power from a NA 7m

[BLACKCAT]

Stock C/R should be 9.2:1.

Here is my latest dyno.
128rwkw + 15% for our lower Aussie figure is around 197rwhp.
Should gain some more when I have a high flow cat installed to replace my 18 year old Toyota one.
I like my torque curve from 4500 to 6500 & how it pulls strongly in that rev range.

Mods:
BC264 cams, Comp Cam valve springs, 2 1/4 to 3" exhaust, Hurricane headers, home ported head.

 

[AJ'S 88NA]

I would think that an effectively designed header would actually help with lower octane fuels as it *should* allow for more scavenging of exhaust gases thus leaving the combustion chamber cooler for the next cycle.



I can't remember for the life of me... what is the 7M-GE's stock CR?

That's what I thought about headers, just was asking for anyother explaination.
I keep thinking it's around 9. something to 1.

 

[AJ'S 88NA]

Stock C/R should be 9.2:1.

Here is my latest dyno.
128rwkw + 15% for our lower Aussie figure is around 197rwhp.
Should gain some more when I have a high flow cat installed to replace my 18 year old Toyota one.
I like my torque curve from 4500 to 6500 & how it pulls strongly in that rev range.

Nice numbers, what mods do you have.

 

[Ma70.Ent]

Hm, well cuel said that he ran intake/exhaust/14 btdc/stock exhaust manifold on 87 octane and had to lower the timing and run 89 octane after he got his OBX header. Oh well, just some stuff to think about.

And yeah, the stock CR is 9.2:1.

 

[CRE]

I thought that was about where the stock compression was... I'm just having a hard time seeing how a .5 bump along with +3º advance would cause such bad knock problems... I guess I'm spoiled by the high altitude here. I'm probably at 9.3:1 or 9.4:1, 17.5º BTDC and run 85 octane.

 

[Tanya]

CRE, I don't think it's just the compression, timing and octane... seriously thinking my ECU is screwing up, possibly the electronic spark advance is frying at high load. I don't know yet. I don't ever hear detonation on the street, but I could be deaf too. I will be changing out the ECU soon so no worries.

 

[CRE]

Well, whatever it is I hope you track it down without too much hassle.


I really need to get a current dyno on my car.

 

[cuel]

The header was my last "bolt-on" engine upgrade. I already had the intake and exhaust done. I wasn't getting a bad knock, just a light ping under WOT. That was in the summer here. 95+ degree days, with high humidity levels. I just bumped up to 89 octane(instead of 87), and set my timing to... don't remember. Think I had it at 14, and dropped back to 10. No more ping. For having 210,000 mi.'s on all stock internals, it runs pretty good this way. I really do need to get back on my motor build, though. Need more days in the week...

 

[AJ'S 88NA]

The header was my last "bolt-on" engine upgrade. I already had the intake and exhaust done. I wasn't getting a bad knock, just a light ping under WOT. That was in the summer here. 95+ degree days, with high humidity levels. I just bumped up to 89 octane(instead of 87), and set my timing to... don't remember. Think I had it at 14, and dropped back to 10. No more ping. For having 210,000 mi.'s on all stock internals, it runs pretty good this way. I really do need to get back on my motor build, though. Need more days in the week...

For 210,000 miles to be running at all is good
CRE is getting away with 85 octane and 17.5 deg BTDC:aigo:. Must be the Maft-Pro.

 

[cuel]

Especially the way I drive...

I should try to tweak the timing a bit, and see if I can run 87 again. It would be a little easier on the wallet right now...

 

[AJ'S 88NA]

Especially the way I drive...

I should try to tweak the timing a bit, and see if I can run 87 again. It would be a little easier on the wallet right now...

Isn't it true that a high mileage motor may "ping" and to get rid of that you may have to up the octane?

 

[SupraMaster]

Isn't it true that a high mileage motor may "ping" and to get rid of that you may have to up the octane?

Or mess with the timing.

 

[CRE]

Or mess with the timing.

Or clean the 20 years of carbon build up off the pistons.

 

[AJ'S 88NA]

Or clean the 20 years of carbon build up off the pistons.

Don't they make some "snake oil" to do that

 

[CRE]

Don't they make some "snake oil" to do that

Yup, seafoam... aka naptha. If you don't like your seals I'd go buy some.

There are plenty of viable products which will help, but on an old car with a lot of build up you're going to be using a lot and over a significant period of time... better off just completely cleaning them out when you do the HG and THEN use an occasional additive to keep them clean.

 

[Tanya]

The trick is, to try to get a BHG in every cylinder so the engine cleans your pistons for you! :sarcasm: :biglaugh:

 

[castrol supra]

My 91 had an 8th an inch of crap on all the pistons.

I cleaned them up with gasoline and pb blaster.

I did this for days..., just soaking them in this mess.

They turned out well but not spotless.

It's kind of like your favorite glass pipe and trying to clean it after all the gunk sets up.
Only you can't use salt and hand sanitizer on the engine.

 

[jdub]

The only decent fuel additives are those containing polyether amine...Chevron Techron (Concentrate), GumOut Regane, and Red Line SI-I all contain about 40% PEA. I run a bottle through the tank every 5000 miles or so.

If you want to clean your combustion chambers, good ole H2O works really well. You'll need some vac line, a quart bottle and a needle valve. Just hook the needle valve with some vac line to one of the vac connections on the intake. Put another piece of vac line on the other end of the needle valve and place in the quart bottle of water...feather the throttle between 1000-2000 rpm till the bottle is empty. Basically you steam clean the pistons and valves...I do this once a year

 

[CRE]

Water FTMFGDBAWMF!!!!! :biglaugh:

 

[jdub]

LOL...it works really well too

The trick is to adjust the needle valve to the point where it just "studders" at idle, then close a 1/4 turn or so. This will give you the water flow you need.