76mm turbo or D1?

[Towelly]

I vote Turbo.

 

[Germeezy3]

Not quite.

First let me say that yes, a turbo will make more peak power (and torque) at the same boost as a centri. I love turbos, I've had several turbo cars, and they really do out-power (peak #'s) just about every power adder out there, boost for boost.

The only thing turbos don't have, which is what my "problem" with them is, is power under the curve. They're either on or off. You have virtually nothing under 3500 rpm for hp/tq. You're either waiting for boost, or you're spinning tires. There really isn't an "in-between."

Now, I'm running an F1C, wastegated. I see full boost (14lbs) by about 4500 rpm (results may vary depending on your target boost pressure and altitude). I have 6 lbs at 2500, and 9 lbs by 3500. The car PULLS from 1500. It's not tire spinning torque down low like a roots type blower, it's more linear and smooth. It doesn't hit like a turbo either.

However, because I'm spinning the blower that hard, at lower boost (14 lbs is low with a pullied down F1) it doesn't make killer numbers up top. My hp and torque really fall off around 6200, simply from the HP it takes to spin the blower that hard. But, if I run a larger pulley and slow the blower down, I lose more of the low end torque but gain my upper RPM power back. So I can "tune" my power band depending on which pulley I run, and peak boost is always the same based on my wastegate setting. This is mostly because I'm running a large, very capable blower. A D1 probably won't be as effective, at least at my altitude (5000 feet).

So, in the world of "this power adder is better than that power adder" I'm certainly not going to say one is better than the other as I beleive they all have their place. But I feel my setup is a NICE compromise between them all. Plus I get the pleasure of listening to that F1 sing at just about every RPM, especially idle.

Anyway, there's my .02.

My suggestion, decide what type of power-band you want, what hp number you're looking for, what type of driving/racing you're going to be doing the most, and then look at which power adder fits those needs the best. And maybe go for a ride in each if you can.

Are your experiences with singles or twins? Are we talking cast wheel journal bearing turbos? Because a lot has changed in the turbo world fairly recently.

 

[Marc s]

Not quite.

First let me say that yes, a turbo will make more peak power (and torque) at the same boost as a centri. I love turbos, I've had several turbo cars, and they really do out-power (peak #'s) just about every power adder out there, boost for boost.

The only thing turbos don't have, which is what my "problem" with them is, is power under the curve. They're either on or off. You have virtually nothing under 3500 rpm for hp/tq. You're either waiting for boost, or you're spinning tires. There really isn't an "in-between."

Now, I'm running an F1C, wastegated. I see full boost (14lbs) by about 4500 rpm (results may vary depending on your target boost pressure and altitude). I have 6 lbs at 2500, and 9 lbs by 3500. The car PULLS from 1500. It's not tire spinning torque down low like a roots type blower, it's more linear and smooth. It doesn't hit like a turbo either.

However, because I'm spinning the blower that hard, at lower boost (14 lbs is low with a pullied down F1) it doesn't make killer numbers up top. My hp and torque really fall off around 6200, simply from the HP it takes to spin the blower that hard. But, if I run a larger pulley and slow the blower down, I lose more of the low end torque but gain my upper RPM power back. So I can "tune" my power band depending on which pulley I run, and peak boost is always the same based on my wastegate setting. This is mostly because I'm running a large, very capable blower. A D1 probably won't be as effective, at least at my altitude (5000 feet).

So, in the world of "this power adder is better than that power adder" I'm certainly not going to say one is better than the other as I beleive they all have their place. But I feel my setup is a NICE compromise between them all. Plus I get the pleasure of listening to that F1 sing at just about every RPM, especially idle.

Anyway, there's my .02.

My suggestion, decide what type of power-band you want, what hp number you're looking for, what type of driving/racing you're going to be doing the most, and then look at which power adder fits those needs the best. And maybe go for a ride in each if you can.

Good info, I appreciate it.

