Dyno Tuned yesterday...... something isnt right..... 404hp 396tq??

95CobraMike

95CobraMike

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Apr 12, 2004
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#1
Well, i finally got tuned at alterative auto performance in mt clemens michigan by Lidio.... Something isnt right...
i made 404.4 rwhp and 396 tq at 10.9 psi + methanol injection :shrug: not to mention ported TW heads, wolverine 1190 cam, a cam almost exactly like the TFS stage 1, and a ported upper and lower cobra intake.... (plus the rest of the stuff in my sig)

here is the sheet:

PICT0184.webp


In the a/f ratio you can see at about 3300 rpms where the methanol inj kicks in and the a/f starts going down to 12.5

Why is my car peaking at 404 hp and 396 tq??

now it also has a hanging idle issue when decelerating and what feels like a miss while cruising under no load (that goes away as soon as i accelerate even the slightest bit)

needless to say i was dissappointed.... Lidio said that cars comparable to mine should easily make 425-450 easily :shrug:
 

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#2
Timing was set at 12* and the BTM is at .5
Fuel pressure is the one thing that bothers me.... with the vac tube off, my pressure gauge read 56#'s shouldnt that be around 40??

if i turn that down to 40 now, after the tune will it make me go way lean?
 
#3
Alternative Auto is a good place to go, Lidio has helped me out of a few binds.
If you lower the fuel pressure you may go lean, Are you sure your gauge isnt messed up? Do you have one on the fuel rail or a electric one inside?? I would verify the pressure first, I would look more at the meth injection since it seems that once it comes on your A/F dips, You should be making more than 404. Did Lidio give you any Ideas or things to check??
 
#4
he mentioned long tube headers but i think there is more to it than that... he said i could add some more timing if i wanted to at the distributor, but other than that he didnt say anything other than i should be making more power....

i dont think the gauge is messed up, it is nearly brand new, its the kind that mounts on the fuel rail
 
#5
Does it start to ping or have detonation if you dont use the meth injection??
Long tube headers are not going to get you that much, I would guess 7 to 12 hp maybe. Do you have a wideband or one you could use, then you could play with the fuel pressure to see what it does. I would assume that lidio did that though when he was tuning. Maybe the cam I have never run the wolverine cam. Your A/F ratio shouldn't be so up and down though, A little variance is normal but something else is going on there...
 
#6
Mike

Here are my thoughts :)

You seem to be too lean. Most blown combos I've seen shoot for 12.0 to 1.00 give or take a bit.

IIRC, you should see a rise of 1lb in fuel pressure for each lb of boost. If that is so, would that put you at about what you saw?

What are the detalis of fuel pump/pumps? Perhaps you are starving for fuel :shrug:

Seems odd the topic of spark was not talked about much from what I've seen in this thread as lots of power can be found there.

My thoughts about spark for the pull would be as follows:
pcm has about 25 total
add 2 for your dizzy value = 27
del 5.5 for your btm & 11lbs of bost = 21.5

21.5 for a total value ... anyone have any other thoughts here?

If you moved to LT's you would gain ... but not all that much IMHO.

I'm kinda confused here :shrug:

You talk about fuel pressure & working with the dizzy.

After your baseline pull ......

Did you tune with mechanical means
or
Have Lidio burn you a chip

Grady
 
#7
I agree with Grady, and additionally, the AFR looks downright scary to me. If the methanol nozzle clogs, and they do, or the methanol pump fails, and they do, you'll go really lean and probably destroy the motor. As lean as it is once it is in boost, it may do that anyway even with the methanol injection. I also think that lean with 21* of total timing, if that's what is in it - is too much spark (if the methanol fails), the methanol injection is probably making that much spark OK as long as it's spraying. You could get away with that much spark without the methanol if the AFR was 11.5 once it's in boost. it also looks like you are running out of fuel or in need of an adjustment to the transfer function up top.

Stock the FP is 39.5 with the vacuum line off and plugged. If your base FP is 56, then at 10# of boost you should see 66 FP - which is pretty high. You have to leave the FP where it is after the tune or it WILL go leaner at WOT, because the injectors will act smaller than they are. Would have been OK had it been tuned with FP stock.

Usually, with a tune if the spark tables have been normalized, there is no reason to run a BTM.

