Most compression you’d run on boost
If your ideas about being unable to drop charge temps until the fluid was near the boiling point were correct, then that would invalidate the concept of evaporative cooling. I understand that the charge air cooling isn't nearly what people think it is, but no need to exaggerate the situation.
I don't think I invalidated anything. Evaporative cooling takes time to pull heat from an object. There is VERY little time to do that, especially in a highly pressurized charge pipe. We have the data from Kevin Jewers dyno cell testing that more than proves this. He used methanol as his base fuel. And replaced as much as half his total fueling pre turbo. Using the methanol pre-turbo strictly to cool the charge. He was able to bring the charge temps right around mid 150's. No matter how much more he sprayed pre turbo and pulled from the rails... the charge temps did not get any lower.
Last edited by Forcefed86; Jan 13, 2024 at 10:35 PM.
I believe I'm one of the few people who have an actual real world street driven car experience changing NOTHING except the compression ratio. Many years ago, I had a 408 with 11.4 to 1 static compression ratio. I wanted to switch from nitrous to boost and was limited to 91 octane pump. We changed NOTHING except the pistons to lower the compression ratio to 9.5 to 1. Same heads, cam, intake, exhaust, everything.
That car lost a **** load of low to mid rpm torque and throttle response. Top end wide open didn't seem to change much, but the car was way less fun to drive as it was a daily driver 3 seasons of the year and put away when there was snow/ice on the roads only.
Here is a before and after sound clip video of that car...
That car lost a **** load of low to mid rpm torque and throttle response. Top end wide open didn't seem to change much, but the car was way less fun to drive as it was a daily driver 3 seasons of the year and put away when there was snow/ice on the roads only.
Here is a before and after sound clip video of that car...
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I believe I'm one of the few people who have an actual real world street driven car experience changing NOTHING except the compression ratio. Many years ago, I had a 408 with 11.4 to 1 static compression ratio. I wanted to switch from nitrous to boost and was limited to 91 octane pump. We changed NOTHING except the pistons to lower the compression ratio to 9.5 to 1. Same heads, cam, intake, exhaust, everything.
That car lost a **** load of low to mid rpm torque and throttle response. Top end wide open didn't seem to change much, but the car was way less fun to drive as it was a daily driver 3 seasons of the year and put away when there was snow/ice on the roads only.
Here is a before and after sound clip video of that car...
https://youtu.be/CHEZxMGGPG8?si=iglBqLYEcSUhiRAr
That car lost a **** load of low to mid rpm torque and throttle response. Top end wide open didn't seem to change much, but the car was way less fun to drive as it was a daily driver 3 seasons of the year and put away when there was snow/ice on the roads only.
Here is a before and after sound clip video of that car...
https://youtu.be/CHEZxMGGPG8?si=iglBqLYEcSUhiRAr
I didn't watch the video, but I do have experience to speak on actual street driving differences between 11.4 to 1 and 9.5 to 1 compression. I only speak about what I have actually experienced nothing more.
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I saw the title and I can guess where he was going as I've seen plenty of data on this where more compression doesn't add that much power. I work 12 hour days plus spent the rest of my time yesterday shoveling the more than foot of snow we got so I don't have time to watch a video that is going to tell me something I've already heard before.
I think it's worth mentioning my experience with changing compression since most of us are talking about street cars and lower compression definitely makes a difference in the fun factor due to lower throttle response and low rpm torque below where most dyno runs start. Dyno numbers don't always tell the full story, but I have real world street driving experience changing nothing but compression.
Just for the sake of clarity, do you dispute what I'm sharing from personal experience?
Have you actually changed nothing but a significant compression change and have real world experience you want to share ?
Not saying it's the case here but the internet is very good at beating up and telling people they are wrong about things they've actually done by people that haven't actually done the things they are speculating about.
I think it's worth mentioning my experience with changing compression since most of us are talking about street cars and lower compression definitely makes a difference in the fun factor due to lower throttle response and low rpm torque below where most dyno runs start. Dyno numbers don't always tell the full story, but I have real world street driving experience changing nothing but compression.
Just for the sake of clarity, do you dispute what I'm sharing from personal experience?
Have you actually changed nothing but a significant compression change and have real world experience you want to share ?
Not saying it's the case here but the internet is very good at beating up and telling people they are wrong about things they've actually done by people that haven't actually done the things they are speculating about.
