Since not everyone is following my build thread, I decided top ost this here.

Well went to the dyno and on 21.9 lbs it made 661rwhp at 4900 and 719 rwtq at the same RPM(4900) on the Mustang dyno. If you use 12% to convert the Mustang to the dynojet its about 740rwhp/805 rwtq, but those are only guesstimates. The first ones are the only hard numbers I have. Its like it's hitting a brick wall at 4900. On the last pull(in the following video) you can hear it sounds like a rev-limiter. I know TPI is no high RPM motor, but it should pull more than that. Looking into it now.

Any help on the issue after 4900 rpm is appreciated!

http://www.youtube.com/watch?v=EPcxA...layer_embedded




messing with the Megasquirt




Dyno graph following soon along with my msq and tunerstudfios file to hopefully figure out the 5000rpm issue...

 

i'm curious how that motors staying together with 21 lbs of boost an 14.3 air fuel ?

 

Wideband was disconnected and the wb from the dyno was put in the collecter at that location. It was reacting faster than the AEM I had installed. Forgot to add that, sorry

 

what cam and valve springs? What ignition system and whats your plug gap?

 

what fuel system as well

 

http://www.compcams.com/Company/CC/c...ookieSupport=1

Valvesprings were chosen by a local high HP builder with this setup and boost in mind, but I have thought about them as well.

Gap was .025. Brought it down to .015 and no change in HP or the way the car was running.

MSD dizzy is being used as a VR signal to the MS. MS sends it to the digital 6, which then feeds a blaster coil.

I am getting a new pickup(that goes inside the dizzy) and coil as well. I figure that neither one can hurt, ya know.

A1000 pump, inline filter and regulator that is NOT boost referenced. FP starts at 45 and by 5k is still at 42psi(car goes rich or lean at that point(VERY wierd). That's why I'm thinking ignition issues that are causing the AFR to be screwy. Just got the laptop connected, so I'll upload the crappy dyno graph pics.

 

Just as a side note, while I was researching "large long tube runners" I came across some threads regarding the Porche 928 motor which has an induction system similiar to the TPI. They were wondering why there was a horsepower limit no matter what they seemed to do. Anyways it turned out to be the diameter of the runners.

If the velocity of the air in the runners is around "sonic" in speed it may in fact be choking off the air like a rev limiter. It could be approaching or going through the sound barrier.

 

That could VERY well, be the case. Just TOO much air in that little runner. The thing that is funny is that a turbotpi car on here experiences the EXACT same problem at 5000 rpm. You can hear it in his video as well. The horsepower limit I'm OK with. Just want more rpm than a diesel. My tq/hp numbers don't even cross, lol

 

Here are the run , msq for MS, and a HORRIBLE picture of the dyno graph, just so you can see how sharp it's falling...



right click save as(run)

http://jonsmithphoto.com/nuffnuffz28/1987Iroc/dyno.msl


Right click save as(current tune)

http://jonsmithphoto.com/nuffnuffz28...6-30-11(7).msq

 

Well if the cam has valve springs designed to support boosted applications and the aggressiveness of the lobe, then it likely isnt valve float

Ignition seems good, thats a tight gap, I only run about .028-.030" on my motor. So sounds like its not blowing out spark, but see what the new pickup and coil does.

Pump should be capable of more power but i've heard 800whp is about it and your close to that on a dyno jet...but you'd see air fuel drop off as rpm increased and power decreased, not necessarily hitting a limiter like you are.

One thing to note is lack of boost referenced regulator. I'd recommend one. Think about this.... 45 psi in the regulator so the injectors are spraying 45psi of pressure against intake runner pressure which on a n/a motor is 0 psig. With 21 lbs of boost pushing back at it, the effective spray pattern is now 45-21 = 24 psig of fuel pressure. That may not be enough to effectively atomize fuel or atleast could hurt the mixture combustion process enough to hurt power and rpm.

Check your VE tables at the point where boost is coming on very quickly. Does your VE tables increase at a LARGE rate as boost increases. Say at 5psi you have VE value of 55 and at 10psi you start to see VE of something like 70. Basically a large jump in VE indicating lack of fuel pressure is causing fuel supply to drop off so you need to compensate for much larger increases in VE and thus larger injector pulses?

So with ignition upgrades, i'd try a boost referenced regulator and see what happens. If that dont fix the problem, go with a FIRST TPI injection unit and see if that runner diameter increase will help. It may be choking the port.

 

I was thinking about that as well, although the dyno shows rich.... It may be trying to keep up and when it does it overcompensates in the VE tables?

