Dern lackaboost

[EightSecV6]

Increasing A/R will definately decrease back pressure, there is a fine line when determining compressor size, turbine size, and A/R as well. I personally dont run anything past 25# usually but in some situations I have .
Chris, I absolutely think your problem can be solved with the wastegate tension.
Reg, I am not very familiar with the Turbonetics exh. wheel but I would think an exh hsg change is in order, your engine could easily benefit from a .96 hsg, especially with the supposed fast spool of the BB center section. These are just my opinions on some of the stuff we've run into problems with over the years. I cannot however comment good or bad on the TNetics turbos as I have NO experience with them at all, maybe you could question them about it?
Good Luck,
Bill

 

[ChrisCairns]

***Did the mystery guy in Las Vegas say the increasing the A/R would decrease backpressure or is the only solution getting one of those monstrous PTE 88 housings***

We never discussed the A/R that much.....his whole point was that instead of going to a larger compressor wheel people should be going to a larger exhaust housing. A la PTE's biggun.

I would think though that a larger A/R would help lower back pressure considerably.

When J.C. originally built my 76 he sent it with a housing with an A/R of 1.14. Plus he included a .96 housing. I didn't like the idea of that 1.14 A/R so I switched housings before I tried the 1.14 one. I thought it would negatively affect my spool up. Wish I had tried it though.

 

[ChrisCairns]

Guess we were posting at the same time Bill.

I looked at my Turbonetic springs. I have them all....except the black one....lol.

I'll be getting one. Although I'd like to wait until I hear how Reg does with his dual spring experiment.

 

[JCotton]

Hmmmm, not usually up this late, but I think I ate too much, too late..... had a nightmare and here I am!! Interesting stuff here. Couple points I'd like to make, Turbonetics does have a dual spring set up, I will be having one shipped to Reg. Monday. But, as I spoke with reg in depth this week, several times, I believe he has more than just a boost issue, just not sure where to begin to find it, from here. He has been running 19-20lbs with several different turbos the last 6 moonths, with a definite loss of power, 20lbs of boost on a 272 motor with his current set up should easily net a very low 10 second pass, or at worst make at least 130 to 134 mph. So even if we get him 25-28lbs of boost, I would have to say there is something wrong. I've run 9.70's@136 with a ball bearing 76 on 21lbs of boost, of course that was after Billy A. gave me one of those super used pistons from his old motor after I had melted one. I also must say, that was off the foot brake, with a BB turbo that spooled so fast, I could actually cut a lite back then. I could bang out 15lbs of boost in under 2 seconds! Lotta red lites back then too. Back to the lack of boost now, providing everything is right, no exh leaks, good convertor, good DFI program, etc. the spring should take care of it. One last point, Reg also runs a DFI with 18 degrees of timing, most of us are running FAST systems with 24 and up of timing. Timing does make a differance, just wondering how much differance it would make with the DFI so low. Maybe Bill can jump in here as I think you may have more experience with the DFI than I do. If the timing is low at WOT, where is it on spool up?

 

[EightSecV6]

As far as the DFI goes, I personally have found them to be about 4 degrees different. For example if you are running 18 on a DFI, the FAST system would be 22 for the same tune up using 10deg as the reference. It has something to do with the reference signal on the DFI.
I agrre Jack, the car obviously has some other issues, I have never needed anyhting more than the black spring in a single racegate to get the boost where I want it ,but again, I dont like to run more than 25# or so, I run my compression and timing a little higher than others but that is what has reliably worked for me.. Maybe its back pressure, maybe its not. If you turn the boost up 6-7# and have a marginal gain, I would say it is back pressure related, could be compounded by an improperly ground cam or valve timing. On a 272, with a .81 hsg it should spool relatively fast with a BB or not. Please post the results from your testing.
Bill

 

[Reginald West]

Ok guys Jack Cotton is going to die laughing at this because he thinks I am the worlds most snake bitten guy.I got the truck loaded up and put the trailer behind it. Ready to put the car on and head for the track.I noticed that one of the axles on the trailer looked cocked to one side. I looked under the trailer and saw that the shackle that holds the leaf spring and the axle to the trailer was broken loose.Needless to say I was not going to put my car on the trailer untill I got that welded back in place.So my day at the track was shoot in the butt.

I will try out the 2 springs when I get them and let you guys know about the boost problem but in the mean time I think you guys are right about the back pressure.I will be talking to jack tomarrow about maybe going with a bigger A/R housing.If I ever get the boost up I want to try to take the timing up 1 degree at a time untill the car won't go any faster and then back it off about 2 degrees.This thing is going to run a 9.90 if I have to carry it down the track.