Last edited by BCNUL8R; Jan 10, 2024 at 03:58 AM.
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It isn't just the unreliability of the meth system. It's the meth system + the wet cooler pump + the hobs switch + the redundant fuel pump +, +, +. It's pretty easy to end up in a spot where you have a decent collection of switches and bits of potential hidden failures where if any one component fails before you go WOT you may drive over parts.
In heavy industry, aircraft, space, etc... there is a whole science behind failure points that will never resonate with this crowd, but as an example: If you have five widgets on your car where a failure of that device can occur before you go WOT (and you don't know about it) and each of those widgets work 999 out of 1000 times, the odds of you having a potential engine ending event for a daily driver (5 days a week, 12 months a year) is ~100% within the first year. The probabilities get pretty bad, pretty quickly.
If you don't drive the car that much, great - all that added complexity will never catch up to you. Or, if this is a race car and you test everything before a track day, also great, it is no longer a hidden failure. There is a reason a lot of folks have some sort of anecdotal story about a friend or themselves where a hobbs switch or a meth pump took out an engine - it isn't because they were unlucky or bought a bad system, its because it doesn't take a lot of these types of devices on a regularly driven car to make a failure very probable.
In heavy industry, aircraft, space, etc... there is a whole science behind failure points that will never resonate with this crowd, but as an example: If you have five widgets on your car where a failure of that device can occur before you go WOT (and you don't know about it) and each of those widgets work 999 out of 1000 times, the odds of you having a potential engine ending event for a daily driver (5 days a week, 12 months a year) is ~100% within the first year. The probabilities get pretty bad, pretty quickly.
If you don't drive the car that much, great - all that added complexity will never catch up to you. Or, if this is a race car and you test everything before a track day, also great, it is no longer a hidden failure. There is a reason a lot of folks have some sort of anecdotal story about a friend or themselves where a hobbs switch or a meth pump took out an engine - it isn't because they were unlucky or bought a bad system, its because it doesn't take a lot of these types of devices on a regularly driven car to make a failure very probable.
Running 16 PSI in high gear here at 10.6:1 in my cammed 5.7. I saw similar results as another member on the 1st page. Before WMI I was stuck at around 10 degrees and 10 PSI or I would get knock on 93. Adding a single M10 nozzle and windshield washer fluid let me go to 16 PSI and 12 degrees with no signs of knock.
Its common sense to say that ANY setup that dropped basically 2 whole points in compression would have a noticeable difference in response and power. I just built a 5.3 that’s a little over 13:1. I’m sure it’ll be a lot angrier than the 9:1 5.3’s I’m use to playing with. But I’m not going to turbo this motor. If you are running an NA setup you need as much help as you can get run all the compression! But since you are basically shrinking the size of the CC the higher you go compression wise… the gains taper off quick the higher you go. So you are eventually losing power on a boosted motor by adding unnecessary compression.
Id say if setup correctly, that a 400+cube motor at 9.5:1 *should* be a tire frying responsive monster of a street car NA. So if you are lacking power in the low and mid range, you likely have too much cam/gear/intake in it for your desired power band and weight.
Also don’t you run a procharger? They have a lazy RPM dependent boost curve makes a huge difference. Turbo guys don’t have to deal with that. If you had a smallish turbo on it, you’d gain that lost response back and likely even more… Not that prochrgers can’t be bad ****’s! But they have an extra hurtle to jump response wise. Our small tire track record is set by a small block procharged car…
Id say if setup correctly, that a 400+cube motor at 9.5:1 *should* be a tire frying responsive monster of a street car NA. So if you are lacking power in the low and mid range, you likely have too much cam/gear/intake in it for your desired power band and weight.
Also don’t you run a procharger? They have a lazy RPM dependent boost curve makes a huge difference. Turbo guys don’t have to deal with that. If you had a smallish turbo on it, you’d gain that lost response back and likely even more… Not that prochrgers can’t be bad ****’s! But they have an extra hurtle to jump response wise. Our small tire track record is set by a small block procharged car…
Its common sense to say that ANY setup that dropped basically 2 whole points in compression would have a noticeable difference in response and power. I just built a 5.3 that’s a little over 13:1. I’m sure it’ll be a lot angrier than the 9:1 5.3’s I’m use to playing with. But I’m not going to turbo this motor. If you are running an NA setup you need as much help as you can get run all the compression! But since you are basically shrinking the size of the CC the higher you go compression wise… the gains taper off quick the higher you go. So you are eventually losing power on a boosted motor by adding unnecessary compression.
