450rwhp x2

David, what do you think 425-445 RWHP would = in a 5 speed?

550HP @ 14% drivetrain loss = 473
550HP @ 20% drivetrain loss = 440

Just a guess at losses. You probably have more than that, but Ira was on stock SC wheels with some aluminum in his drivetrain.

Micah,

For the sake of this discussion, lets assume the 5 speed has 15% loss and the automatic has 20%. Don't know if it's accurate, but I hear those numbers thrown around a lot. Lets also assume that Ira pulled 475 because Dave didn't detune it and I pulled 425 because I didn't try to over boost it and hit the knock sensor.

475 rwhp divided by .85 = 558.8 HP at the crank
425 rwhp divided by .80 = 531.2 HP at the crank

Lets take it a step further and figure another 5% loss for the unlocked converter.

425 rwhp divided by .75 = 566.6 HP at the crank

If you believe those drive train losses, 425 rwhp from an unlocked AOD looks very close to 475 rwhp from a 5 speed. That would be nice and comforting for some people, but I guess I'm just have difficulty believing that the unlocked AOD is consuming 10% more power than a 5 speed.

David
 
Micah,

For the sake of this discussion, lets assume the 5 speed has 15% loss and the automatic has 20%. Don't know if it's accurate, but I hear those numbers thrown around a lot. Lets also assume that Ira pulled 475 because Dave didn't detune it and I pulled 425 because I didn't try to over boost it and hit the knock sensor.

475 rwhp divided by .85 = 558.8 HP at the crank
425 rwhp divided by .80 = 531.2 HP at the crank

Lets take it a step further and figure another 5% loss for the unlocked converter.

425 rwhp divided by .75 = 566.6 HP at the crank

If you believe those drive train losses, 425 rwhp from an unlocked AOD looks very close to 475 rwhp from a 5 speed. That would be nice and comforting for some people, but I guess I'm just have difficulty believing that the unlocked AOD is consuming 10% more power than a 5 speed.

David

I believe the 10% difference easily. Does your car run 10% faster than Ira's? I'm putting a 5spd in mine, after I get it swapped I'll dyno it and tell you the % difference.
 
Now dont shoot me for saying this. Stock rings be it 130,000 or 255,000...Stock internals with only a bearing change. The reuse of the stock balancer. Sounds like a hand grenade waiting to go off.

Damon,

The balancer can be inspected. If it hasn't broken down, it should be functional. If you pull it off and check the fit before installing it to ensure it will still be an interference fit, it should be fine. That is the only part I'd worry about.

When I pulled my 93 motor apart (160k miles) rings were fine, pistons were fine, rods were fine, and crank was serviceable. The bores still had factory cross hatching, and cylinder bore out of round was very low to almost being none. The only real problem where the main and rod bearings. Both showed considerable wear. They could have gone longer, but one of the main bearings was close to creating some real issues on the crank.

Considering the tuning capabilities and understanding that have matured for our cars if we keep detonation out of the loop, the stock pistons and rods are completely workable for significantly higher HP levels than stock. In the past I was concerned with power over 400rwhp with stock internals. From what I have seen over the past 3-4 years, I don't feel that way anymore.

Note on the fastener issue you describe, RPM's are still very low on these motors and well within the piston velocity numbers of a stock motor. With this type of power you may be hitting the outside specs of the stocker RPM range, but it's still workable.
 
I can't emphasize combination enough. Ira's car made 260rwhp when Brian Herron put it together. That was after tuning by Jerry W, the AR, FMIC, cam, and Borla exhaust. Not numbers to get excited about by any means.

The first think we did with his car a couple years ago was diagnose some issues the car had - boost leaks being one of them. After fixing this the car made about 16 or so psi but the boost curve was lazy so I told him that he needed to improve the exhaust and increase the OD.

So Ira replaced the y-pipe and added 5% OD and after tuning the car responded with 345rwhp @ 21psi. Even at this point the car was very fast (12.76 @ 107mph) but the excessive boost was troubling me.

Ira decided to go with ported heads and so I told him right then he would also have to improve the exhaust even further and open up the intake as well. We made plans to do so.

I made several cam selections before settling on the one he finally has and the cylinder heads also went through several renditions before I was happy with them. In the end the car is running another 5% OD but making no more boost (20psi).

Some key points: The AR likes to run around 20psi. An Eaton, not so much so. They'll do it but there is a lot more heat involved.

