HP guesses in the new year.....

Another thing to consider is that once you get to the 400+rwhp range, premium pump gas isn't a very robust or reliable fuel to use. You assume risk with a turbo because you can easily turn boost up to make 500+whp, but pump gas wont support it. A big turbo kind of helps things in the detonation world because they spool when piston speeds are high, thus the cylinder pressures are lower. In other words....CORN.

I'm interested in this statement. I understand the general concept of octane and dynamic compression... but I have not seen something in writing that supports what you say. What happens if you have a SC based car that makes 400whp at 17 psi on pump gas and you install a turbo kit making 17 psi and still run pump gas? my guess would be that with the turbo kit would be pretty close to 500whp using pump gas. Or am i just misreading what you are saying?

Thanks,
Derek
 
that thing looks top shelf!! SCU does it again. You're a lucky young man Phil! is this the car with the 6 speed swap?

Yeah, this is the same car that I 6spd swapped a couple years ago. After I rowed that extra gear for the first time, I never looked back. Lol
 
I'm interested in this statement. I understand the general concept of octane and dynamic compression... but I have not seen something in writing that supports what you say. What happens if you have a SC based car that makes 400whp at 17 psi on pump gas and you install a turbo kit making 17 psi and still run pump gas? my guess would be that with the turbo kit would be pretty close to 500whp using pump gas. Or am i just misreading what you are saying?

Thanks,
Derek

Good morning


I agree with Mr. Derek until I read the following post by XR7 Dave. As I understand the information a 400 hp blower driven SC engine is close to a max out burning premium pump gas alone.

http://www.sccoa.com/forums/showthread.php?125838-400rwhp-on-91-octane&p=995139#post995139
 
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17psi on pump gas is pushing your luck, regardless of measured HP. Most people running this level of boost are using a supplement such as alcohol injection. Due to the increased exhaust temperatures with a turbocharger, boost levels that "seem" ok with a supercharger (typically light detonation) will result in severe detonation with a turbocharger. This is due primarily to the increased exhaust temperature.

You will make more HP with a turbo compared to a supercharger, exactly how much more is not a pencil and paper calculation. With the right fuel the power gains can be significant.
 
I'm interested in this statement. I understand the general concept of octane and dynamic compression... but I have not seen something in writing that supports what you say. What happens if you have a SC based car that makes 400whp at 17 psi on pump gas and you install a turbo kit making 17 psi and still run pump gas? my guess would be that with the turbo kit would be pretty close to 500whp using pump gas. Or am i just misreading what you are saying?

Thanks,
Derek

Yes, there will be a HP difference when going turbo because you aren't driving a blower, but you still assume the same risk. Since the turbos are spooling around 2800-3200 rpm, that's still far below the 5200 HP / TQ crossover point, so cylinder pressures are still a concern for turbos.

Part of the point I was trying to make is that this group has good awareness about limits of how much one can overdrive the blowers and they have a mechanical inefficiency posing as a safety-net built in to them that prevents too much boost being ran. With a turbo, you push a couple of buttons in your car, or you get out and turn the boost controller and you go from a pet to a monster in seconds. So using a fuel that can't handle a monster, but can feed a pet only is a recipe for disaster.

I'm sure Dave has experience repairing detonated engines because of pump gas at levels even lower than 400rwhp. Considering magnitude of affect, there are many other engines that get destroyed because of pump gas being non-robust for their power levels. It's all too common.
 
Yes, there will be a HP difference when going turbo because you aren't driving a blower, but you still assume the same risk. Since the turbos are spooling around 2800-3200 rpm, that's still far below the 5200 HP / TQ crossover point, so cylinder pressures are still a concern for turbos.

Part of the point I was trying to make is that this group has good awareness about limits of how much one can overdrive the blowers and they have a mechanical inefficiency posing as a safety-net built in to them that prevents too much boost being ran. With a turbo, you push a couple of buttons in your car, or you get out and turn the boost controller and you go from a pet to a monster in seconds. So using a fuel that can't handle a monster, but can feed a pet only is a recipe for disaster.

I'm sure Dave has experience repairing detonated engines because of pump gas at levels even lower than 400rwhp. Considering magnitude of affect, there are many other engines that get destroyed because of pump gas being non-robust for their power levels. It's all too common.

So everything you say makes sense, which is what I would expect from you. Is there a formula for other grades of fuel. I am running only 100 octane unlead at this time. What would be the HP limit on that. I know timing and other factors apply, just a rough guess

Ken
 
thanks for the replies! I'm not sure I can see that it is worth the effort/expense to convert to a turbo (in my case) if I only want to run pump gas. E85 is very hit or miss around here, so it is not practical to switch fuel in my case. If 15-17psi (or 375-400whp) is the approximate octane limit of pump gas, and you are already there, why convert? or am i missing something? It seems that this turbo set up is a cheaper way to get to where Im currently at :)
 
Where you are at now you'll need to switch fuel or run snow methonal injection kit like most of us and up the boost. I've always run pump 93 and alky injection as E85 is non existent in my area, and yes made 506 on pump 93. Then would be the decision to find a twin screw or resort to the dark side.
 