Id say if setup correctly, that a 400+cube motor at 9.5:1 *should* be a tire frying responsive monster of a street car NA. So if you are lacking power in the low and mid range, you likely have too much cam/gear/intake in it for your desired power band and weight.
Also don’t you run a procharger? They have a lazy RPM dependent boost curve makes a huge difference. Turbo guys don’t have to deal with that. If you had a smallish turbo on it, you’d gain that lost response back and likely even more… Not that prochrgers can’t be bad ****’s! But they have an extra hurtle to jump response wise. Our small tire track record is set by a small block procharged car…
Id say if setup correctly, that a 400+cube motor at 9.5:1 *should* be a tire frying responsive monster of a street car NA. So if you are lacking power in the low and mid range, you likely have too much cam/gear/intake in it for your desired power band and weight.
Also don’t you run a procharger? They have a lazy RPM dependent boost curve makes a huge difference. Turbo guys don’t have to deal with that. If you had a smallish turbo on it, you’d gain that lost response back and likely even more… Not that prochrgers can’t be bad ****’s! But they have an extra hurtle to jump response wise. Our small tire track record is set by a small block procharged car…
If someone had that 408 at 9.5 to 1 they might be really happy with its response, but after going from 11.4 to 1 to that low compression with no other changes it was very noticeable. From a roll you had to be in the right gear/rpm to get good response where at 11.4 you may only need to be in 3rd at low rpm to get the response and break the tires loose where at 9.5 to 1 you needed to go down to 2nd in that same scenario to make sure you were in high rpms. If that makes sense...lol...it's hard to explain and I probably did a poor job of it.
Prochargers do benefit from more cubic inches, but at 1000 rwhp I find myself taking timing out in the midrange to try to get down the track. I only have a 377 at 10.6 to 1 and 20 psi now in the current car.
Last edited by BCNUL8R; Jan 10, 2024 at 05:26 PM.
This actually heavily resonates with me given that I get involved with failure mode analysis in the transportation industry. That's why when I built my kit from scratch I added a hobbs switch at the nozzle that feeds an LED in my face during WOT. As long as that little green light is only on but stays on at WOT, I have reasonable certainty that my WMI kit is active.
Im amazed something like this hasn't really caught on. It's cheap and effective and as close as it gets to guaranteeing you have water/meth flow. All these other "fail-safes" where they look at voltage and current of the motor aren't really fail-safes in my world. Borrow away! 
Im amazed something like this hasn't really caught on. It's cheap and effective and as close as it gets to guaranteeing you have water/meth flow. All these other "fail-safes" where they look at voltage and current of the motor aren't really fail-safes in my world. Borrow away!
I have an Alky Control kit from Julio and the one I have presumed flow from current draw of the motor, not from a pressure transducer. If that was updated then that's awesome!
The old pumps had a pressure sensor built into the head of the pump, the newer pumps as of a few years ago no longer had that integral sensor so they moved the sensor to the line going to the nozzle. I've not seen one of their kits that used strictly current draw from the motor to infer flow.
The old pumps had a pressure sensor built into the head of the pump, the newer pumps as of a few years ago no longer had that integral sensor so they moved the sensor to the line going to the nozzle. I've not seen one of their kits that used strictly current draw from the motor to infer flow.
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His example appears flawed at around 29 minutes. He's inferring that you lose power from a higher compression ratio for the SAME NA HP used as the starting point. Which is technically true, but then he makes a brief statement that its not taking into account thermal efficiencies from the higher compression ratio. He still says that you'll lose power overall even with the thermal efficiency gain. If you're at 8:1 NA making 200whp and you swap to 12:1 chances are more often then not that your setup won't stay at 200whp. So in the 45 PSI of boost example, as long as youre not turbo or octane limited, etc. you'll gain power going from 12:1 over 8:1.
I am guessing that you are inferring some things that I do not think that he is implying. Where did he talk about what that 2.0 Liter engine at 45psi would make na at any compression ratio? My guess is that na the 12:1 engine would make more power. This is complicated by the fact that you are using the word "infer" when you may mean "imply". I am not being a word **** here as they have different meanings and I honestly do not know for sure.