quote:

Originally posted by Spanky@Wilson Race Engines:
I have stated before. These heads do not like Alky. But for the hell of it. Move the piston down in the hole .040 and get a custom piston to make uup the compression difference. This may help. Get the ring land away from the heat

I've heard this before about the SR20 heads, that they "don't like alky", but no one has been able to explain why. What is it they don't like? I've seen many other combos, including 18-9* stuff running well on alcohol...I'm just trying to learn more about this since I'm making the switch to alky this year.....

While on the Dyno you need to tune by the plug reads. Each cylinder will want its own jet. You might have several with the same jet but front to back the jet spread can be as much as 8-10 jet sizes. One cylinder will always become the picky one. It will be the one that burns a piston first. Once you get the jet and timing within range. Tune to your picky cylinder and all the rest will be happy. Large displacement motor don't really like alcohol because of port saturation of fuel. The more efficient the motor is the less gain you will see when changing to alcohol. Real efficient motor you will actual see a power loss when changing to alcohol. This centers around the port fuel saturation. When moving your tune up from the Dyno to the track. Most motors will want a little less fuel and a little more timing. The motor on the track will never see the kind of loading that it saw on the Dyno,...close in high gear though.

I run an Enderle hat on 454 SBC and while yours may not be the same I will tell you something interesting I learned. I have 8 O2 sensors on my Data Logger and found at the finish line the rear cylinders were running leaner. This did not show up on the dyno.
I think it is due to "Ram air effect" for rear cylinders and the fact that the air has to make a sharp turn for front cylinders. What I did was put larger nozzles on rear 4 cylinders. In the future I may build a hat riser with a diverter plate to force about half the air to the front.

So you should check your plugs after the run and if rear cylinders look leaner add more fuel to them.

Triple Nickel,

I don't think the primer plus had anything to do with it.

Sounds to me like too much timing in combination with a lean mixture. This is a dangerous scenario when using a fast burn combustion chamber like the SR20 heads have.

A lot of injection advice here but be careful because not everyone is comparing numbers correctly. Some of the combo's in this thread are using 0 1/2 pumps and others are using 1 pumps. BIG difference between in flow between those two pumps so can't compare tuneups. Also, some are talking about Ron's and others about Enderle. While the two behave similarly they still have differences when comparing tunes. With all else the same except pump size the #1 pump setup will need at least 30 numbers bigger pill than a 0 1/2 pump and it still will likely deliver more fuel to the engine.

Scott

I agree on the primer plus deal while it's not ideal fuel mix for breaking one in I am not real sure this is what caused the original issue. I did find that the way i had the water flowing in and out on the first trip to the dyno caused problems with the water flow. When it got hot and up to temperature, water was not flowing, and it was basically air locked. I fixed that this go around.

I did have 1 cylinder always about 100 degrees cooler that was #2. It just always had lower egts. It didn't do that on gas. Possibly one jet just a tad too big.

In the first trip to the dyno, the timing was much higher starting out at 28 and moving up to 32. 2ND trip to dyno started at 25 and moved up to 28 then back down to 27. Stayed out of the 30s completely. It was locked in at 1090 hp and needed either a timing change or something significant to make it move cause all the main pills and high speed attempts just sorta moved a few hp here and there.

All in all I'm interested in seeing what it will run and if it will be a good combo once it's all sorted out and in the car. It will be a few months though it's a total fresh build on an old car so I still have a ton of work to do (wiring, plumbing, repaint, etc.)

Ron, we did read the plugs each pull. Timing mark was right in the curve but couldn't get the plugs to show any major signs of heat. I was hoping for about 3/4 to full burn onbthe bottom ring of the plugs, ran out of NGKS and those autolites don't burn as easy as the ngks. Will get more onow it's in the car and see what it likes. Thanks for all the help and advise.

555,
2 pennies.
1: I can't see the primer thing being used for break in. It can only be tuned for x rpm and one timing point. Up or down from that point and chaos ensues. I wonder if the hurt began there and it did not become obvious until full pulls.

2: When you get to the track follow alky rule 1. When in doubt richen up first.

3: As noted, fast burn heads require way less timing than assumed and sometimes way more fuel than sounds reasonable.

4: Agree that anything beyond 14:1 on NA alky gains little if anything and sometimes goes backwards. The tuning window does get insanely small. Solutions are to "soften" the chambers or drop compression.

One thing I did not see on your original queries was the altitude and weather you were testing in.
Here in IA/IL/IN/OH your tune would be a reasonable starting point for an average sticky day with non fast burn heads.
You are in Louisiana, correct?
I assume lower altitude and not so sticky in March?

This message has been edited. Last edited by: Dave Koehler,

quote:

Originally posted by Triple Nickel:
Ron, we did read the plugs each pull. Timing mark was right in the curve but couldn't get the plugs to show any major signs of heat. I was hoping for about 3/4 to full burn onbthe bottom ring of the plugs, ran out of NGKS and those autolites don't burn as easy as the ngks. Will get more onow it's in the car and see what it likes. Thanks for all the help and advise.