REG

 

[ChrisCairns]

Sorry to hear about that Reg. (Mind you, a real man would have just used some J.B. Weld....lol.)

And once we get snow up here don't you even THINK about posting about going to the track in sunny CA. The jealousy would kill me.

 

[Chuck Leeper]

Turbos, etc

A couple comments from the old dummy hillbilly...
Reg says:

This thing is going to run a 9.90 if I have to carry it down the track.

REG
__________________
87 GN Stage 2 10.02 139 mph

Looking at my "mystery chart", there is question that comes to mind.
A trap speed of 139mph indicates the HP necessary to run a 9.70 et, IF the other measured points on the run are met.
IE: 139mph should produce, [close to] the following:
Et=9.70, 1/8=6.12, 330'=3.90, 60'=1.33.
If the car is not performing close to these numbers, then the comment by Bill that boost over about 25 psi may not be necessary, holds true.
I don't see the other numbers in the signature, but would think that working improvements in areas other than more boost would provide that elusive 9.90 and then some.

In the FWIW dept:
There was a thread some time ago on the DFI vs FAST timing. I think Craig responded and the reply was pretty much the same as Bill stated.. 4*..

My old dog goes 133 @3680#. Done that w/ both a T-70 P trim and an .82 AR and w/ a T-72BB P trim, .82.. Both at less than 23psi. ET ain't so great!! Guess I need to "work" on other areas too!!



Back under my rock...

 

[Reginald West]

Boost

Ok I got in a little track time last night before we got rained out.I put the 2 springs in the wastegate and the boost did go up to about 25 lbs.I still had a little more adjust left in the wastegate controler.The car went faster but it just hit a wall we added timing,we leaned it out (exhaust gas temp 1650) nothing effected the car it ran 10.80 128 time after time.The 60 foots were in the high 1.6s the 1/8 mile was 103 mph et 7.0.

Bottom line guys is that 2 springs will work in the wastegate and bring up the boost.As you can see I still have a few other issues to work on.Bill I am going to look into changing that exhaust housing on the turbo like you suggested. Any more ideals out there? I am open to any and all.



REG

 

[ChrisCairns]

Re: Boost

Phone John and ask to borrow a housing. I'm sure he'll do it on an exchange basis and a "I'll buy it if it works" type promise. He's that way.

Thanks for the info on the springs. How did you get them into the cups? Slide the springs together, then the top of one spring goes into the top cup and the bottom of the other spring goes into the bottom cup?? And what stops the springs from sliding back apart?

 

[Reginald West]

Chris
The new spring was small enough to fit inside the other spring, so the orginal spring held the new one in place.

REG

 

[JCotton]

Reg,

Good to see you gain some boost back, but as I said before, no doubt, you have something else going on. Don't waste your time with the housing, 25lbs of boost with your combo should have gotten you at least a 9.70 at around 136-139mph. A housing may help you in the back pressure department, but it will not give you 10 mph back! Thats the bottom line. You have to look somewhere else for the lost mph. I wish I was closer to you, I'm sure we could find the lost MPH. You have to go over the other changes you have made since you ran 139, I believe there in lies your problem. Possibly weak valve springs? Hows your RPM range, are you able to pull good RPM? I just had a car in that I was ready to pull the new motor out of, it was so down on power. I decided to pull the PSide header off since it had a small crack we could see, found the header to have major cracks, once we got it off, all over the place. The turbo flange was about to fall off! We welded the header back up and at the same 15lbs of boost the car is complete animal. In other words, at 15lbs of boost before the header repair, a stocker could have beat it, after the repair, the car is a definite 10 second runner.
One last thing, didn't you tell me you took my exh. housing off and put a different on? If it was smaller than the .81 I sent you then that could take some MPH away. If you need to try a different exhaust housing, just give me a call and I'll let you try something else if it looks like thats an issue. I have done that for others when the situation warrents it.
hope that helps,

 

[Reginald West]

Jack
Your right I did switch the exhaust housing but I put another .81 on the turbo because it had the provision for the delta gate on it, and at that time I was trying to run 2 delta gates.I just used a block off plate when I switched to the race gate.

I have checked the headers all cracks have been repaired and Ken Duttweiler just rebuilt the heads about 6 months back.The rpm seems to be good it shifts out of 1 and 2 at about 5500 and it goes through the lights at 6000.

I may give you call on monday about the housing .



