myfast70

iTrader: (38)

I am wondering what type of gas you guys are running (brand and type). Have any of you ever had issues with tuliping or ruining valves? The reason why I ask is that we've seen some issues with local turbo Buicks. It seems that the guys that are running over 20psi are starting to have valve and engine issues.

The weird part about it all is that everything seems to be perfect with the engines and the tunes. For instance, one guy a few weeks ago tuliped the valves one cylinder #1. He has a FAST system in the car (just like the other two that have had issues) and logs showed everything to be perfect. The afr's were at 11.6-11.8 the whole run, the EGT's were in the low 1300's and the computer wasn't adding any any fuel and was actually taking away 1-3% during the run. He was running just shy of 24psi throughout the run. The car was idling a bit funny after the last run and when we checked the EGT's at idle cyl #1 was down about 200* compared to the rest

The next guy ended up losing a motor this weekend and we think it was due to the same issues as above just a whole lot worse. We ran the valves on Friday before the races and they were perfect. We then made a pass on Saturday at 20 psi and everything seemed to be ok so we upped the boost to 24 psi and then the problems started. We noticed that the engine idled a bit rough as the other one so we decided to check the vlaves and found that they had tightened up and had minimal lash so we reset them and made another pass and that's when the motor blew We checked the log on that pass and up until it blew everything was perfect with it!! It was at a steady 11.6 afr from start to finish and was not adding any fuel at all. These engines were idetical builds and usually run consistent 9.40's to 9.60's. We pulled the valve covers off today and found all of the intakes to be about 1/2" taller than the exhausts The valves in both engines were hi temp stainless valves.

Now here is where things get weird. We are building a low 8 sec car for a guy and this car has a lot bigger turbo (96mm vs. 70's). This engine has Ferrea Super Alloy valves in it and they also ended up tuliping and cyl #'s 1 & 5 ended up lightly burning the pistons Same thing as far as the tune goes, spot on the whole time and never over 20psi of boost.

Now the commom thing between all of these engines is that they all run on Sunoco Maximal 116 octane fuel. We were told that it is possible that we have exceeded the limits of this fuel and that may be the cause of all the engine problems we've been having. They are thinking that the combustion chambers temps are getting so high that it is tuliping the valves and burned the two pistons. We were told that we should switch to something like Q16 or a NO2 fuel or even VP Import fuel. What are you guys running when running over 20 psi of boost? Have you ever heard of these issues before? Any help would be greatly appreciated because this is getting really frustrating. We know that it is not a tuning problem, not an engine builder problem and now with two different types of valves not a manufacturer problem.

elias_799

iTrader: (8)

well it depends on what CR you have as far as what gas you should be using. what is the cr in those motors ?

myfast70

iTrader: (38)

8:1

I just looked at VP's website and it shows that VP Import Fuel "works well under high temperatures due to mechanical heat". There is another local guy with an 8 second GN and he runs the Import fuel and he has never had any of the issues that the above engines have had. I'm thinking its got to be worth a try, afterall, look how much boost some of those little damn engines run.

barnat

iTrader: (59)

LOL I was running 30PSI on my 8 to 1CR stage ll, 87 GN with no problems at all. Was kinda dodish out the hole when compared to the stock 3.8 For a secound or so lol But held together ALOT better and far more top end too, but had good heads also

crashly

firstly,
i run methanol , not gas...But this is what i have found.
i have seen my exhaust valves "walk" , if the tune is not spot on.
the seat sealing area , moves abit.. remove them and a very , very light lap , all good.
not the way to do it , if you have cnc cut valve seats tho...


the extra heat you are seeing in the egt , 1300 F , is a bit high for my liking too.
the intake valve is tuliped too ??
that does show you have too much cylinder temp
you may have to drop the a/f ratio down a bit
maybe the 'spot on tune' , is a tad lean.....
the engine is trying to "tell you something",
what does the top half of the big end bearing look like ????

speak to your engine builder / or others in the industry , and may require a better quality valve.

ash

myfast70

iTrader: (38)

What were you running for gas?


BTW, on the second engine posted above, it had tuliped all of the intakes and the exhaust valves looked to be fine.

cablebandit

iTrader: (37)

I would use vp c-16 myself

Sluggish

iTrader: (10)

What about Q-16?

pmbmax

it is Oxygenated but is 116 octain. made by VP

pmbmax

I run over 25psi on VP C16 I dont think any other fuel comes close to C16 in boosted aplications i have helped tune on cars that have heads that flow over 400cfms and are 427 cubis inches and run over 50 psi and have never had a fuel issue. Not trying to be bias but thats what works in real world aplications . It is a little higher than other stuff but it is cheaper than engine parts The drum i picked up last week was a little over 600$ for 54 gal or it is around 12.00 a gal .

Qwick98Z

If it tuliped the valve thats telling me the cylinders are getting to hot, I would try to find a fuel that would have the best cooling effect on the cylinder.

myfast70

iTrader: (38)

It looks like they are going to e trying out the VP Q16 fuel and see if that takes care of the issues.

Has anyone had any issues with the Sunoco brand fuel in general?

Sandmann120

iTrader: (1)

It makes me wonder why more people don't run methanol in a setup like this, even as a supplement.

chuntington101

hate to highjack the thread but have you any details on this?? sounds like...fun!

Chris.

pmbmax

It is BB and Ts old set up and the engine was or is in Shannon Wrens mustang . the other is in Jim mills car which is bb and t s old white car http://www.bbandtracing.com/ they where both ford engines brodix neal heads.

pmbmax

It would be harder to tune with the Q than C. If you ask me those number are lean at above 25 psi . What i would look at first is what is inlet air temps . If you are at the limits of the intercooler are the compressor you could have gained heat on inlet . When you start running big boost , They inlet air need to cool and afr fat . Thats the only thing that is going to keep the cylinder cool. just what we have found

myfast70

iTrader: (38)

Inlet air temps were 105 to 118 max during all runs. The first runs on both cars were low 11's.