Dyno Results

[Chuck Leeper]

Not exactly what I was looking for...
Best pull, [No 13] was 604RWHP and 638 TQ. Was looking for 700 TQ. [25psi boost]
Engine pulled great to 4500, started stuttering a bit, went fat,[O2 corr at 4000 was 4% taken out.. hit 4500, started the stutter and the O2 was then pulling 11%] and then managed to run on up to 6200 B4 the pull was concluded.


I had an interesting experiment w/ the dual 9" cleaners I have installed.
Pull 7 was at 20psi and the cleaners were in place. Resulting in 576HP/604 TQ.
Pull 8 was w/ the intake pipe off at the turbo inlet. Resulting in 556Hp and 617TQ !!! We noted an immediate rise in MAT. Begin pull 80* end pull 122*!!
Rest of pulls were w/ the pipe in place but not hooked to the plenum box.
Pulls 5 & 6 were with exh closed,[5] and dump open,[6] Found only 3HP and 4#TQ improvement w/ it open...

Will have more to share when we look at the external data logger.
I had FP, boost, rpm and exh backpressure instrumented.

Anyone have any input on the stutter, going fat scenario??
I'm leaning towards the spark not getting there, the fuel not being burned and the Wb sensor seeing rich. Sound logical??

Also, Anyone have any ideas as to the best way to get the spark intensity up to par?? I have new coils and module to install next.
MSD?? Etc??
Thanks for the help!
Next time it's track testing..

[Reggie West]

It sounds like you were blowing the spark out of the cylinders at 4500 and beyond. I have seen that before.

You can re gap the plugs to .025 and that will solve it.

Getting the fuel map correct will help too.

We made the same numbers on a dyno with a 72 turbo, our problem was the tires started to bounce on the roller! That was interesting to see.

[quickt]

Originally posted by Chuck Leeper

Also, Anyone have any ideas as to the best way to get the spark intensity up to par?? I have new coils and module to install next.
MSD?? Etc??
Thanks for the help!
Next time it's track testing..

I like my MSD I think it helped. I had problems with a miss at 4800 that had a mind of its own. The MSD installed and never have seen the problem again. Tighten the gap on the plugs should also help.

[Chuck Leeper]

Currently the plugs are at .032 tight. AC 42LTS.
Will test the coils and module and tighten up to .028-30.
Further thot leads me to believe that this is the problem.
IE: Since max BMEP occurs at max torque, I looked again at the pulls and found that max torque is occurring in the 4200 to 4400 rpm range. Thus the max cylinder PSI is occurring then, and "puttin the fire out"!!
[The 4500 rpm comment should be refined to say 42-4400, as I was watching the dyno tach and listening to the engine tone.. a lag in there no doubt]
The exh gas data logs should prove to be interesting as well. Could be the poor lil ol "P" trim .82 hsg may just have a bit too much backpressure...

Also, the engine has a mild hyd roller, with timing at 218/212 @ .050 Not a cam that will provide dramatic performance above 6000.. Oh well, it's streetable, and MOST "Moosetwangs" don't know what they got hold of!!!


Thanks for the input!!

[REDS HOT AIR]

why no sig with combo ??

[Chuck Leeper]

Red, it's all SSS!!!

[86brick]

Chuck, what kind of heads are you using (ported aluminum GN1's, ported aluminum M&A's, or Stage II heads)? Also, I'm guessing if it's a P-trim 72 turbo it's also a 3-bolt? Sounds like a mild Stage II combo, but it still probably has more left in it once you get a few things sorted out.... At your age you don't want all that much HP anyhow J/K

[REDS HOT AIR]

Originally posted by Chuck Leeper
Red, it's all SSS!!!

tight azz

I gotta leave the lil league and step into the big stuff one day but not looking to go all race so im checkin streetable combo's


sounds like it'll run good once tuned in and you get the missfire out.

[Chuck Leeper]

I AM NOT that old!!!
Actually the combo has GN1-R's ported. The turbo is a 4 bolt 72BB from Turbonetics.. 95# inj's, yadda yadda...
277Ci stage 2.. BGC intake, PTE ft mt, and a t-400.
Hopefully I'll get it right B4 I go on Medicare!!

[86brick]

Maybe you should try the Q-trim housing cause I would think a bigger cube motor like your 277ci Stage II could benefit from it especially when the boost is turned up to about 25-30psi when on kill.... Just make sure you have some Depends on when you get it running right and turn the wick up

[BoostKillsStres]

Chuck,
What was your best MPH before these sessions and at what boost level? Have you made any changes since then?

Have you run a tester on your coils just to see? Maybe at your level the MSD isn't a bad idea. Does FAST do a coil on plug setup, just an idea.

Hope to see you at the meeting.

[JayC]

Unless you just have to have the two step on the MSD, I'd look at the eDis. You could also try twisting Bob Bailey's arm to finish the ignition adapter he has "finished in his head."