I already have the D1 on the car and it makes good power. With a 4.13" pulley it made 569 @ 6400 and 604 at 6800. My engine is currently apart and now would be the time to decide if a turbo setup would better for me. There probably is no best FI for this car because I drag race, road race, and autoX it. I think I will stick with the Procharger, put the 3.55" pulley on it with the new engine and be happy with whatever HP it makes at 20lbs's of boost. Hoping for around 650whp. if I fall short, I can always upgrade to a F1. I really have no goal for this car other than to make enough HP to run 134mph in the 1/4. I don't want to deal with a chassis cert or being beat by ZR1's.

 

[Germeezy3]

Good info, I appreciate it.

I already have the D1 on the car and it makes good power. With a 4.13" pulley it made 569 @ 6400 and 604 at 6800. My engine is currently apart and now would be the time to decide if a turbo setup would better for me. There probably is no best FI for this car because I drag race, road race, and autoX it. I think I will stick with the Procharger, put the 3.55" pulley on it with the new engine and be happy with whatever HP it makes at 20lbs's of boost. Hoping for around 650whp. if I fall short, I can always upgrade to a F1. I really have no goal for this car other than to make enough HP to run 134mph in the 1/4. I don't want to deal with a chassis cert or being beat by ZR1's.

The one thing I will say especially knowing the current tuning situation, a turbo is going to take a whole new tune and some tuning time. With all of the things you do with the car a Procharger may be the best if your not keen on changing tunes and adjusting boost levels depending on what your doing.

Plus you have had very good luck with the unit and you are used to how it delivers power.

 

[Marc s]

The one thing I will say especially knowing the current tuning situation, a turbo is going to take a whole new tune and some tuning time. With all of the things you do with the car a Procharger may be the best if your not keen on changing tunes and adjusting boost levels depending on what your doing.

Plus you have had very good luck with the unit and you are used to how it delivers power.

I agree, I do like the way I can control the power coming out of the corners with the Procharger. I have never driven a high HP turbo car though. The only turbo car I ever had was a 412whp Stage3 SRT4 that was setup for road racing. The power deliver was all or nothing. I would love the opportunity to drive a high HP rear drive turbo car. I just don't know anyone around here that has one.

 

[19COBRA93]

Are your experiences with singles or twins? Are we talking cast wheel journal bearing turbos? Because a lot has changed in the turbo world fairly recently.

Both single and twin. But yes, they were cast wheel standard bearing turbos. I understand there are some new billet wheel ball bearing turbos that spool really quick, which is great, but they still "hit" pretty hard, and if you're trying to autocross or road race, that isn't what you want. And they're expensive...Not that an F1 is any sort of cheap alternative.

. There probably is no best FI for this car because I drag race, road race, and autoX it.

That's actually why I chose the route that I have. I also drag race, road race and autocross. I need something that is very versatile, and has a smooth broad powerband.

I agree, I do like the way I can control the power coming out of the corners with the Procharger. I have never driven a high HP turbo car though. The only turbo car I ever had was a 412whp Stage3 SRT4 that was setup for road racing. The power deliver was all or nothing. I would love the opportunity to drive a high HP rear drive turbo car. I just don't know anyone around here that has one.

With my turbo cars I had to get on the throttle early coming out of a turn to get the turbos spooled up, but if they came on too quick (if I were higher in the RPM), they'd hit too hard and I'd lose the rearend. It was a game of lag and tire spin. I guess I could have really turned the boost down to 5 or 6 lbs to keep it more managable.

 

[Marc s]

As a general rule, how much more HP will the F1 make over the D1 at the same boost?

 

[Germeezy3]

Both single and twin. But yes, they were cast wheel standard bearing turbos. I understand there are some new billet wheel ball bearing turbos that spool really quick, which is great, but they still "hit" pretty hard, and if you're trying to autocross or road race, that isn't what you want. And they're expensive...Not that an F1 is any sort of cheap alternative.



That's actually why I chose the route that I have. I also drag race, road race and autocross. I need something that is very versatile, and has a smooth broad powerband.



With my turbo cars I had to get on the throttle early coming out of a turn to get the turbos spooled up, but if they came on too quick (if I were higher in the RPM), they'd hit too hard and I'd lose the rearend. It was a game of lag and tire spin. I guess I could have really turned the boost down to 5 or 6 lbs to keep it more managable.