In the case of Ira's car, we have always run a lot of boost. When it was only making 16psi it was a dog. We ran 20psi through the stock heads and we are running 20psi now.

Ken, your car has never made enough boost. Even back when I first tuned it I believe it was only making about 12-13psi on the stock motor. It was only when you first put the M112 on that it actually made respectable boost numbers. It's too bad it blew up because I think the car would have been totally different if it were properly tuned on the stock motor.

I'm also not trying to say anyone is to blame, but you've been chasing HP when you had mechanical issues with your EEC and/or ignition. It's too bad no one caught that earlier, it would have saved you a lot of time and frustration.

At this point I still believe that there is a whole lot of power waiting to get out but it's going to take some time to find it. My suggestion is to work things out until all issues have been totally resolved and then work at increasing boost until you have 19-20psi again.

And yes, I do believe that Ira's heads/cam package has a lot to do with his results.

I pretty much agreed with your accessment Dave. The car has never made good power from the mods I added and it has been disappointing. :(Im sure if I can get the electrical and or mechanical problems sorted out the car should make good power. In the past I just kept modding the crap out of it hoping to see some big numbers. Im sure that I and a whole lot of others are thinking how much we want Ira's numbers and Ira's mods and be top dogs. Right now I would be doing back flips if I had ricardos numbers from his hybred. I'll just keep working on solving the riddles in my car. Get that done, find another 100 missing ponies, some drag radials, and I can go looking for CMac89:D

Ken
 
David, I already said what I feel you should change. ;)

Mark, Ira's car went slow. 12.60's @ 110mph. However, being that it is a 5spd and Ira has little experience behind the wheel I don't put much stock in those times. For example, I drove a car for someone else at the Shootout this year and first pass ran 14.0 @ 100mph. The owner ran mid 15's @ under 90mph. Yes, driver makes that much difference in a 5spd. Another issue is that traction becomes non-existent and launch is difficult with almost 480 ftlbs torque. Hopefully at some point someone will put a motor like this in a real race ready car and show what it is capable of. For now all I can do is build the power.

Damon, I listened to you guys with my last "450" rwhp motor. I got scared and took it apart only to find that it was in better condition than most stockers with the same mileage that I tear down. I've seen bent connecting rods and broken pistons from 250rwhp motors plenty of times. It's not the power thats breaking stuff, it's abuse. Anyway, this is not a serious racing motor. This is a completely streetable and emissions friendly driver that will be fun to drive and still get over 20 mpg with ease.

Thinking that rod bolts are going to come apart simply shows a lack of understanding of the physics that goes on in a forced induction motor. A forced induction motor actually puts significantly less stress (about 40% according to some estimates) on the rotating assembly than an NA motor would at the same power level. Add to that the fact that this motor "gets er done" before 6000rpm and you have a decent recipe for success.

Ira is aware of the risks of running the stock rotating assembly at this power level and is willing to live with that. Seriously, even if it did go "boom" these aren't $3000 super hi-tech one-off heads we are talking about. They don't even cost 1/2 that. The heads themselves aren't really even the secret. It's the combination that is key.

Julian/David, I have dyno'd the same car with the converter locked and unlocked and I have observed between 10 and 13rwhp difference on the same car at the 375-390rwhp level so that puts it at less than 5% from locked to unlocked. AS for auto to 5spd comparisons it would be hard to accurately guess but I think the power difference between Ira's motor and David's is insignificant.
 
Micah,

For the sake of this discussion, lets assume the 5 speed has 15% loss and the automatic has 20%. Don't know if it's accurate, but I hear those numbers thrown around a lot. Lets also assume that Ira pulled 475 because Dave didn't detune it and I pulled 425 because I didn't try to over boost it and hit the knock sensor.

475 rwhp divided by .85 = 558.8 HP at the crank
425 rwhp divided by .80 = 531.2 HP at the crank

Lets take it a step further and figure another 5% loss for the unlocked converter.

425 rwhp divided by .75 = 566.6 HP at the crank

If you believe those drive train losses, 425 rwhp from an unlocked AOD looks very close to 475 rwhp from a 5 speed. That would be nice and comforting for some people, but I guess I'm just have difficulty believing that the unlocked AOD is consuming 10% more power than a 5 speed.

David


I would bet that you lose a lot through the drivetrain.
575 x .74 = 425.5 My guess for you
575 x .83 = 477 My guess for you with a 5-speed
I've always used a 26% loss on a an auto and 17% on a 5-speed

Amazing how much power you lose through the drivetrain and how large the difference becomes once you get that much power. Sounds like you still have room for improvement also.
 