..I prefer the NGK's for reading. If the plug is reading fat, then pull a couple of degrees and pull 5 out of the fuel and read, then another 5 if needed. 5 does not show much until you get close to what it really wants. Also look for your pecky cylinder, it will read lean first. I usually if adding jet to a cylinder take jet away from a fat cylinder. You should have a calculated total jet area for all jets. Try to stay close to that so pump pressure remains the same.

Dave,

1. I spent many nights thinking about how the primer deal might have started some of this problem, i agree its definitely a potential, no real way of knowing as power was consistent on all 3 pulls that day but TQ on the burned piston day was down about 20 ft lbs from the second attempt. Future builds will all start up on gasoline carb or just go directly to alky and forget the whole break in deal.
2. Agreed, plus some new NGK's.
3. Agreed again, the dyno is a good place to be when working one of these combos out. Wish i had started with timing much lower and had water going the right direction, that would have eliminated at least 2 potential causes on the initial trip to the dyno.
4. Interesting to note that the tq came up to 900 for round 2 on the initial pull and were able to see 908 later in the day. This is with 1.3# less compression ratio. Initially it was 16.0:1, added in 0.030 more head gasket (14.7:1 now) and rebuilt it with same parts and pieces (aside from moving to higher tension oil control ring) and it lived on the dyno plus it made more torque.

I need to go back and look at the exact weather but it was nasty hot, and yes, south louisiana. Temps were above 90 during the day and down to upper 80's later in the evening. Our last pull was at 8 pm, but it was still hot as heck outside. Baro was low (if i remember dyno operators comments correctly) but most definitely weather will be different when the cooler temps roll around. The weather was very similar for the first attempt when we burned a piston but Baro was a tad higher, but correction factors were in the ball park from each other. Day 1 was NOT wonderful weather, it was humid and hot, but more Baro. 2nd attempt was lower Baro, dryer air, higher temps. If i had to guess DA was well north of 1500 for both days.

I do the initial start on mine every year with the primer plus because it builds heat quickly and no risk of washing the rings or milking the oil. Granted it is not a tunnel ram with a hat but all a carb does at idle is "drip" fuel from each blade anyway. I do use 110 octane race fuel though.

Scott

quote:

Originally posted by Dave Koehler:

3: As noted, fast burn heads require way less timing than assumed and sometimes way more fuel than sounds reasonable.

4: Agree that anything beyond 14:1 on NA alky gains little if anything and sometimes goes backwards. The tuning window does get insanely small. Solutions are to "soften" the chambers or drop compression.

?

Dave,

I like the we "think" the same on this. To me these high-end, fancy cylinder head, fast burn chamber, high compression, big CI engines on alky sometimes behave like and need to be treated like a heavy nitrous engine.

Scott

I've got another question. Regarding compression ratio. I've been told alky loves compression. Here you're saying that's not necessarily the case. Please elaborate. Trying to learn as much as I can since I'm making the switch later this year

Mark,
That saying dates back to the 60s and even the 70s.
At that point in time a BBC with 4" stroke and 4.375 bore was "BIG" and had a hard time creating 13.8:1.
Small, shallow chamber heads had not even been dreamed up yet.

Look where we are today with strokes and compression is in diesel territory.

I have never sat down and done the deep math but I suspect part of the problem is that alky requires more volume space than gas. We may have inadvertently created a cork.

I might also add that feedback from those that got past the "gas makes more power" mantra stumbling block and did the previously mentioned procedures and tuning would invariably find that missing power.

Dave said it better than I would have. Here’s my worthless two cents on your deal Mark.

I would try to keep the compression down some since the whole idea for you is that you’re going to spray it in order to burn more fuel.

I loved my alky setup but on your deal I would err on the cautious side. Since you’re down in Induction Solutions part of the world why don’t you see what he says. Just a thought.

Vern, gonna have Steve add the extra bungs on my intake. As to the bottle, he's not big on alky/alky for nitrous.

Dave, in your opinion, do you think the gas makes more power statement is due to lack of development on alky combos? What I'm starting to find is that while gas may be the fuel of choice pretty much by the majority of builders, unless I'm way off base, alky can and will make more power if the combo is made for it, just like one optimized for gas. Thoughts?

My thoughts on gas only with n2o?
Kind of like the compression thing Gas is all most people know so.......

Look here for what is possible.
https://www.koehlerinjection.c...charger-alcohol.html

IF the site gives you some warning about being unsecure, ignore it and go in.
I'm am growling at my host about it.
Did the same thing last year at this time.

I mean alky vs gas combos in general. I think there is a lot of misinformation out there, especially with nitrous/alky combos

My thoughts on it are pretty transparent if you see my web site.

Now, here is something for everyone to mull over.
Don't knee jerk respond.
Give it some thought first.
I saw this on another site in bold.
What can you determine from the following statement?
"You will net more HP from the same jet on all Gas."

This message has been edited. Last edited by: Dave Koehler,

quote:

Originally posted by Dave Koehler:

"You will net more HP from the same jet on all Gas."

I’ve never seen an alky nitrous combo put down an impressive number for a given jet unless you’re talking about just a little nitrous.

Maybe Scott can share JMOs T/D combo but I bet it doesn’t knock your socks off compared to what others have ran on gas with that same pill.

BJ,
That is the popular I have never reply.
What I am asking everyone to do is step back and analyze that sentence.
What do you see/deduce/suspect/conclude?