A lot of that is dependent on the setup and the boost levels, a low boost setup using an EBC will not have that sudden of an onset of boost. I was very close to pulling the trigger on a 700 rwhp twin turbo C6 and the boost onset was very gradual and smooth...it would spin the tires at 90 mph but it never felt out of control.

But I do agree with you for a set it and forget it car that will do all of those things with one tune and not messing with it, very hard to beat a Procharger also as far as power band suitable for road racing and drag racing.

 

[19COBRA93]

As a general rule, how much more HP will the F1 make over the D1 at the same boost?

Hard to say really. At lower boost numbers the D1 will probably make more power. The harder you spin it though, the more the F1 will really shine. The D1 will be pretty maxed out at 20 psi, the F1 will have a LOT of room to grow beyond that, and will be more efficient at that level as well. Something also to consider, the D1 is 4.10:1 geared, and the F1's are 5.40:1 geared so boost comes on quick. They do take more HP to spin though which is why you'll see the real gains at the higher boost levels.

A lot of that is dependent on the setup and the boost levels, a low boost setup using an EBC will not have that sudden of an onset of boost. I was very close to pulling the trigger on a 700 rwhp twin turbo C6 and the boost onset was very gradual and smooth...it would spin the tires at 90 mph but it never felt out of control.

Very true. A good boost controller can control the "hit" of the boost and can make it more linear and smooth. My boost controllers were pretty basic and couldn't control the wastegate like that.

 

[fdjizm]

Not quite.

First let me say that yes, a turbo will make more peak power (and torque) at the same boost as a centri. I love turbos, I've had several turbo cars, and they really do out-power (peak #'s) just about every power adder out there, boost for boost.

The only thing turbos don't have, which is what my "problem" with them is, is power under the curve. They're either on or off. You have virtually nothing under 3500 rpm for hp/tq. You're either waiting for boost, or you're spinning tires. There really isn't an "in-between."

Now, I'm running an F1C, wastegated. I see full boost (14lbs) by about 4500 rpm (results may vary depending on your target boost pressure and altitude). I have 6 lbs at 2500, and 9 lbs by 3500. The car PULLS from 1500. It's not tire spinning torque down low like a roots type blower, it's more linear and smooth. It doesn't hit like a turbo either.

However, because I'm spinning the blower that hard, at lower boost (14 lbs is low with a pullied down F1) it doesn't make killer numbers up top. My hp and torque really fall off around 6200, simply from the HP it takes to spin the blower that hard. But, if I run a larger pulley and slow the blower down, I lose more of the low end torque but gain my upper RPM power back. So I can "tune" my power band depending on which pulley I run, and peak boost is always the same based on my wastegate setting. This is mostly because I'm running a large, very capable blower. A D1 probably won't be as effective, at least at my altitude (5000 feet).

So, in the world of "this power adder is better than that power adder" I'm certainly not going to say one is better than the other as I beleive they all have their place. But I feel my setup is a NICE compromise between them all. Plus I get the pleasure of listening to that F1 sing at just about every RPM, especially idle.

Anyway, there's my .02.

My suggestion, decide what type of power-band you want, what hp number you're looking for, what type of driving/racing you're going to be doing the most, and then look at which power adder fits those needs the best. And maybe go for a ride in each if you can.

That sounds like my dream setup, shit I may be buying a wastegate! lol

 

[jodadejss06gt]

Why not get a nasty turbo and buy a really nice boost controller. I don't have any experience with controllers but I do know there are controllers that will adjust boost per gear. I'm sure you could play around with the settings and make the boost come on more linearly, maybe? Jeremy will your e2 do that?

Like cobra said you'd have more torque too!

 

[JeremyH]

Yes my power comes on alot smoother. I have played alot with the gate pressure and sensitivity on my eb2.

Also the billet wheel designs make boost off off idle and in 3rd and 4th gear i have full boost well before 3,000 rpms.

Check this out.