Where you are at now you'll need to switch fuel or run snow methonal injection kit like most of us and up the boost. I've always run pump 93 and alky injection as E85 is non existent in my area, and yes made 506 on pump 93. Then would be the decision to find a twin screw or resort to the dark side.

Same here, making right around 500 rwhp with 93 octane and methanol injection using the 2.3 whipple at about 21 pounds of boost. Could make more power switching to E85, but it's not widely available in the STL area. I already did the turbo thing and while I agree that the power they make is very impressive, it's not all peaches and cream. Takes some time to sort out the combo and managing the extra heat under the hood is also something to consider. That said, it's really cool, when you can smoke the tires from a 70 mph roll on the highway.

David
 
There is no comparison between a roots blower at 17psi and a 62mm turbo at 17psi. The turbo is going to move more air. I've got logs showing a 62mm a 16-18psi and max maf ad counts were 820's, load 160. Switched to an s366 and 870/190. So the 66mm was moving more air as it showed in fuel trims and mph at the strip.
 
i didn't mean to derail the thread... It is an interesting discussion about octane limits. something I was not all that familiar with, but something one must consider in deciding what they want out of their car.
 
i didn't mean to derail the thread... It is an interesting discussion about octane limits. something I was not all that familiar with, but something one must consider in deciding what they want out of their car.

I understand. Everyone has their own set of concerns and interests based on their unique situation which is a combination of their mods and their expectations. However, I think the thing that has been skirted around like the proverbial elephant in the room, is that we are all looking for ways to make our cars more fun.

A car is no fun if the power band isn't where you can use it, or if the boost range is inaccessible due to cylinder pressure or rpm, etc. From my perspective, and since I do not have the luxury of owning just one project car, I can take this back to 2001 when I had a well modded M90 based car. It made 12-13psi and I ran 12.5's with it under ideal conditions. That car was as fast as most of the cars you guys are driving now so I guess I should have been happy. But the two things that bothered me most about it was that the power band started at 3000rpm and petered off from there. Guys that's not fun, I don't care how fast it is. If you can't feel the power band, then it just takes the thrill out. I was used to higher HP NA engines that have a definite power band that you can feel come in with rpm. My car didn't have that.

The other thing that my M90 car had was ridiculous wheel hop. The torque comes in so fast and so hard that the 5spd was murder to try and put the power down. I literally broke two axles at the same time on the track. When I switched to the AR I found that the car wheel hopped less. It made about 80rwhp more, but it hopped less. The car also developed a bit of a power band. It was a strange sensation to be able to hook the tires in 3rd and then feel them start to spin again as it hit about 4800-5000rpm. This reminded me more of my old NA big block days. So it was fun.

So why bother looking at turbo's? Well things change. Technology improves, things become readily available that weren't a few years ago, information is much more readily available, it's just different today.

I considered doing turbos instead of the AR's back in 2003 when I started all this. But information was scarce and frankly it just didn't seem viable as there were too many unknowns. Not to mention the angst among SC owners at the time against anything not M90. It was just to big of a step, and furthermore, it wasn't necessary. When a 2003 Cobra made 360rwhp, making 400rwhp was enough to turn heads. Of course we all know what 400rwhp will do for you in 2017. No one could have predicted that we'd have bone stock Mustangs making 400rwhp. Things change.

For now we are looking at a new model of how to make a turbo work best for an SC. We have started out with a small turbo on a mild engine so that someone buying a car or starting to mod it now can have an idea of how changing over to a turbo now before spending a lot of money on a supercharger, can benefit them. Absolutely we know how to make big power with turbo, that has never been a question. The question has always been, how can we make that practical or achievable for a beginner or for someone with milder expectations. We have started there with this kit.

So far I can tell you a few things - first of all, wheel hop is almost completely eliminated. Now even a 5spd car builds torque smoothly like an auto rather than violently like we are all used to. Second, the engine now has an amazing power band. It's not that the turbo creates this power band more than it actually "releases" it. No longer does the motor act like it has a brake being gradually applied with rpm. The engine simply runs the rpm band it was designed to operate in. Well, and plus a little. That's fun.

