The Dilemma , Horse Power or Streetability

[Bob Holmes]

The reason that I asked about your NA power curve (which you never answered) was that you can use the NA bottom end while waiting for the turbo to spool up. That way you may keep from blowing away your tires and breaking drivetrain parts, while giving you the ability to make high end power.

I'm glad to see that we are no longer talking about a 10,000 rpm redline, now were at least down to 8,000. Which is still too high. Turbo cars at LeMan try to redline under 7,000, so should you. Let the turbo do the work. You should look at the turbo starting to boost around 2500 to 3,000 and give it 1,500 to 2,000 rpm to build to max boost. Try and drive a turbo car that goes from zero to full boost in 1,000 rpm, oh and also make sure you can open track it, LSR it, drag race it, street it, and have it wash your clothes.

Here's a secret to using the calculator, and the BorgWarner one is a great teacher, don't force it to do what you want, have it lead you to a real answer.

[TC]

Alex, I've stepped away from your build because I've thought that it was unrealistic and an example of the Stroker McGurk syndrome.

Right now you're a monkey ####ing a football. (of course that's only my opinion, and you may like monkeys ####ing footballs)

When you've read some of the texts on turbos, can look at a map and realize that you're off the surge line and have an unrealistic boost curve and come down to earth then I think that progress can be made on looking at turbos. Presenting yourself as an expert and making the assertions that you do is off-putting. And its downright dangerous because folks casually looking at this site might actually believe what you're saying.

It'd be nice if you actually said "I don't know what the hell I'm doing, would someone give me a hand."

Start here:

http://www.turbobygarrett.com/turbobygarrett/tech_center/tech_center.html

Here's a great one:

http://www.turbodriven.com/performan...6_wrsin=92044&

I've been researching this stuff for months, and those sites were some the first I visited.......What I see here is a lot of people saying I don't know what I'm talking about, but don't feel they need to add their knowledge, just their negative input........If you see something wrong with what I'm doing, why don't you simply point it out and tell me which pair of Turbo's to use, I mean that's what I've been looking for for the last 6 months in the first place, but after doing some research, I'm starting to think that People don't give a rats ass about how the turbo works, just that it gets them their "Peak" power number to brag about........My '88 T-bird after I by-passed the wastegate controller would have full boost(18psi) by 1800rpm and pull that all the way to redline......So don't tell me you can't have max boost at a low rpm and keep it into the higher rpms, cause I have a car that proves you wrong........

From what I have read if I'm on the right side of the surge line, then I will be making boost, the variable asks what rpm you want max boost at, that point on the T61 map puts it just on the right side of the surge line, not to mention if I get a Ported housing(anti-surge housing) it will move that line a little further to the left and I can get full boost at an even lower rpm......granted I do know that the exhaust A/R's will have a bit to do in this.....which is probably what I'll discuss with the experts before buying my turbo's............But for know for the Turbos that seem to meet my specifications the T61's seem to fit the bill.............

[dieselgeek]

If you see something wrong with what I'm doing, why don't you simply point it out and tell me which pair of Turbo's to use

What you're doing wrong is pretending a person can build an engine with a pre-stated Brake Specific Fuel Consumption. Unless you just got done designing a few decades' worth of Formula One engines, GTFO with that notion. You build the best you know how, THEN you test it and report the numbers. You're an Engine Builder, certainly you've dyno'd engines that you've built, right?

My '88 T-bird after I by-passed the wastegate controller would have full boost(18psi) by 1800rpm and pull that all the way to redline......

Bob will probably tree me on the "NO, IT WON'T" but just in case.

[Beagle]

without putting too fine a point on it, this is what I was responding to - from your original post:

"
Anyway what would you do, go with the smaller turbos that will get me close to my goal and have a car with decent street manners or go for the bigger turbos that will get me to my goal of 1200hp but at a sacrifice to low end boost and power??........."

and I responded that I would go smaller turbos, less cam, keep it further away from surge. Bob had a good point about not wanting it to go from 0 to 15 in 1000 RPM... let's keep the tires under it. Again, thinking out loud here.

[TC]

The reason that I asked about your NA power curve (which you never answered) was that you can use the NA bottom end while waiting for the turbo to spool up. That way you may keep from blowing away your tires and breaking drivetrain parts, while giving you the ability to make high end power.

I'm glad to see that we are no longer talking about a 10,000 rpm redline, now were at least down to 8,000. Which is still too high. Turbo cars at LeMan try to redline under 7,000, so should you. Let the turbo do the work. You should look at the turbo starting to boost around 2500 to 3,000 and give it 1,500 to 2,000 rpm to build to max boost. Try and drive a turbo car that goes from zero to full boost in 1,000 rpm, oh and also make sure you can open track it, LSR it, drag race it, street it, and have it wash your clothes.

Here's a secret to using the calculator, and the BorgWarner one is a great teacher, don't force it to do what you want, have it lead you to a real answer.

Isn't the amount of boost a turbo makes relative to throttle position?? Plus I can tune down the wastegate controllers and make 700hp with 6lbs of boost and not be working the turbo's at all........

As for a powercurve I don't have a desktop dyno anymore that works on my comp, so that I could simulate one, that is why I posted the cam I am eyeing, the power range stated was form 3200-7200........I do plan on running 9:1 compression so the times that the car isn't being boosted it'll have a little more power......