 

[jodadejss06gt]

Thanks jeremy! you have my peak torque at 3500 & power at 3900 = me :-(

 

[fdjizm]

Damn those billet wheels are serious!

 

[JeremyH]

Thanks jeremy! you have my peak torque at 3500 & power at 3900 = me :-(

Damn those billet wheels are serious!

Yeah this billet turbo doesnt mess around.

 

[19COBRA93]

Yes my power comes on alot smoother. I have played alot with the gate pressure and sensitivity on my eb2.

Also the billet wheel designs make boost off off idle and in 3rd and 4th gear i have full boost well before 3,000 rpms.

Check this out.

That's damn impressive right there. Thanks for posting, definitely learned a thing or two with this. In this case, I retract a lot of what I said I don't like about turbos.

 

[JeremyH]

You made a lot of good points cobra, and I do like the wastegated centri idea alot. But germeezy is right the newer designed impeller wheels are some highly, highly efficient setups. Precision, garret and bullseye have some nasty turbo's out there right now for our cars.

They make big turbo power with little turbo spool. And have a wider efficiency range. The compressor maps are impressive!

Look at turbopete, he has a 74mm billet turbo making almost 900 horsepower on a .81 ar housing thats spools very fast!

 

[jodadejss06gt]

I would have loved to see that curve with the .81 to see how much of that curve was the housing and how much was the billet wheel.

 

[JeremyH]

I would have loved to see that curve with the .81 to see how much of that curve was the housing and how much was the billet wheel.

None of the gains are from a housing change, The housing ar just determines intial spool rpm and in turn full spool rpm, it wont improve cfm or flow more at lower boost levels, that is controlled by the compressor wheels efficiency (map).

When I swapped from .96 to .81 There was almost no difference, like 100-200rpm faster spool, barely noticeable.

The billet wheel design is flowing more air(cfm)/more boost at lower impeller speeds(with less load/exhuast flow) causing large low-mid gains in flow/power, and more hp potential on the big end compared to a equally sized old version wheel.


The wheel on the hotside of the turbo hasn't changed, its the wheel on the compressor side that is a new/more efficient design.

 

[Germeezy3]

Hard to say really. At lower boost numbers the D1 will probably make more power. The harder you spin it though, the more the F1 will really shine. The D1 will be pretty maxed out at 20 psi, the F1 will have a LOT of room to grow beyond that, and will be more efficient at that level as well. Something also to consider, the D1 is 4.10:1 geared, and the F1's are 5.40:1 geared so boost comes on quick. They do take more HP to spin though which is why you'll see the real gains at the higher boost levels.



Very true. A good boost controller can control the "hit" of the boost and can make it more linear and smooth. My boost controllers were pretty basic and couldn't control the wastegate like that.

Thats why I asked the question I did because everything you said is definitely true about the old cast wheel journal bearing turbos.

Yeah this billet turbo doesnt mess around.

I can't even imagine what two smaller bb billet wheel turbos would do for boost response considering yours is already so good!

You made a lot of good points cobra, and I do like the wastegated centri idea alot. But germeezy is right the newer designed impeller wheels are some highly, highly efficient setups. Precision, garret and bullseye have some nasty turbo's out there right now for our cars.

They make big turbo power with little turbo spool. And have a wider efficiency range. The compressor maps are impressive!

Look at turbopete, he has a 74mm billet turbo making almost 900 horsepower on a .81 ar housing thats spools very fast!

Germeezy is never right... and one thing to keep in mind, I am sure you know this. But a twin setup with smaller turbos and billet wheels would have even better boost response. Also IIRC isn't your turbo not ball bearing which costs more but would make it spool even faster?

I would have loved to see that curve with the .81 to see how much of that curve was the housing and how much was the billet wheel.

The Billet wheels spool faster because they are lightweight compared to the cast wheels, but the main thing is a billet wheel allows wheel profiles that were too agressive to be cast. So your not only able to have a lighter wheel but also to optimize its profile for greater airflow.

Nothing beats the boost response of a smaller turbo and the flow of a much larger turbo!