Lean is mean, but if you straighten out the fuel curve, and renormalize the spark tables properly, you'll find some power. I'd also wager to say that you are running the biggest spray head that Snow makes - which IMHO is way too big. Spraying too much, no matter what timing you run, just kills power. We've tuned a lot of cars with methanol injection and some have lost power no matter what you do - we also have had an equal number gain a lot of power with it - it all depends on the combo. Normally, you just spray enough to lower charge temps significantly and then no more. When I had my KB blower on the 5.0 I used a TINY nozzle - it just sprayed a 'fog' type mist and it worked really well.

Good luck with it!

Don
 
#8
after the inital run (232 hp 5.5 lbs of boost he only ran it up to like 4000ish rpms) it was all chip tweeking done by lidio.... i didnt touch anything mechanical other than tightening the s/c belt

this was my first time to a dyno, i didnt know what to do or ask about or watch for... so i pretty much let him do it, i figured he knew what he was doing more than i would have...

as far as the meth kit, yeah i am somewhat worried about it failing but not too much, i dont get into the boost a whole lot but i do understand that if i do and its not working i can be in serious trouble...

what can i do about the AF ratio? what would cause it to be so abnormal like that?



thanks guys

Don, maybe i should bring it to you??? you are a heck of a lot closer i figured that going back to lido would be a good tune and id save some cash by already having a chip from him.... who knows
 
#9
Mike - Don't think the meth kit can't fail - they do all the time. When I had mine on my KB 5.0, I had nozzles clog 2-3 times with little debris in the lines. I also had the hobbs switch fail once. Luckily I was just using it to cool charge temps only, not as an octane 'helper' and I had my ACT set up to pull timing when things got too hot so it saved my motor.

We've seen 2-3 cars that supposedly had 255 pumps either installed by someone or on the car when purchased that ended up having stock FPs.

You will never catch me bashing another tuner, so I assume there is some reasoning behind the AFR. Lidio is a really smart guy with a good reputation. Dunno what's up with the AFR, but we wouldn't tune it that lean at all - that's not our philosophy. My own car I run at 12.2 AFR only because it is MY car and if I blow it up, it's my own stupid fault - but never on a customer's car.

Like I said, my best guesstimate of the power loss is the meth kit spraying too much. It's always a good idea with a meth kit to do a tune without it, then a switch chip with it. You can then see its impact on power.

If we can help, or you need any more info, just holler. [email protected]

Don
 
#10
i will start by looking into my fuel pumps and see what i really have there and go from there i guess

isnt there a way to turn down the pump's pressure on the snow kit? (i just found this out today) my question is how do you know what your pressure is after turning the allen screw? :shrug:
maybe i should just forget the snow kit? but then all the tuning we just did goes down the drain....
 
#12
95CobraMike said:
Dropped the tank, heres what i found....
Walbro GSL392 255lph high pressure external inline pump
Walbro GSS340m 255L/hr High Pressure intank Pump................

now what?
Click to expand...

I checked my notes Mike and I saw the same pn :nice:


GSS307 255 lph high volume pump

GSS340 255 lph high pressure pump

Grady
 
#13
now im starting to think too much methanol

do any of you know how to adjust the pressure coming out of the snow kit's pump so that you actually know what pressure you are at?? i think allen screw all the way in is full pressure, but if you loosen it what are you at now?
 
#16
so if my calculations are correct, i should be running between 60 and 65psi for my pump pressure.... (assuming a 625ml/min nozzle is in place)

so at 11lbs of boost i should be injecting 18% of my total fuel as being 50/50 water methanol mixture...
if my flywheel hp is about 500 that means @15% of total fuel i should inject 529ml/min so convert that into 500hp at 18% and you get 635 ml/min of 50/50 mix

nozzles are rated at 60psi pump pressure
so a 625 nozzle squirts 635ml/min at about 61 psi

So what happens to all this mombo-jumbo if i am running straight methanol???
what happens if im at like 150psi on my pump psi????

Lets go see what my pump is set at!
 
#20
I am not saying he is right, but if you look at Alternative Auto's Water Box Article I think it explains why Lidio tuned it that way:
http://www.alternativeauto.com/waterbox/waterbox_main.html

"So if your booted combo is safe and runs good with a A/F of 11.5, with the Methanol flowing we would run a little leaner in the same application, like 11.8 to 12.00:1 - also adding more timing while the methanol is flowing.
Methanol is also a huge octane booster. We’re not sure exactly how much it raises a typical 93 octane application, but some say as high as 115-120 octane. Not sure about this yet, but it definitely raises the octane substantially from 93 judging from the amount of additional spark we can add to a non-methanol tune. Methanol also lowers the inlet temps quite a bit - as much as 60 - 100+ degrees."
 
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