Last edited:
Those drivetrain loss numbers are a little off of the chain. First of all an engine dyno is not "0" percent.

There's about 30-40lbs (depending on type of dyno) of rotating mass that is hooked to the back of the motor. An engine dyno puts way more load on the motor than a chassis dyno does. This is part of the reason they do inertia chassis dyno's.

This is why most sophisticated aftermarket transmission and rear end companies account their products for 10% drivetrain loss. But there aren't many cars that have IRS.

Now I'm not saying that there isn't a decent loss, but just not numbers that big. It really depends on the converter you have and I know it's not exactly an 8" with a high speed lock up.
 
Well I wish for the best. I'm aware of the limitations of the factory componants due to engineering tolerences and manufacturing processes. I do not nor does anyone here I believe knows exactly what it will take to destroy any one of these componants under the power of even a well tuned machine. Add some bad gas, a hot day humid day, a malfunctioning dodad and who knows.

I consider myself thr king of being cheap at times. My turbo cougar has a stock bottom end in it be it balanced, ARP hardwared and girdled. Sur eit runs, made great power and hadnt broken when I actually drove and beat on it. But heck I know its a matter of time. I know Ira likes to race his car so maybe this will be a perfect test of just how well a stock motor can handle this kind of power.

My hats off to you Dave for making some great numbers and to Ira for using half of it getting down the big end haha!
 
Man those are awesome #'s.Just think with the drivetrain losses and the power it takes to turn the blower both Dave and Ira's motors are putting out deep in the 600 maybe low 700 horse range prior to the blower and drivetrains sucking up the horsepower required to turn them.Or do the a/r's require less h/p to turn than an m90?


Jay
 
Dave D,

What kind of mods if any were done to the fuel rail? Also can you PM some info on the dual alcohol inj setup. I'm most likely going to need something like that for my setup.

Another point maybe to note is Ira's car is a 95 which has a better Rod/Piston setup via a floating pin as compared to 89-93 years. Like Dalke has said Ive also seen bent rods from stock setups. When I took my Annv car apart for the first time two rods were bent. Also, an H-Beam rod doesn't weigh any less than a stock rod from what I recall.

Chris

Edited for Clarity
 
Last edited:
Micah,

For the sake of this discussion, lets assume the 5 speed has 15% loss and the automatic has 20%. Don't know if it's accurate, but I hear those numbers thrown around a lot. Lets also assume that Ira pulled 475 because Dave didn't detune it and I pulled 425 because I didn't try to over boost it and hit the knock sensor.

475 rwhp divided by .85 = 558.8 HP at the crank
425 rwhp divided by .80 = 531.2 HP at the crank

Lets take it a step further and figure another 5% loss for the unlocked converter.

425 rwhp divided by .75 = 566.6 HP at the crank

If you believe those drive train losses, 425 rwhp from an unlocked AOD looks very close to 475 rwhp from a 5 speed. That would be nice and comforting for some people, but I guess I'm just have difficulty believing that the unlocked AOD is consuming 10% more power than a 5 speed.

David

David, the owner of KVR is marketing a new lightweight rotor that he claims added 1% more HP (dyno proven) on his own n/a Cobra. At the kind of power level we are talking about, that would be an extra 4.5 RWHP just from lightweight rotors. So don't discount the weight difference from your wheels to Ira's stockers. It is a factor.

Further, remember that we are talking percentages. The higher the numbers...the bigger the difference is going to be. When we were stuck in the mid-low 300 RWHP range the difference may not have show up as much as the 450RWHP range.......or the 550 RWHP range.

BTW, I beleive Ira was making 22 psi (I also though he already had an alum. flywheel, but I digress....) so remember what psi you were making at that 425 RWHP level. Also, his rotating assembly undoubtedly is more efficient than yours :) I think the numbers all shake down...if anything I think it shows that your custom intake gaskets aren't really worth the work, but who knew at the time?

Another PS....how much HP do think the more durable BHJ balancer is costing you!!! I know that thing weighs a lot.
 
Last edited:
I believe it takes less HP to spin an AR to 20psi then an M90.

I think the weight savings on the assymbly is in the rob/piston combo with less weight being on the small end/piston side of the rod. If anything I;d think youde have a tad bit more weight at the crank side. Its been awhile but thats what I recall
 
David, the owner of KVR is marketing a new lightweight rotor that he claims added 1% more HP (dyno proven) on his own n/a Cobra. At the kind of power level we are talking about, that would be an extra 4.5 RWHP just from lightweight rotors. So don't discount the weight difference from your wheels to Ira's stockers. It is a factor.

