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Tech Area => General Buick Tech => Topic started by: Scoobum on June 06 2013, 09:22:22 PM

Title: Single Pump-How Fast
Post by: Scoobum on June 06 2013, 09:22:22 PM
How fast can one go on a single pump? Alky is an SMC Progressive kit. Pump and hangar in the car are the latest from Racetronix. Hotwire kits for the pump and injectors...bo th again...from Racetronix. Injectors are 60's with alky...and testing at 28 PSI with the CEA 6262 the IDC is 68 percent...with zero KR. Have I got enuf "room" to make a 32 PSI pass?
Title: Re: Single Pump-How Fast
Post by: Steve Wood on June 06 2013, 09:27:02 PM
Dan,  and a few others, have eased into the nines with Razor's dual nozzle set up and a 340.

SMC does not put out nearly as much alky...so I am guessing maybe 10.4 or so.  I don't know what the compressor map says for that turbo and the ultimate result hinges upon that and what ic you are running...part icularly how much pressure drop it hangs on the turbo output

I would think you would want to keep the timing down
Title: Re: Single Pump-How Fast
Post by: Scoobum on June 06 2013, 09:40:40 PM
IC is a Gbody SLIC. I'm gonna hit Bison up as to where that turbo loses steam...and I think it's time to make a purchase from Julio.
Title: Re: Single Pump-How Fast
Post by: Scoobum on June 06 2013, 09:47:13 PM
Steve...any guesstimate as to 3rd gear timing at 30-32 PSI?
Title: Re: Single Pump-How Fast
Post by: Steve Wood on June 06 2013, 10:41:56 PM
well, alky tends to counter the compressor map some because it cools the charged air down quite a bit.  In the end, you have to look at the ic, the head porting and the cam.

Boost is a somewhat a meaningless number other than as it applies to your particular combo because as we simplistically say, boost is only the resistance to flow and it does not indicate how much air is actually being pumped into the cylinder.

I don't know how much timing it will take.  as you stuff more into the combustion chamber, it becomes a ticking time bomb that increasingly wants to blow up on its own and starting the timing earlier, just makes it more volatile.

If I were doing it without any prior experience, I would set third gear timing to something like 18 degs and start easing the boost up while watching for timing retard.  Definitely, I would use Powerlogger and I would bump the boost one pound at a time.

If I got to 32 psi (which sounds awfully high to me) and had not lifted the heads or blown anything up, then I might consider adding a little timing, but I don't think it would do any good...

If you had aluminum heads, the lousy thermal efficiency would allow you to get by with more boost and the increased flow would make far better use of the air at less boost.
Title: Re: Single Pump-How Fast
Post by: Scoobum on June 06 2013, 11:10:07 PM
All the reading I've done on the other board points towards lower 3rd gear timing at high boost. I ran 18 degrees back in early April, testing at 28 PSI. 32...mite be a bit generous. These are the same heads Norbs pounded 34 PSI through 8 years ago...so I know they flow well...and our cam profiles are fairly close.Norbs tuned a GN on the dyno a couple years back with an SMC progressive kit and a TT chip. It started showing KR around 500 WHP. His conclusion was the SMC kit couldn't keep up.
Title: Re: Single Pump-How Fast
Post by: PacecarTA on June 06 2013, 11:59:03 PM
you didnt get it
you state  because norbs pounded 34 pounds through them they must flow

this is not the case , the 34 psi is air that cant make it into the chamber

and theres more to it than just heads 
 


Title: Re: Single Pump-How Fast
Post by: Steve Wood on June 07 2013, 12:21:13 AM
X2
Title: Re: Single Pump-How Fast
Post by: motorhead on June 07 2013, 02:23:51 PM
Brad, more important than "boost pressure vs. timing" is: AFR vs. timing vs. octane (vs. EGT too if you want all the relevant details).

It has been a looooong time since I tuned a car with just a chip, so I can't recall if there is a fixed timing figure for any specific gear at WOT, or if it is curved.  The reason I say this is because there is a significant difference in cylinder pressure at Maximum Brake Torque (MBT) vs. redline horsepower; and the amount of timing you run at each point (and in between) is going to be different.  Consequently, 18* timing from MBT to redline is not necessarily ideal.  18* may be the tolerant figure for MBT, where 20* may be ideal at redline; and those 2* would be ramped in progressively – and would make more power safely.
Title: Re: Single Pump-How Fast
Post by: Scoobum on June 07 2013, 06:00:53 PM
you didnt get it
you state  because norbs pounded 34 pounds through them they must flow

this is not the case , the 34 psi is air that cant make it into the chamber

and theres more to it than just heads 
 





 
Okay, I went back and reread what Steve said...resista nce to flow...and you can't actually tell how much air is being pumped into the cylinder.
Title: Re: Single Pump-How Fast
Post by: Scoobum on June 07 2013, 06:28:35 PM
Brad, more important than "boost pressure vs. timing" is: AFR vs. timing vs. octane (vs. EGT too if you want all the relevant details).