 

59.0 59.0 133.0 198.0 198.0 211.0 211.0 211.0 218.0 218.0 218.0 215.0 220.0 228.0 233.0 233.0
61.0 77.0 135.0 200.0 200.0 198.0 198.0 198.0 205.0 202.0 199.0 196.0 199.0 212.0 216.0 222.0
59.0 77.0 133.0 191.0 191.0 178.0 178.0 179.0 178.0 179.0 183.0 195.0 193.0 195.0 200.0 202.0
57.0 75.0 123.0 185.0 177.0 173.0 174.0 173.0 171.0 171.0 177.0 189.0 191.0 193.0 194.0 196.0
65.0 78.0 158.0 157.0 173.0 171.0 164.0 169.0 171.0 168.0 182.0 190.0 191.0 192.0 196.0 196.0
66.0 76.0 151.0 149.0 170.0 157.0 168.0 166.0 159.0 156.0 161.0 188.0 191.0 191.0 195.0 196.0
90.0 82.0 133.0 130.0 132.0 129.0 130.0 151.0 148.0 138.0 153.0 157.0 184.0 181.0 175.0 175.0
66.0 65.0 139.0 137.0 140.0 142.0 150.0 149.0 146.0 131.0 157.0 137.0 143.0 137.0 113.0 113.0
39.0 50.0 104.0 110.0 118.0 111.0 116.0 136.0 150.0 145.0 162.0 172.0 152.0 156.0 157.0 157.0
44.0 52.0 100.0 105.0 106.0 107.0 111.0 134.0 148.0 133.0 151.0 173.0 149.0 155.0 144.0 155.0
41.0 42.0 85.0 91.0 88.0 88.0 119.0 135.0 149.0 142.0 149.0 174.0 144.0 149.0 155.0 152.0
40.0 46.0 78.0 89.0 83.0 91.0 118.0 127.0 145.0 164.0 139.0 103.0 77.0 81.0 82.0 82.0
32.0 42.0 46.0 54.0 60.0 72.0 69.0 67.0 68.0 65.0 53.0 61.0 73.0 80.0 82.0 81.0
41.0 39.0 37.0 48.0 56.0 51.0 54.0 51.0 44.0 24.0 38.0 63.0 74.0 76.0 87.0 90.0
36.0 37.0 34.0 46.0 47.0 46.0 37.0 50.0 38.0 40.0 47.0 71.0 71.0 87.0 84.0 87.0
45.0 45.0 55.0 51.0 55.0 50.0 27.0 28.0 35.0 50.0 50.0 50.0 50.0 50.0 50.0 50.0



This is a copy/paste from the VE tables..... left to right is 500-5700rpm and down to up is vacuum to 25 lbs...(0 is about 1/2 way up...

 

hard to tell without graphing but it does look like theres some jumps in there, not as smooth a transition. I'd still try the boost referenced reg and new igntion stuff to see what happens

 

I plan on it, thanks! Besides duty cycle is 93% up there and 103% when it goes ape **** at 4900, so more fuel pressure would surely help the injectors not have to work so hard! Just as an FYI, it will not free rev over 4900 either(or at least started to break up so I let off(and went full rich)) New coil is on the way!


Now for the bad news. Supercharger was vibrating some, did some research and found out the bolt was loose on the balancer, key broke, and it had just started to spin on the crank


Pulled and cleaned everything and reinstalled with a new key. When the balancer is 100% on, it has some play. I don't want to run it like that, so I talked to TCI today and am going to send it in and see if they can replace or repair it.

Oh well... Such is life I guess!

 

(8) 80 lb injectors at 100% duty cycle should support about 1,070 flywheel hp with a BSFC of 0.6. This would suggest that your tune is very rich.

 

Yes, but with 42-43 psi, a rich tune, and a mustang dyno, it's not too far off. They were at 93% until something happens at 4900

 

New balancer fixed my problem , but it almost wasn't was when the crank bolt stripped(after just using the bolt to pull the balancer up.) Thankfully we got it out and the new balancer is nice and tight!



Now I just put it back together AGAIN!

 

WOW. That is crazy! I am just curious....Why not a miniram, or superram? Why the long runners?

 

VE table is not always smooth, i had to bump up a lot of fuel in a certain section under boost.

 

You running your fuel pressure boost referenced. I tried to get away with not doing it, but it looks like my injectors are running out up top!

 

Honestly, I just like the TPI and when you pop the hood on a thirdgen that's what I think you should see

 

subscribed!!! that supercharger setup looks great!