kw in the lower rpm area by switching from a 2" to 2.5" exhaust. top end was hardly effected. even more is to be had with no exhaust after the extractors and collector. as it has a lean spot. yes it would not run properly with no exhaust, but only because it was so lean.

maybe ive came across something a little different here, but im sticking with back pressure is bs.

ive already stated what ive found with turbo stuff. its up there ^

[H05TYL]

back pressure is bullsh1t, fullstop, the end.

reflected pressure waves are worth looking into though.

[forced]

Backpressure is a dynamic measurement It's created when a valve closes.

You're getting mixed up with restriction just like everyone else does.

Backpressure is the equivalent to back EMF in electrical theory and restriction in a pipe is equivalent to resistance as in ohms.

Backpressure has the potential to cause backflow.

Backflow is when the high pressure end becomes the low pressure end and you get flow into the pipe instead of out of the pipe.

Anyone who's had a leak in an exhaust front pipe would have noticed that you get more sucking than blowing. That backflow reduces the backpressure and kills low down torque.

A term often used when thinking about back EMF in electrical theory is the "flywheel effect"

A turbo is a flywheel and when you suddenly close the throttle the turbo creates "backpresssure" at the intake side which escapes out of the BOV.

There you go, food for thought.

Getting way OT again.

Steve