Which brings me to the fun factor. Take the wheel hop down a notch - or 2 - and take the power band up a notch - or 2 - and that's where the fun factor is. It takes a lot more doing to properly match a hot side with the airflow and boost you want to run for any particular given application, but the results are worth it. It's not a "one size fits all" deal because the needs of a 9000rpm 1.6L engine are quite different from a 5000rpm 3.8L even if the HP outputs are the same. A turbo that works great on the 1.6 will be a mismatch on the 3.8. It's not like the supercharger world where for the most part bigger is better.

All that aside, people just want to know "how much power can I make and how much will it cost". HP/$$. Well I'm not going to have that discussion with you. :) Physics and science don't step aside just so that the SC world can languish. The science is proven and the fact is you can't make more power any other way, so this is the way we are going. We'll figure out what works best for us and maximize our results. If you are passionate about your SC then most likely this will be part of your future. SCUI has I think 5 supercharger kits on pre-order at the moment but after that we won't be making any more.

It's time to embrace the future, and the future includes a turbo and E85. You will always be able to make more power on pump gas with a turbo than you can with a Supercharger, most likely in the neighborhood of 50-80rwhp, but the real power lies in the ability to run 20-25psi if you really want to, whether it's on race fuel or E85. It's frankly more fun than a supercharger. Especially on the street and particularly at lower boost levels where most of you spend 99% of your time. All the fast kids will be doing it. :)
 
I understand. Everyone has their own set of concerns and interests based on their unique situation which is a combination of their mods and their expectations. However, I think the thing that has been skirted around like the proverbial elephant in the room, is that we are all looking for ways to make our cars more fun.

A car is no fun if the power band isn't where you can use it, or if the boost range is inaccessible due to cylinder pressure or rpm, etc. From my perspective, and since I do not have the luxury of owning just one project car, I can take this back to 2001 when I had a well modded M90 based car. It made 12-13psi and I ran 12.5's with it under ideal conditions. That car was as fast as most of the cars you guys are driving now so I guess I should have been happy. But the two things that bothered me most about it was that the power band started at 3000rpm and petered off from there. Guys that's not fun, I don't care how fast it is. If you can't feel the power band, then it just takes the thrill out. I was used to higher HP NA engines that have a definite power band that you can feel come in with rpm. My car didn't have that.

The other thing that my M90 car had was ridiculous wheel hop. The torque comes in so fast and so hard that the 5spd was murder to try and put the power down. I literally broke two axles at the same time on the track. When I switched to the AR I found that the car wheel hopped less. It made about 80rwhp more, but it hopped less. The car also developed a bit of a power band. It was a strange sensation to be able to hook the tires in 3rd and then feel them start to spin again as it hit about 4800-5000rpm. This reminded me more of my old NA big block days. So it was fun.

So why bother looking at turbo's? Well things change. Technology improves, things become readily available that weren't a few years ago, information is much more readily available, it's just different today.

I considered doing turbos instead of the AR's back in 2003 when I started all this. But information was scarce and frankly it just didn't seem viable as there were too many unknowns. Not to mention the angst among SC owners at the time against anything not M90. It was just to big of a step, and furthermore, it wasn't necessary. When a 2003 Cobra made 360rwhp, making 400rwhp was enough to turn heads. Of course we all know what 400rwhp will do for you in 2017. No one could have predicted that we'd have bone stock Mustangs making 400rwhp. Things change.

For now we are looking at a new model of how to make a turbo work best for an SC. We have started out with a small turbo on a mild engine so that someone buying a car or starting to mod it now can have an idea of how changing over to a turbo now before spending a lot of money on a supercharger, can benefit them. Absolutely we know how to make big power with turbo, that has never been a question. The question has always been, how can we make that practical or achievable for a beginner or for someone with milder expectations. We have started there with this kit.

So far I can tell you a few things - first of all, wheel hop is almost completely eliminated. Now even a 5spd car builds torque smoothly like an auto rather than violently like we are all used to. Second, the engine now has an amazing power band. It's not that the turbo creates this power band more than it actually "releases" it. No longer does the motor act like it has a brake being gradually applied with rpm. The engine simply runs the rpm band it was designed to operate in. Well, and plus a little. That's fun.

Which brings me to the fun factor. Take the wheel hop down a notch - or 2 - and take the power band up a notch - or 2 - and that's where the fun factor is. It takes a lot more doing to properly match a hot side with the airflow and boost you want to run for any particular given application, but the results are worth it. It's not a "one size fits all" deal because the needs of a 9000rpm 1.6L engine are quite different from a 5000rpm 3.8L even if the HP outputs are the same. A turbo that works great on the 1.6 will be a mismatch on the 3.8. It's not like the supercharger world where for the most part bigger is better.