[Chuck Leeper]

Brick, the folks I worked with gave me a yrs supply of Depends when I retired. Still have some !!! The Q trim is next... I agree that it could help.
The traces of exh backpressure don't appear to be reliable.. something wrong w/ the calibration, I'm afraid. Some look to be in the 2 to 1 range, then some over 100psi!!
Anyone know what we should be shooting for as a ratio to boost?? I was under the impression that 2 to 1 is ok???

Mark, the car runs consistently 10.20's/132+, regardless of the tuneup or combo.[old combo was unported heads and a t-70]
The engine would pull to 6000, but was slow getting there. After the combo was changed, the same et and mph was seen. Only common thread was the air cleaner..9" KN.[The folks at KN engineering were quick to find this and supplied a sheet of calcs to figure the necessary cleaner size. That is posted on GNTTYPE.website]
W/ the new power w/ the T-72 and the ported heads, more inj, more fuel system, car performed exactly the same, only would not rev above 5700..added dual 9" KN cleaners and whamo! 6200!
However, this test session was the first time the boost had been raised to 25.. never above 20 -22 B4.
I have a tester and am checking the system today!

Jay, I'll send Bob an e-mail and see what's going forward, if anything.
I agree, the E-dis would be a neat solution. will look into it.

Thanks, all for the input!!..

[Reggie West]

FAST does make an EDIST box to go along with their ECM.

It is a plug and play deal but you have to go buy the coils.

Price was $400.

We are looking at doing that soon too.

[Ted A.]

Chuck, you better get that thing running right. Old Maverick is going to hand your a$$ to you with his new combo.

[Chuck Leeper]

Ted, he best to get busy and send Steve Y. his MAF sensor back, or outrunning my ol bucket of bolts will be the least of his worries!!!
Giving up his "Mr nice guy" position won't matter!! That POS he's supposedly throwing together will never see the light of day!!
He could do it the easy way and spend some of his "six figure income" and just buy me out!!

Got some serious info here! enuf of the nonsense..
The folks at the dyno called. Seems the problem we were seeing w/ the recording of some of the pulls, was due to a high drop off in acceleration rate of the drums to make the software believe we had changed gears!!! [we had to go into the dyno computer and change some calcs to be able to read the charts]
The drop in pull power was exactly at the same rpm that the engine ign system began to break down.[max torque]
Once the ign is brought up to snuff, the car may actually run!!

Again, anyone w/ any more ideas, plse respond..
TIA,

[lazaris]

Chuck,

You may be onto something with the ignition but I would think that if the spark was getting "blown out" it would have shown up with some popping or misfires. I had some 3rd gear popping a few years back when running .035 gap, closed it down to .032 and no more misfires. Im installing a MSD Dis 4 this year more so for the 2 step but this may help in other areas too. I would look really hard at those BP #'s it really becomes an issue at higher rpms. Seems you ruled out an intake issue at this time but you wont know for sure untill your sure the BP isnt hurting it. See you in MIRC.

[Chuck Leeper]

LAZ, Actually, I could hear the engine missing. I was not in the seat during the pulls, but at the dyno console.
I may try a EDIST system.. we have one for the other project we are working on. I think we also have enuf coils to get it together..
First, I will test the coil and module and titen up the plugs...

Thanks!

[TurboTR]

Hmm. Well FWIW mine still has the stock ignition, plugs gapped at .030'ish, boost over 30 psi, and with nitrous jet > 100 hp size and it has no misfire problem like you describe. Not saying there isn't room for improvement, just that it can work IME, FWIW. It probably dynos in the 800 rwhp range like that.

What made a big diff on mine was going to a much better pushrod, custom ones from Manton Racing, along with a bigger solid roller stick. IMO your cam is awfully small for the combo. I've found that a 242/242 is still great for a street/strip combo, still very streetable since it's a roller (ie it still has pretty low seat timing). In fact I think we'll go a bit larger even in the near future. I couldn't tell any negative difference really in mine as far as streetability and spoolup go, going from a 224/224/110 @ 105 icl to a 242/242/114 @ 110 icl. It did register lower idle vac of course, but still about 12 in hg range. Big difference in wot perf though. In fact it picked up some 4 mph in the 1/8 on the 1st pass with the new stick and pushrods with no other changes :-) Assuming you need it to run hard out past 6000 rpm during an actual track run of course. Mine runs from about 6000 up to ~ 7000 rpm max during a track pass. Averages about 6500 during the run I'd say.

>I'm leaning towards the spark not getting there, the fuel not being burned and the Wb sensor seeing rich. Sound logical

IMO no, since the sensor doesn't detect fuel. It detects oxygen. It should read lean in that case. JMO.

I'd say that 2:1 exh/int pressure is not out of reason here. Back with the 235" S1 mill I measured about 40-50 psi in the exh with 25 psi in the intake. q trim 4 bolt '76, same ~ 3-4 yr old one that's still on the new mill. If nothing else I'm sold on the single BB durability :-)

TurboTR

[Reginald West]

Ok guys when we had mine on the dyno plugs gapped at 32 car put 550 horsepower to the rear wheels.Gapped the plugs to 25 same boost car went to 625rwhp.I have not dyno it since we added dis4 box.