[dieselgeek]

Isn't the amount of boost a turbo makes relative to throttle position??

Not at the level of power you're looking to make. Lots of guys at that level resort to major trickery to be able to manage boost on a turbo that's nearing "too big"

I have a couple customers that run a boost controller that's based on TPS position for exactly the reason that the throttle does not modulate power to the wheels in a big boost situation. If you get them to spool, the throttle is an on/off switch. This is why you might consider a Procharger - because the big turbo engine is going to suck balls when it blows off the tires in the first 8 feet, then you let off and are back to 400hp NA which will be all out of whack because the suspension expects 1200hp.... argh. if you ever get to this level, I hope this post is archived for you to read; you will say some pretty funny things about yourself. I guarantee it.

[TC]

/edit 2 - keep the compression, use a smaller cam, screw it. Test out that bad boy crank for pressure... Use windshield washer fluid under boost. FTW.

Now your starting to think like I do.........

[TC]

Not at the level of power you're looking to make. Lots of guys at that level resort to major trickery to be able to manage boost on a turbo that's nearing "too big"

I have a couple customers that run a boost controller that's based on TPS position for exactly the reason that the throttle does not modulate power to the wheels in a big boost situation. If you get them to spool, the throttle is an on/off switch. This is why you might consider a Procharger - because the big turbo engine is going to suck balls when it blows off the tires in the first 8 feet, then you let off and are back to 400hp NA which will be all out of whack because the suspension expects 1200hp.... argh. if you ever get to this level, I hope this post is archived for you to read; you will say some pretty funny things about yourself. I guarantee it.

You don't really believe that just because I'll have max boost at 3000rpm that the motor will make 1200hp at that point do you?? Turbo motors have power curves and peak numbers just like naturally aspirated motors do..........

[SuperBuickGuy]

Bob mentioned borgwarner - here's the site

http://www.turbodriven.com/en/performanceturbos/matchbot.aspx?a=1

[Bob Holmes]

Build it, TC, you already have all the answers. And since I don't think like you do, I'm eagerly waiting to be schooled.

[TC]

Build it, TC, you already have all the answers. And since I don't think like you do, I'm eagerly waiting to be schooled.

If I had all the answers I wouldn't be debating this with you guys..... DG made a good point that having the boost come on to soon can blow the tires off the car, that has me thinking........I mean I want instant power, but I have to think about what that can do when going to pass someone on the road and having the car downshift, I know even on my '99 camaro things can get squirrelly........ So maybe stepping up to a bigger turbo might be a better option.......Turbonetics with their Turbo Matrix that's basically a table that sizes turbo's by displacement and horsepower recommends a T66 for what I want to do.....I plotted that out on the Squirrel Calculator and it's pretty close to the T61 but max boost wouldn't come in until 4500rpm, here's that map....


So do you think this would be a better fit, I do like how the higher rpm points all fall in the highest efficiency island of the table.......

[JeffMcKC]

Its not really a debate. It seems like a simple phone call would take care of it.

[A/Fuel]

Why don't you just put a turbo on that white camaro of yours and get a little Honda for put-putting around town? It would seem to me that the camaro would do just about all the stuff you want with minimal up grades, then you could get busy on the other camaro.
Just think....you would have two projects done, have a little more experience with turbos, and then you could start building a Monte-Carlo thats rattleing around in your head.

[SuperBuickGuy]

why don't you just....? that seems a bit overthetop. Isn't that kind of like telling someone to just stop racing and get a real job fishing?

[TC]

Why don't you just put a turbo on that white camaro of yours and get a little Honda for put-putting around town? It would seem to me that the camaro would do just about all the stuff you want with minimal up grades, then you could get busy on the other camaro.
Just think....you would have two projects done, have a little more experience with turbos, and then you could start building a Monte-Carlo thats rattleing around in your head.

A F'n Honda, are you serious??!!!! I wouldn't be caught dead driving a Honda or at that any Asian car.......

The white camaro is actually done, though I'm going to treat it to a cam swap this winter, which should boost HP up to about 500hp(dyno proven) and get me into the 11 second quarter mile range..... I will still keep it as my daily driver, because hey everyone should be driving around in a 500hp daily driver in my book.....

And the next vehicle on the chopping block to get done is my '71 GMC, then I'll get on the old Camaro........though in the mean time I plan on putting this twin turbo engine together, put it this way I'm only a block and set of pistons away from starting the build........ As for tuning the blow-thru setup, I have a few friends that can help me with that, my friend Jimmy has an 8 second Mustang with a blow-thru setup(Procharger), also the place he works has built may cars that run 8's with blow-thru setups....though some were turbo cars, most are using Prochargers.......But I'm sure the tuning aspect of both are similar........Plus I'm going to be sharing the build on here, and hopefully my experiences, successes, and failures will help the next guy that is in my shoes in building his own twin turbo project a little more easily.......

Put it this way, I'm going to do what I'm going to do, if I fail miserably, then I fail miserably, but at least I did something I wanted to do.......

I appreciate everyone's input on this(thank you), I know I can be pig heads at times, but what you guys say does sink in over time....... And that is why I like Bench Racing this stuff with you.......