It has been a looooong time since I tuned a car with just a chip, so I can't recall if there is a fixed timing figure for any specific gear at WOT, or if it is curved.  The reason I say this is because there is a significant difference in cylinder pressure at Maximum Brake Torque (MBT) vs. redline horsepower; and the amount of timing you run at each point (and in between) is going to be different.  Consequently, 18* timing from MBT to redline is not necessarily ideal.  18* may be the tolerant figure for MBT, where 20* may be ideal at redline; and those 2* would be ramped in progressively – and would make more power safely.

Mike...it's fixed in 3rd gear at 18 degrees. It's not showing any KR on PL...so I'm leaving it there.
Title: Re: Single Pump-How Fast
Post by: Steve Wood on June 07 2013, 09:59:13 PM
Cannot argue with the theory, but given the the limited rpm band we run, I have a lot of doubt that ramping the timing in third gear, or any other gear, would offer measurable benefit on our particular force aspiration cars

Title: Re: Single Pump-How Fast
Post by: Scoobum on June 07 2013, 11:02:07 PM
Thanks for the info/help guys. Steve...funny you should mention aluminum heads. I have Norbs' TA SE heads bolted to a freshened 109...with the 212/212 bumpstick you recommended.
Title: Re: Single Pump-How Fast
Post by: Steve Wood on June 08 2013, 12:19:05 AM
Remember that aluminum heads typically need more compression to make the same power as an iron headed engine (aluminum does not retain heat like iron).  On our engines, if we don't have the additional compression, it can hurt the power output-most noticeably on the bottom end.

We can get around that somewhat by running more timing in the lower gears to get some additional heat into the combustion chamber at launch and more boost on the top end.

If we were racing theory, we would run iron heads, but aluminum has some good qualities....s ave some weight, cheaper to cast in low volume numbers, and easier to repair.

Thinking about boost one more time-boost is a measurement of resistance to flow.  It's like a garden hose.  Turn it on full blast and water comes flowing out the end with only the resistance of the hose diameter/length and the flow input at the faucet to slow it down.  Put your thumb over the end of the hose and suddenly you feel a lot of pressure on your thumb and the volume passing your thumb takes a lot longer to fill a bucket even tho it will spray further from the end.

If we have a turbo and a stock intercooler and we run 25 psi on the boost gauge which is tapped into the plenum, but we would see 30-31 psi at the turbo outlet if we had a gauge plumbed there. 

Take a good intercooler with more volume and bigger in and out pipes and we might have to make only 26 at the turbo to get 25 in the plenum.  That would mean the turbo did a lot less work to get the 25 and the air would be a lot cooler.  Cooler is denser so we might actually get a lot more air molecules stuffed into the plenum than we did with the original ic that pushed the turbo side up to 30 psi which heated the air much more.

Now that we have air in the intake, we have to get it into the engine.  If we port the heads well then the heads don't cause as much resistance to the flow of air out of the plenum so we are opening the plug on the other end and we may see the boost drop a pound or two yet we are actually getting more air into the engine.  Bigger valves will help to let the air in...and/or a longer duration/higher lift cam that lets more air into the cylinder in a given time will do the same.  If the valves did not open at all, a small turbo could make a heck of a boost in the plenum...if we took the valves out of the heads, it might not make any boost.  I remember a friend of mine with a Stage engine about ten years ago that put a TA49 on it until he could get something bigger.  All he could get was 17 psi of boost with the wastegate closed.  The additional port side, valve size, and cubic inches was taking so much flow that the turbo could only generate that much back pressure.

These improvements may not be as obvious on a forced aspiration engine as it is on a conventional engine because there is a lot to be said for the power of a good turbo to force air past restrictions, but, it still makes it easier for the turbo to get its job done while keeping the air charge temperature down.

We have all seen a mild combination pick up a few tenths with a good set of heads...just  unplugs the circuit.

Where we get into problems is by screwing up the combo with a mismatched set of parts.  Put a big intercooler on the car with a small turbo and we lose velocity which hurts throttle response and may increase compressor surge at light throttle because the air velocity to the throttle body is lacking.   Compressor maps seem to have a lot to do with what turbo may stall out with a given combo and we can really screw up a driver with the wrong combo.  I went from a Craig 45 (T63E) that shook like a wet dog unless the pedal was pushed 3/4 down to a 66BB that has no surge at all....nothing else was changed.  Front Mount IC.

On my son's car, with a slic and a TE44, it went from no surge with a stock ic to some at light throttle with the slic.

The difference between the two was on the first car, it was impossible to drive thru the surge without completely lifting and then dropping the hammer whereas on my son's car, I can come down on the gas while it is surging and it will take off.

