Forgive my ignorance but I must know....

[concealer404]

Is that KL-specific info?

[SBPGT]

No, Ford GT.

Maybe the Probe should be called the Mazda GT?

[concealer404]

So that should just be viewed as a rule of thumb, then, with some pretty common exceptions.

[pile_of_rd1]

^ I just wanna know where your "experience" comes from.

[concealer404]

My boosted BP that's currently detonation limited due to its stock compression ratio of 9.5:1. It would spool faster and have a wider powerband if i could reach the proper amount of timing.

The kind of timing that's able to be run with an 8.6:1 compression motor. To that end, i'd see a better power band, faster spool, and even make more power on the same amount of boost even though it's a lower compression motor. Simply because of the amount of timing i'd be able to run.

Talking pump gas, of course. Moving to E85 would let me run all the timing i'd need.


Full disclosure: I have no idea whatsoever if this applies to the KL, or if it does, exactly what compression you become detonation limited on a KL. I'd also suspect that nobody else does, either. This IS pretty well documented on Miataturbo, huge in depth discussions, dozens and dozens of dynos, timing maps, etc etc etc...

I'm simply saying it's potentially something to consider, that's all. I don't know HOW you'd be able to consider it considering the relative lack of data on this motor, but if the info is out there somewhere....

[mac1]

BIte me

Lower compression = less efficient

With all supporting mods being the same, even the tune, all i'm saying is.........

stock KLDE 9.2:1 c/r 16psi made 340hp and could get past a 480hp Terminator
vs.
Vitara 7.7:1 c/r 20psi ???hp could keep up with 670hp Terminator

That's just 4psi more and 1 year after it was last dyno'd still running all the same parts and piston rings were on their 3rd block.
Take all your theories and leave them at the door, let the ones who have actually been there speak.

[blac_shine007]

Lower compression = less efficient



Thanks for quoting me. But that was just a basic generalized example. Turning your engine into a slug to run more boost is not the way to go. Lower compression may be safer, but you'll lose gas mileage, throttle response, and increase turbo lag.

Here is some more info from another site, from someone who builds race motors...

----------------------------

Specifically about the turbo engine, the turbine is spun by the volume and velocity of air forced through the turbine. A lower compression engine just by nature makes less cylinder pressure thus less BANG when it fires. So the turbo is slower to respond and ultimately cannot make as much potential boost. A case in point will be the voice of Chip Beck when he gets his car returned. I spoke to the tuner and he told me that it was the smoothest GT he had ever tuned on the dyno (balanced cams) and the boost came in instantly ( changed cam timing to increase cylinder pressure). As some on here have experienced with their turbo cars the lag is slow to make power. Now if you can spool it up 1000 rpms faster then the gain in power in that window can be enormous. Right behind that is how rpm and shift point come into play. A typical car shifted at 7000 rpms will enter the next gear and have some lag. An engine that we build will drop in the next gear and lag will be much less if any under the same conditions.

So cylinder pressure and valve control is more important on a turbo application above all others. Another critical link about valvetrain stability particular to turbo cars is charge contamination. Obviously there is backpressure in the exhaust at all times under boost. If the exhaust valve bounces and lets spent gases back into the cylinder then the intake charge of fresh air is contaminated and its oxygen content reduced. No oxygen = no power.

Some of the above weak turbo response is cured by using smaller (more restriction) exhaust housings. Less power potential again. So for what we do that doesn't work. Any type of exhaust pressure just by nature will cause some form of reversion particularly in high boost engines. Usually we will raise the compression, move the cams and run a larger exhaust housing. We have faster response, more efficient engine that requires less boost to meet the customers power requirement. Win all the way around.

