1979 SA RX-7 LS Turbo Build (8.93 @ 153)

[cyipher]

I recently changed to E-85 and i can tell you that when my car went into the mid 10's afr (gas range) I would have a issue with the car ramdom breaking up. I was an issue with my wideband formula once i fixed this and got my afr to 11.8-12.0 the issue went away. Also dont rely on specking of the plugs with E-85, due to the lower carbon build up from e-85 you may not have any carbon to knock off the piston and on to the plugs.

Where is your 02 sensor located? I was getting false rich readings when I had mine in the manifold. Moved it to the muffler tip and it read quite a bit leaner. I know Scottie and a few others run on the rich side with no issues. I had planned on leaning it out a bit on the dyno.

Do you use your knock sensors? Mine were going bat shit at 1-2psi and pulling a ton of timing. I ended up shutting them off. I was seeing 3.1v (5v is max) or so on the 8psi pull. I assumed this was just due to the solid motor mounts and or noisy glide sending odd ball harmonics through the block.

 I was thinking I’d wedging my WG open to get little to no boost.  Then datalog what’s considered a “normal” amount of noise (voltage) on my knock sensors. Then setting the sensors up to pull timing if that normal point is exceeded. But if I'm already getting 3+v the engine may just be to noisy to pick up knock properly.

I was ASSuming I wasn’t detonating at 8psi, but I don’t know how I’d tell if I can’t use the plugs. Pretty sure speckling (at least major detonation) is the result of alum specks from the CC. Defiantly saw speckling on my E85 buick and 4g63. Can see a tiny bit of pitting on the pistons usually as well.

My W/B is in the downpipe. Normaly you'll knock some carbon off the piston and get some on the plug from mild detonation, what you have pictured is a a engine 2 seconds from melt down or atleast a cracked piston or 2. I do have my knock sensors on but i did de-sensitise them a bit back when the car was N/A and i know it wasnt false knock. I now see one little spike of knock on the 2-3 shift every pass so i know its most likey false and i need to adjust them a little more, this was on e85 non intercooled and on 5psi

[forcefed86]

My W/B is in the downpipe. Normaly you'll knock some carbon off the piston and get some on the plug from mild detonation, what you have pictured is a a engine 2 seconds from melt down or atleast a cracked piston or 2. I do have my knock sensors on but i did de-sensitise them a bit back when the car was N/A and i know it wasnt false knock. I now see one little spike of knock on the 2-3 shift every pass so i know its most likey false and i need to adjust them a little more, this was on e85 non intercooled and on 5psi

I wouldn’t go that far... Unfortunately I've pulled the plugs and found that several times in the talon over the years. Almost 20k on it now and it sees a ton of boost daily.  But I hear you. It’s never something I want to see.

 What kind of voltages are you seeing from your knock sensors? Or can you not log that? Do you have solid motor mounts?


Thanks!   

[Badbird_96]

Hey i just realized this was your car lol. Ive been reading through your thread to see what i need to do to mine lmao. Im definetely not going boost though haha

[cyipher]

My W/B is in the downpipe. Normaly you'll knock some carbon off the piston and get some on the plug from mild detonation, what you have pictured is a a engine 2 seconds from melt down or atleast a cracked piston or 2. I do have my knock sensors on but i did de-sensitise them a bit back when the car was N/A and i know it wasnt false knock. I now see one little spike of knock on the 2-3 shift every pass so i know its most likey false and i need to adjust them a little more, this was on e85 non intercooled and on 5psi

I wouldn’t go that far... Unfortunately I've pulled the plugs and found that several times in the talon over the years. Almost 20k on it now and it sees a ton of boost daily.  But I hear you. It’s never something I want to see.

 What kind of voltages are you seeing from your knock sensors? Or can you not log that? Do you have solid motor mounts?


Thanks!

No, never logged that. I have hockey puck motor mounts that have a bolt straight thru them. while it is mostly solid, im sure it helps with harmonics.

[turbotalon1g]

You on DSMLink?

[Burntz]

Dsm Link? On a turbo 5.3? Im assuming he's using HP Tuners...

[forcefed86]

Using Gen1  aem ems.

[turbotalon1g]

I should of been more clear (as usual), i meant on the DSMLink forums.

[Burntz]

Its actually called ECMLink 

[forcefed86]

Finally back from a weeks vacation and got a chance to look at the car a bit. It fell on its face the second run because it popped off a coupler. Not sure if it was the t-brake launch I tried the second time out or what. The turbo and piping all have beads, used the good "T" bolt clamps as well. I may just be tweaking the front of the car too much. Didn't think I'd have an issue with couplers at 12psi. I think I'll have to remove the bumper to re-clamp it, hope this isn't an ongoing battle.   

*update* reattached the clamp and it held solid to 17psi.  Rolled into it around 45mph in high gear. Once I hit full boost I was smoking the tires at around 70.    

[Burntz]

Now thats whatsup!

[forcefed86]

Finally got everything in order for another track visit... I hope. 

Blew off the throttle body coupler early today. Found the BOV wasn't working, spring was too strong I guess.  Dropped in the next lightest spring and it was open at idle.  So I got out the old MAP gas torch and put the original BOV spring in the vice and cranked it down a half inch or so. The hit it with the torch. Lucked out and it seems to work now. I can actually hear it vent and haven't had anymore coupling failures since.

Got a good 10 tuning passes on the street today.  I've got it all dialed in at 12 psi & 18* of timing. Feels healthy! I'm guessing 130+ and low 10's with a lazy foot brake launch.   

[N2v8fcs]

watching and waiting ...

[SOB Racing]

Instead of torching the spring....I've just added large washers inside the BOV to shim it and add some preload to adjust the opening point.

[forcefed86]

The lite spring I tried was just way too lite. I could open the valve myself by sucking on the nipple.   

I may have to shim this one when I turn the boost up. 

I built this little setup... Should allow you to dial down your vac at idle and still allow full pressure in boost. It did work but I had to restrict the vacuum to basically nothing to get it to close with the lite spring in it.