There is a lot I don't understand about the process.  I did make it better on the first car by leaning it out at part throttle...but it was no fun at the best.  I think it is just the nature of the compressor map-what rpm it stalls at and the steepness of the stall curve, but I really am guessing

On a race car, we can put a higher stall converter that makes the car slushy to drive, kills gas mileage and all around kills the fun.  I think race cars are easier to build because we just have to make it run well over 800-1000 rpm and we are not concerned how it runs if you drove it down the street.

I have seen more than one smart guy that went slower than guys who did not understand the theory but used the combinations of parts that worked for guys that were going fast. :D
Title: Re: Single Pump-How Fast
Post by: Scoobum on June 08 2013, 08:29:48 AM
Steve...thanks for taking the time to post that. You're getting good at dumbing things down for idiots like myself. I`m getting comfortable running 25 plus PSI...so those heads will see plenty of compression. Two other items I have bolted to this engine is a Champion stock appearing intake and a doghouse that`s been backfilled and has had a ton of porting and polishing done on the inside by my engine builder who also has a flow bench. Both will be going on the next engine. I get a ton of compressor surge at about half throttle...for tunately I don`t get into boost on the street. Is there any data out there comparing the Gbody SLIC to the Precision SLIC...or does anyone have any opinions on which one is more efficient.
Title: Re: Single Pump-How Fast
Post by: Steve Wood on June 08 2013, 09:13:08 AM
I have not seen any.  I recall from some time ago that the PTE had very low pressure drop across it with high volumes of air simulating a big turbo on the inlet side. 

Being cynical, I suspect most intercoolers are just clones of another.  People try to figure out how to make the biggest unit that will mount without much hassle on most cars and call it good.  The biggest science is in the design of the end tanks.  One is trying to get as even a flow as possible thru all the tubes in the core so we have to figure out how to distribute the air across the entire end of the core and get it to turn smoothly and flow at all points and that takes some science in the tank and inlet/outlet design.

Harry at PTE came out of Garrett just as did John Craig so I suspect he understands the theory and puts some effort into the thought of the design.  Other guys have simply said copy that and make it bigger, I am guessing.

In the end, most of these probably have the capability to flow a lot better than 98% of the customers will ever approach so it may be somewhat a moot point.

Dan was running an old V4, the same ic that I put on my son's car, and touched the Nines.  I guarantee that the PTC can flow more air.  Tony DeQuick did have a lot of professional experience in the business and he did make a damn good unit given the materials that were available to work with in those days.  If I recall correctly, he designed ic's and radiators for international harvester.

Point being that you will not be undergunned whichever way you go.  Norbs, on the other hand, will need at least four of the them to achieve his goals.  :D
Title: Re: Single Pump-How Fast
Post by: Scoobum on June 08 2013, 09:26:27 AM
I did a back to back to test with the Champion stock appearing intake and the Champion race intake. The bottom end torque suffered with the race intake. My take on it was the runners were so huge that the air velocity through them was slower. Your thots Steve.
Title: Re: Single Pump-How Fast
Post by: Steve Wood on June 08 2013, 09:41:21 AM
We are back to the waterhose example...A bigger hose will flow more water but it will flow it slower. 

Connect a fire hose to the faucet in your yard and water will flow out the end...very slowly.   Connect a half inch garden hose to same faucet and the water comes screaming out the other end.

In the old days, head porting tended to be aimed at total flow and it worked at high rpm but it sucked throughout the lower part of the band.  Ever see a tunnel port 429 Ford?  You could stick your head in the ports but the damn thing was a slug on the street because the air wandered around in the huge ports and did a lousy job of filling the the cylinders with air.

These days there is a lot of effort put toward maintaining air velocity throughout the rpm band rather than at just the top end.  Emphasis is put on where the material is removed from the port rather than just hogging it out all the way thru.

That's what happened with the Champion, it takes a lot of air to fill it up in order to get it moving.  No problem on a race car with a high stall converter, big turbo, and a cam that extends the rpm band...but it can suck on a driver because it kills low speed throttle response...jus t an extension of a giant intercooler.

Title: Re: Single Pump-How Fast
Post by: Scoobum on June 08 2013, 01:30:06 PM
Bison chimed in on the other board. That turbo is good for 28-30 PSI with good heads and a small roller cam. I've got several 28 PSI runs on PL saved...so I'll work from there. Should I go to a cooler 42 plug...or stay with the 43's? Gap?
Title: Re: Single Pump-How Fast
Post by: Steve Wood on June 08 2013, 01:55:42 PM
I will not hurt, but, I doubt it helps...sprayi ng alky keeps the charge pretty cool so it is not as likely to detonate, or so I think

I never had a problem running 42's on the street
Title: Re: Single Pump-How Fast
Post by: motorhead on June 08 2013, 03:02:01 PM
42s are good... should be in the same range as UR5s from NGK, IIRC.
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