A typical GT 8.5 to 1 engine will have 160 lbs of cranking compression. Our typical 10 to 1 engine will have 200 psi and our typical 12 to 1 engine will be around 260 psi. It is always difficult to talk our customers into higher compression stuff. Largely I am sure from their past experiences or fear. The engine is going to detonate typically at "X" cylinder pressure regardless of how you get there. The difference being that the higher compression is always more efficient and will always yield more power at the same threshold of detonation. The low compression engine will always require more timing as well. The high compression stuff typically needs 10 degrees less timing so the result is more force is exerted on the crank in a forward motion and less is consumed trying to stop the crank before TDC. The end result shows more power on the dyno and the car will accelerate faster. Also it does NOT require more fuel, it simply produces more power with the fuel it has. We have had brake specific numbers as low as .30 and BMEP above 550 on the dyno with our high compression turbo engines. Can't even come close to that with low compression.

Hope this helps

John

-------------------

Nice find and great info.

With all supporting mods being the same, even the tune, all i'm saying is.........

stock KLDE 9.2:1 c/r 16psi made 340hp and could get past a 480hp Terminator
vs.
Vitara 7.7:1 c/r 20psi ???hp could keep up with 670hp Terminator

That's just 4psi more and 1 year after it was last dyno'd still running all the same parts and piston rings were on their 3rd block.
Take all your theories and leave them at the door, let the ones who have actually been there speak.

I'm interested to see your dyno numbers. What are you revving it to?

[mac1]

6900 because I dont like to abuse things

[SBPGT]

We'll probably(leaving some opportunity for hope ) never know the limits of this motor? Unless some tuner shop like Undergorund Racing, etc. spends "their" time on R&D and "someone"(no one on here) else's $$$, we'll just have low budget, trial and error, garage builds to get info from. Inconsistent info, from different tunes, specs, parts, assembly and driver competence, etc...

But, not trying to discourage anyone. I remember "back in the day" when 8psi was pushing it, and everyone was running FMU's. We just need to keep pushing the boundries and learning together.

[P1P]

I got one thing to say about that and I'll make my point towards it. 2jz. With a non vvt motor you can make 700 HP with all the supporting miss that we have. You could even stretch the limits on a 1jz since it has the same comp as ours. Those engines are known for making big power because of strong factory pistons and rods with a Damn good tune. Our motor has everything their motor has, except for an aluminum block. No one here has broken a crank (to my knowledge). The 1jz and 2jz come with a dusty with aftermarket options of COP. We the same. Our down fall is Cinderella's own glass slipper for a transmission. Everyone who has bent a rod here bent it due to a tuning error. It was proven that a stock (junkyard) motor could hold 360whp (the panda) and if it wasn't for the fire it probably would've held more. I'm not saying we got the best engine in the world, just a better engine to start with than others.

this issue here is tuning and R&D

there are a few guys making more than a 1000hp with a 2jz without even cracking the motor open but the 2jz guys and the big names shops have spent many hours and money on R&D and that what makes the big difference.

to be honest and I know i will get flamed for this but no matter how you look at it guys who drive probes are cheap asses, everyone wants power but they want it at a cheap cost plus only a couple of members here think outside of the box and venture where no one else will go (Dan Sac, Mac, Matt Mass, FallGuy, Senseless) just to name a few, the rest just try to ride their nuts like they are god or copy their exact build a hope it works. no one here spends the money like the guys do that own other brand name cars. (honda, acura, mitsu, toyota, madza, gm, dodge)

long story short the kl motor is a capable motor, there have been 800hp kl's and even a 1000hp kl, but those motors had real money invested in them, and I am sorry to say most guys here wont spend that type of money or even close to that type of money

I saw a thread about don't let PT die (klzeporsche) well I hope it dont die, but it probally will one day not becos Damon didnt pay the light bill but because if no one does anything special people will slowly stop coming becos there is nothing new to read except someone going to ebay buying the cheapest parts and then half ass putting it together and then blowing the car up lol (old folk saying - YOU GET WHAT YO PAY FOR )


sorry for going way out with this post but these are a few things I kinda wanted to say for years, i had more but maybe another day

[blac_shine007]

That was somewhat on point. Make an adapter plate for another trans and build the shit out of the motor. Just use the winning recipe that made other motors so special and use it to your advantage. Like maybe a SRT4 neon or Nissan 6 speed LSD trans adaptor plate. Just an idea.

