Detonation Problems

[xounlistedxox]

I'm now running the motor I was building when I started this thread. Rebuilt stock forged piston bottom end from a 91 5.0, trick flow tw 170 heads, holley systemax 2 intake, 70mm throttle body, upr boostmaster pipe, bbk shorty headers, bbk catted x pipe, flowmaster delta 40's, f cam, 3.27 gears 2975lbs

I now have an msd 6 btm, and an aeromotive 1:1 rising rate fuel pressure regulator. zI set my fuel pressure up exactly how aeromotive recommends 48psi without the vacuum line hooked up. Running MSD wires, and ngk plugs gapped @ .035 Have only on rare occassion heard detonation, but it's very infrequent. Still no tune.

With a nearly new engine complete with sensors and all it's running a lot better than it used to.

My SN 2000 has the upgraded impeller. 6" crank pulley 4" head unit pulley. I've seen about 7.5psi on my boost gauge

-Now I just need to find out how much timing I should be running for CA 91 octane on the street, and how much total timing on sunoco 100 octane at the track. My computer is an a9p, so it has more aggressive timing curves than an a9l.

ECU	1000 rpm	1800 rpm	2600 rpm	3500 rpm	5000+ rpm
A9L	8 °	18.5 °	22.5 °	22 °	26 °
A9P	21.25 °	21.25 °	27.25 °	26 °	30.75 °

-Updated Info:

Got my wideband installed today 3-28-13. I picked up a new lc-1 setup and installed it. I did some adjusting today to spark and fuel. I wound up running out of time while tuning(had to get ready for work), but as soon as my rpms hit 5k+ it goes lean into the low 13.x range. This is after turning the msd btm up to remove about 2.75* timing per lb of boost. My base timing is 8* btdc. As you can see by the graph above my A9P computer adds in a ton of timing, 30.75* advance @ 5k+ rpm. I also turned the base fuel pressure up to 55psi & am using an aeromotive 1:1 rising rate fuel pressure regulator & still runing out of fuel. I'm thinking I need to get an A9L computer to be able to properly adjust my setup since I would rather not run base timing of less than 8* btdc.

Update
3-31-13 Installed an A9L computer yesterday. Turned BTM down to 1.5* timing retard per lb of boost. With the A9L installed my wideband instantly stayed in the 12.x:1 air/fuel ratio. Now I just need to get out there and dial it in more. It feels so much better than when I had the a9p & pulling 3* per lb of boost.

[Michael]

I'm not very familiar with supercharging Ford vehicles so you'll have to forgive my naivety, but the first question that comes to mind is whether the car has been tuned or not. If you're still running the stock ECM (and stock chip) that might be where your problem lies.

Are you running an FMU?

Another suggestion would be to consider swapping the MSD 6AL box for an MSD 6BTM box. The 6BTM adjusts the timing based on the amount of boost; the 6AL box only provides an adjustable soft-touch rev limit.

[Duke]

How much fuel pressure are you running?

[zray]

you already a mostly msd ignition. what not get one of these ? if your problems are timing related this product would be the easiest fix:

http://www.summitracing.com/parts/MSD-8762/


Z.

[xounlistedxox]

I'm not very familiar with supercharging Ford vehicles so you'll have to forgive my naivety, but the first question that comes to mind is whether the car has been tuned or not. If you're still running the stock ECM (and stock chip) that might be where your problem lies.

Are you running an FMU?

Another suggestion would be to consider swapping the MSD 6AL box for an MSD 6BTM box. The 6BTM adjusts the timing based on the amount of boost; the 6AL box only provides an adjustable soft-touch rev limit.

The car has not been tuned. I'm building an engine currently for this car which will be a rebuilt 302, trick flow twisted wedge heads, custom cam, holley systemax etc Originally I was going to save the supercharger for when I finished the other engine, but I couldnt help myself and installed it onto the current engine.

There is no FMU on this vehicle since I'm running 42lb injectors I didn't think it would need one since the injectors are huge for a basically stock engine even with a supercharger.

I have been considering getting the BTM box instead of the 6AL, but at the moment I'm still putting funds towards building my engine.

[xounlistedxox]

How much fuel pressure are you running?

I don't have a fuel pressure gauge, so I don't know currently

[shopo27]

I just puchased a boost timing master 5462 universal model. Not running a MSD ignition.. Waiting for it to install. I hope it works out like iI have heard. Currently base timing at 6deg. with unit installed should be able to go back to 10 or 12 base timing and set 11/2 boostretard starting at 1lb. and let err rip

[Duke]

I have no boost retard, my timing is at 12 degrees 2 degrees advanced. You said you have a stock fuel pressure regulator i'm running an adjustable one at idle. I have 40lbs of fuel pressure when I nail the throttle. i've got it set to 60lbs. i have no detonation problems. This is what I have: 302 stock block, f303 cam, edelbrock performer heads, gt 40 upper and lower intake, paxton sn2000 pullyed to 3.5 '' 8lbs of boost on the blower, 36lb injectors and an afm powerpipe, pro m 75mm maf, 70 mm throttle body. When I pull the plugs after a hard run it's a little fat a darker brown with no signs of detonation.

[shopo27]

Wow no need to pull timing for boost. Damm must have a real good tune

[Duke]

good fuel and enough fuel you cant starve any engine! and you have to be able to see detonation on the plug, it looks like sand on the electrode. supercharged engines need fed!

[xounlistedxox]

good fuel and enough fuel you cant starve any engine! and you have to be able to see detonation on the plug, it looks like sand on the electrode. supercharged engines need fed!

This is why I was thinking about mixing in a gallon of e85 with my 91 octane. We only have 91 on pump here in CA

[zray]

"........... my timing is at 12 degrees 2 degrees advanced. ........"

can you explain a little what this means ?

For example, If I was to describe my timing I would say it is 15 degrees BTDC static timing (at idle), with 18 degrees mechanical advance for a total timing of 33 degrees. this is slightly different from stock 289 K code Hi-Po engine timing of 12 degrees static plus 28 degrees mechanical for a total of 40 degrees BTDC.

Z.

[Duke]

get an adjustable fuel pressure regulator, Summit racing has them im running a mallory adjustable fuel pressure regulator i think its adjustable from 35 lbs to 70, stay away from the e85 you'll have to put bigger injectors in! Im just running 93 kwik fill gas. 12 degrees at idle 1000 rpm

[Duke]

are you running the f.m.u that you should have with the supercharger? if not that's where your detonation is coming from under boost its reversing the fuel back to the tank instead of putting it to the fuel lines and injectors. plus you need more pressure than stock with bigger injectors.

[speedytang]

Your problem is sea level and only 91 CA. Octane which is like 89 octane on the east coast. The best fix and cheapest would be a Meth/Water injection to get your octane to a real usable level. Pulling back timing will cause additional heat in the heads and cause pinging(detonation) also. You should be able to run 24 total advance on 7 psi with 91 octane in the real world but not in the CA. world.