All that aside, people just want to know "how much power can I make and how much will it cost". HP/$$. Well I'm not going to have that discussion with you. :) Physics and science don't step aside just so that the SC world can languish. The science is proven and the fact is you can't make more power any other way, so this is the way we are going. We'll figure out what works best for us and maximize our results. If you are passionate about your SC then most likely this will be part of your future. SCUI has I think 5 supercharger kits on pre-order at the moment but after that we won't be making any more.

It's time to embrace the future, and the future includes a turbo and E85. You will always be able to make more power on pump gas with a turbo than you can with a Supercharger, most likely in the neighborhood of 50-80rwhp, but the real power lies in the ability to run 20-25psi if you really want to, whether it's on race fuel or E85. It's frankly more fun than a supercharger. Especially on the street and particularly at lower boost levels where most of you spend 99% of your time. All the fast kids will be doing it. :)


So when will you start producing a viable turbo kit? Or at least a hotside? I love the powerband of my ecoboost it really growson you! I am to the point where I feel like I have hit a 15psi road block with an m90.
 
Thanks for all of the great information. Clean slate on my seized motor 95.
Will be following this.
Creighton
 
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Dave puts it into perspective about progressing a community. Of course, you can get a 3.4 Whipple and put it on there, and I'd love for someone to do that. Then you're talking about hood clearance issues and modifying a section of a firewall. Turbo is just a more concise package that has great capabilities and street manners.

Of course it depends on what your requirements and goals are. To each their own.

So everything you say makes sense, which is what I would expect from you. Is there a formula for other grades of fuel. I am running only 100 octane unlead at this time. What would be the HP limit on that. I know timing and other factors apply, just a rough guess

Not to change the momentum of Dave's post:

I'm not aware of a formula; but there's plenty of people out there that run the same fuel to get an experimental estimation. E85 pump will let you run around 1000whp in a 6 cylinder. Probably more, but i'm not comfortable doing more with a 6 cylinder. Race E85 or E99 can make much more. For 100 octane gas, I'm not sure what its limit would be. I think 100 octane would only be enough to feel comfortable making 450-500whp using a turbo. I wouldn't use it as a way to make much more power than 93. Someone would need to put EGT on all cylinders to be able to see how much power you can safely make. Nobody really does that around here, so headgaskets/bearings are what tells the story, which is slow feedback.

You have to be careful when thinking octane. There are other factors than octane that are to be considered in the capability of a fuel. Latent heat of vaporization, distillation end points, and octane are just some of the factors to consider. To simplify a way of thinking, a fuel becomes dangerous to an engine whenever cylinder temperatures start to rise to the point of detonation. Some fuels have low temperature distillation end points and the enthalpy of vaporization is low, which keeps cylinder temperatures lower. Octane compounds with their effect by allowing the fuel to burn slower. E85 (or alcohols for that matter) are great for lowering risk of detonation because they burn much cooler than gas. Gas needs a lot of octane because the atomization does not have as much cooling effect as alcohols. E85 is around 105 octane and it burns cooler than gas.

Double Whammy
 
For 100 octane gas, I'm not sure what its limit would be. I think 100 octane would only be enough to feel comfortable making 450-500whp using a turbo. I wouldn't use it as a way to make much more power than 93. Someone would need to put EGT on all cylinders to be able to see how much power you can safely make. Nobody really does that around here, so headgaskets/bearings are what tells the story, which is slow feedback.
You and corey have made big turbo HP. What fuel are or were running, E85? I can get 110 but its leaded and would foul my O2 sensors. E 85 is everywhere here in Omaha. I am running 80lb injectors now but don't know if that would be enough to run E85 to run well into the 500 range. That and a whole new tune. E85 would be a lot cheaper than what Im doing now. A lot to think about

Ken
 
time to add something here..

years ago I took a brand new nos engine and added a bunch of stuff to it.. I had the best of the best and had it tuned. that thing was a rocket ship. Even when Dave D tuned it he was surprised by how everything worked together and how much power it made.. Then one day it went BOOM and I do mean BOOM.. I guess this was a simple case of over riding the gas that was in this car as has been talked about here.. I do beleive that there is a lot of truth to the over killing of pump gas in these cars... Just had to say something on that matter....Rich
 
I know that this is a turbo NA split port discussion, but as someone that has beefed up their NA 3.8 split port Mustang (higher compression custom ported heads, cam, tune, 4.10's etc etc), I can say that they're capable of being pretty badass. What I like about the stock Ford split ports is the multi-angle valve job.....it's really effective. I flow tested them with a crude vacuum setup, and the exhaust ports, there's this ridge right beneath the valve port that directs lower lift air from a slow moving area of the valve out the sides, and speeds it up around to the exhaust port exit side. I had a spare pair of heads that someone had removed that ridge, and with a string/ vacuum test, it lost that velocity. It was interesting to do a few tests and try a few different things and then see what worked the best.
 
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