[mac1]

Everyone who has bent a rod here bent it due to a tuning error. It was proven that a stock (junkyard) motor could hold 360whp (the panda) and if it wasn't for the fire it probably would've held more.

his engineS where not tuned for longevity..........everyone single one of them was dyno tuned to the max and never backed off for safety. 360hp out of a stock KL is just not reasonable imho. He knew what would happen and just kept at it.

[mac1]

That was somewhat on point. Make an adapter plate for another trans and build the shit out of the motor. Just use the winning recipe that made other motors so special and use it to your advantage. Like maybe a SRT4 neon or Nissan 6 speed LSD trans adaptor plate. Just an idea.

yeah but then we are back to the old saying............."those who talk about it, never do and those who keep quiet, research and take their time and money will sometimes actually do it and post an end results then never to be heard from again".

People want to boost a 20y.o. outdated design which was never meant to handle any boost reliably without sacrificing creature comforts, they tend to want to hold on to the originality of the car and still keep up with what's considered fast in this new age of torqy mini-vans and 260hp grocerie getters with vvt, traction control and factory turbos to boot.

YOu people are just setting yourself up for failure, get over it and buy a 2nd car and make it race car status, have your fun, then jump in your nostalgic "bolt-on" Probe and be just another lame ass civilized car on the road for that day.

---------- Post added at 06:30 AM ---------- Previous post was at 06:28 AM ----------

to be honest and I know i will get flamed for this but no matter how you look at it guys who drive probes are cheap asses, everyone wants power but they want it at a cheap cost plus only a couple of members here think outside of the box and venture where no one else will go (Dan Sac, Mac, Matt Mass, FallGuy, Senseless) just to name a few, the rest just try to ride their nuts like they are god or copy their exact build a hope it works. no one here spends the money like the guys do that own other brand name cars. (honda, acura, mitsu, toyota, madza, gm, dodge)

long story short the kl motor is a capable motor, there have been 800hp kl's and even a 1000hp kl, but those motors had real money invested in them, and I am sorry to say most guys here wont spend that type of money or even close to that type of money

I saw a thread about don't let PT die (klzeporsche) well I hope it dont die, but it probally will one day not becos Damon didnt pay the light bill but because if no one does anything special people will slowly stop coming becos there is nothing new to read except someone going to ebay buying the cheapest parts and then half ass putting it together and then blowing the car up lol (old folk saying - YOU GET WHAT YO PAY FOR )

We drive a car that can be bought for $600 in running condition, of course we are cheap, it's called being middle class.

[concealer404]

Being "cheap" the way most of you are, is a recipe for disaster. Fully 50% or more of the turbo probes on here have no business being boosted. Fully 50% of the owners of turbo probes on here are not prepared for turbo car ownership.

Honestly, this thread is a good indication of such.

[P1P]

yeah but then we are back to the old saying............."those who talk about it, never do and those who keep quiet, research and take their time and money will sometimes actually do it and post an end results then never to be heard from again".

People want to boost a 20y.o. outdated design which was never meant to handle any boost reliably without sacrificing creature comforts, they tend to want to hold on to the originality of the car and still keep up with what's considered fast in this new age of torqy mini-vans and 260hp grocerie getters with vvt, traction control and factory turbos to boot.

YOu people are just setting yourself up for failure, get over it and buy a 2nd car and make it race car status, have your fun, then jump in your nostalgic "bolt-on" Probe and be just another lame ass civilized car on the road for that day.

---------- Post added at 06:30 AM ---------- Previous post was at 06:28 AM ----------



We drive a car that can be bought for $600 in running condition, of course we are cheap, it's called being middle class.

I semi understand your point about it being a 20 year old car out of date design, but so is the 93-98 toyota supra, 93-97 madza rx7, 92-95 crx/civic, 94-01 integra, 89-99 eclipse, 69-02 skyline

---------- Post added at 04:11 PM ---------- Previous post was at 04:10 PM ----------

Being "cheap" the way most of you are, is a recipe for disaster. Fully 50% or more of the turbo probes on here have no business being boosted. Fully 50% of the owners of turbo probes on here are not prepared for turbo car ownership.

Honestly, this thread is a good indication of such.

I would say more than 50%

maybe 80%