Further, remember that we are talking percentages. The higher the numbers...the bigger the difference is going to be. When we were stuck in the mid-low 300 RWHP range the difference may not have show up as much as the 450RWHP range.......or the 550 RWHP range.

BTW, I beleive Ira was making 22 psi (I also though he already had an alum. flywheel, but I digress....) so remember what psi you were making at that 425 RWHP level. Also, his rotating assembly undoubtedly is more efficient than yours :) I think the numbers all shake down...if anything I think it shows that your custom intake gaskets aren't really worth the work, but who knew at the time?

Another PS....how much HP do think the more durable BHJ balancer is costing you!!! I know that thing weighs a lot.


Micah,

I think I'm making nearly the same power at the crank as Ira, and what I'm trying to determine is how much more power I'm leaving on the table if any. Yeah the added weight of the BHJ is probably costing as much as I saved by using the aluminum underdrives.

Dave's comments on the exhaust are of particular intest to me, because I've been trying to decide if I should add v-band connections to my mid length headers (ball and socket starts leaking everytime I race or dyno) or replace them with long tube headers.

Then I need to decide if I should get a larger resonator and a 3.5" mid pipe and use the 2.5" mufflers I've got, or get some Borlas, or delete the resonator, or upgrade to a later model gas tank and run true duals ect...ect..

David

PS: Dave, is one of the meth injection nozzels on Ira's car located before the blower inlet or are they both located after the intercooler like my turbo car ?
 
Don't even think about revising the exhaust with that old tank. You'll cry when you see how much more "straight through" the new style is. Also, if I COULD have used a 3.5 inch mid section I would have, but everyone around here likes to bend up to only 3 inch.
 
Dave D,

What kind of mods if any were done to the fuel rail? Also can you PM some info on the dual alcohol inj setup. I'm most likely going to need something like that for my setup.

Another point maybe to note is Ira's car is a 95 which has a better Rod/Piston setup via a floating pin as compared to 89-93 years. Like Dalke has said Ive also seen bent rods from stock setups. When I took my Annv car apart for the first time two rods were bent. Also, an H-Beam rod doesn't weigh any less than a stock rod from what I recall.

Chris

Edited for Clarity


Ira's motor is an 89 motor so not only does it have pressed pins but it doesn't have a windage tray either. The dual nozzle system sprays a small shot in front of the blower and a bigger one after. You really can't use that setup on a turbo so I don't think it would be of much interest to you. In your case a single nozzle should work fine.

The fuel rail is stock other than the modification to clear the AR as are all the lines to the motor. This car has is a 255lph FI fuel pump and 60lb injectorswith a stock regulator.

The motor made 19-20psi depending on load and air conditions, according to my datalogger.

I think the 3.8L is a lot stronger than a 5.0. I don't think Ira has anything to worry about moreso than anyone else.
 
So i'm wrong on the boost too. But here is something I am right about. A friend of mine made 498 RWHP out of a T-5 302 with TrickFlow heads and a Vortech with a LOT of boost. And that car survived.
 
David, if you are going to upgrade to a newer model tank, I will be going to a cell soon. If you are interested in my tank, let me know.

Chris
 
Ira, congrats on those amazing numbers! :D You've certainly come a long way in what seems like a fairly short period of time. It's great to see what an AR equipped SC has the potential to put out. I think you went about building this powerplant intelligently by letting a knowledgeable and dedicated engine builder guide you.

Oh, and congrats to said engine builder for putting together such a great combo without actually building an engine on this one!
 
Micah,

The eventual failure will most likely be a split block (right down the middle) or twisting the snout on the crank. Ive done both. Stock blocks even bottom ends will survive awhile...But like anything they have thier limitations survive. Both blew with between 450-500rwhp..My turbo motor survives as well and its making 748rwhp..But I never abused it.

It be interesting though to see how it holds up
 
Micah,

The eventual failure will most likely be a split block (right down the middle) or twisting the snout on the crank. Ive done both. Stock blocks even bottom ends will survive awhile...But like anything they have thier limitations survive. Both blew with between 450-500rwhp..My turbo motor survives as well and its making 748rwhp..But I never abused it.

It be interesting though to see how it holds up

Well aren't you just the penultimate optimist today. :rolleyes:

Ira
 
Back
Top