REG

 

[Reggie West]

OK here are my observations from the Jr tuner.

DFI program was trimmed 10% last night and the EGTs went to 1650 and no more. So that was good. Dad said there was a noticable improvement in spool up ( if you can believe that with a ball bearing turbo) with the higher EGTs.

On the footbrake he could build 10 psi easily and leave the line well. His ET's were 10.79, 10.89, 11.00 and 10.85. The difference in ETs I would contribute to his 60 foot times. If he was running a 1.6X 60 foot he was hitting the 10.70 or 10.80 timeslips.

Timing. On the DFI map that is used by the ECM, this would be when you are in the Edit ECU side, I increased the timing to 19 degrees max. I placed these values in the cells corresponding to 25 psi on the map. Remember the MAP sensor reads in BAR so I figured 1.7 BAR is roughly equivalent to 25 psi. Bottom line, no change in MPH. The best speed out of the car was 127.9, the other runs all stayed within 1 mph of that speed.


Here is what is confunsing me. With a 1.6 60 foot, that is a decent launch with a foot brake. There is some improvement to be had with better launches but it cant equate to the numbers we are looking for.

1/8 mile speed is 102 to 104 which to me is pretty good. His 1/8 ETs are 6.9 to 7.0.

At the 1/4 mile mark the speed is 126 and that is all. Dad is right we are hitting a wall here. Should there not be a higher increase in mph at the quarter than what we are getting. The difference between the 1/8 mph and the 1/4 is 22mph.

It should be more but this is my uneducated guess.


This is what we saw last night maybe something stands out to you guys. As a matter of fact that difference in mph has stayed pretty much the same with the three turbos we have had on the car.

Am I missing the obvious here? Jack, Bill, Rob anybody?

 

[lazaris]

Reggie,

What about the converter? Your crossing the finish line at 6000? I assume your using a 28" tall tire with 3.50 gears if I remember correct? Thats around 10% slip. I beleive Ted A went from 128 to 134 mph with just getting his slip reduced from around 11% to around 6% on a converter change. Just something else to consider. However with that size turbo at 25psi you should have more mph reguardless. Its a 4 bolt correct? Maybe you do need a .96 but I think others have gone faster with a 4 bolt .81. What springs and or pressure are you running? Hyd Roller? Specs?

 

[Reginald West]

Lazris

Its a 4 bolt and the cam is a 224 solid lifter, I not sure about the springs but I could ask Ken Duttwieler. We have changed the converter about 6 times all the way from 3300 stall to 4500. The 3800 that is there now seems to be the best.


REG

 

[Bill Lankford]

Hi Reggie,

Don`t know if this is your problem or not but this is what happened to us.
The first of this year when we changed Bill Raglands car from stock computer to old style DFI we put in 18 degrees total timing.
The car was a dog on mph, sounded lazy on top. We lost 5 mph in the 1/8 and egt`s where up. Slowly bumped timing up and with each change mph went up and egt down. Ended up at 26 degrees with mph back to 119 and egt`s at high 1500`s.
Everone I talked to said map timing was 4 to 6 degrees less than real timing but ever check with a light showed at any rpm map and actual to be the same.
Two weeks ago car ran 5.80`s @ 119 in the 1/8 with egt`s at 1580`s .


Bill

 

[Reggie West]

Sounds just like what we are dealing with right now.

Timing, timing, timing.

If I read that thread right Lazaris, the more timing you put in the map, the higher the EGTs went as well?

Thanks for the help.

 

[EightSecV6]

Pull ALL of the rockers and leak the engine down. Solid 224 aint gonna cut it at 5500, we use cams of that duration with hydraulic lifters and shift at 6000. How many passes on the springs? Will it NOT rev past 5500?I would "waste" the time on the exh hsg.maybe not first but if it is one of the things you've changed, and it is causing your problem, it will be well worth your troubles. Are you sure it is machined properly for your wheel?It may not give you 10 MPH back but if you have a back pressure issue, especially since turning the boost up makes NO difference, I wouldnt say that discounting it is the "bottom line" If you "help" back pressure you will "help" performance.
While I dont recommend running 25# of boost to get the job done, I can tell you the EGTs are too high, you are not running enough timing. What balancer is it? Have you defaulted the map and shot the crank with a light? Maybe the interruptor ring has slipped?
As Jack said something is going on and I'm sure if you were closer we could find it.
Bill Anderson

 

[EightSecV6]

Damn must have been typing at teh same time.....I'm SLOOOOW