100% methanol engines don’t pepper a plug, its either detonation free or there’s a hole somewhere with very little in between.

I shouldn’t say there are zero signs with e85. But I’ve never seen a peppered plug running it. On my pump gas stuff I’d get a clear light peppering on the plug when I got into a little detonation. I’ve popped a few HG’s on e85 on 4-5 different engine platforms. Never seen any sign of speckling/peppering on e85.

The engine was clearly detonating on both pics, but neither caused any kind of engine failure. Kinda surprised I didn’t break something on that bottom plug tune. That was the tune in the car when I bought it. Got it home and found that when I pulled the plug.

Light pump gas detonation



Heavy pump gas detonation



Both these plugs were pulled from running engines with no HG issues, but clearly were detonating. I've also seen this with race gas. I’ve never seen anything remotely resembling this on E85.

 

So I was reading where some use arp head studs part number 154-4004 for 1/2" studs...

Just leave the head on and pull out one stud at a time and run a 1/2" tap down to the pre-marked spot on the tap and then using those 1/2" studs for a better bite into the aluminum block... also for more rigidity coming up through the head hole itself .. ?? I understand it necessarily wont help with straight up holding pressure much ... but I would think it would help with longevity... ?

thoughts ?

Does anyone think there is a "pre-forming" size I could use before just re-tapping it to the 1/2" size ? what size are the current threads in the block ? 11 mm ? wont the 1/2 tap just reshape it without drilling... with lube of course ?

 

The hole still needs to be at the minor diameter of the tap, not to mention you don't want to leave all those shavings in the engine even if it is possible

 

11 mm major diameter is 0.4350 in . 1/2 20 thread minor is 0.4250. aproximately. mathematically it should work.

im keeping head on... one at a time.... no mess in the cylinder.... ??

 

Can anyone tell me the limits of this kind of fuel ? With my setup not being maxed out on boost yet, would 30 psi on this setup be "impossible" with E85 ? What number boost should I call it quits and go to another fuel ?

I only ask because my pulleys are not adjustable... its a long story... but I cant really lower the boost any.

Also what are the limits of this LS2 block ? I do have a spare 5.3 that's been stroked to a 393 with blower pistons... but was trying to keep the car light ... Am I in territory where I should switch over to iron ?

I am trying to compete with Lamborghini V12 and GTR setups... is it even possible ? ... would the iron offer any advantages that offset the extra 90 lbs?

 

I think the fuel will be OK but the block/heads will not. I see you are hitting 15psi at 4k RPM with an F3R. That is definitely 6 bolt head territory. You can keep the Aluminum block if you get it sleeved and worked on by someone like ERL to convert to 6 bolt heads. You can definitely compete with Lambos and GTRs with that much blower considering it will push 2000+. Just have to spend the $$ to build the car around that blower.

 

ok, its been a year... I have had the engine apart and since installed 1/2in studs, ls9 head gasket, resurfaced heads, installed titanium valves, and am now making my own e98 fuel with ethanol and 93 octane .... and resigned up to run again jan 21st

 

here is my new timing table ...? is this a start to try from?

 

also.... using the gas scale.... is this a good target for my afr running e98 ?

 

at minimum... can anyone at least verify this is a good target goal for ethanol on the gas scale..... holley doesnt have any preconfigured ethanol graphs and i want to eat at least one gtr that saturday

 

Can you explain what you did to use the 1/2"studs?

 

sure... i pulled a head, put it in a 90degree drill press and drilled out 1/2" holes where the head studs were... then put in a 1/2 in tap bit with the drill in "reverse", used it to ream the hole out to exactly 1/2". then i painter taped up the deck surface (coolant passages) and oil valley area and put the head back on. i used the drilled head holes to guide the 1/2 in bit a measured distance to the thread start and stopped... then i got a super long i think it was 27/64 bit from ebay ...drilled it to the bottom.... then 1/2 in tapped new threads....


VERY IMPORTANT ... before the final tap... put your drill in "reverse" with the 1/2 in tap and run it down as a reaming tool.... before you retap the bottom threads..... much easier on those oversized studs with that black coating on them they are just over 1/2 in.

edit : i did two of these blocks... one aluminum and one steel. the aluminum one i did not drill the bottom threads.... i just slowly and with lube... tapped through the old threads since it went easy.... the iron block threads would not cut as easy though so i drilled those.

also i purchased two 1/2 in taps... one of them i cut the end off of it where the tap tapers down.... i tried to give it a sharp edge and run it down last to get the very most out of the bottom of the hole... i used a 16 point 1/4"drive socket (5/16 or 8mm size) with an extension to get my tap to the bottom of the hole.. and used a 16v dewalt drill on it setup at half power so i didnt break it off in the hole. rocking it forward and backward until it hit bottom.

the aluminum block went really easy... the iron block had trouble... at about the 10th hole the tap broke off... i got it out... but i will not be tapping an iron block ever again.

the stud strength isnt even comparable.... the 1/2 in stud is so much more rigid than the stock studs. tightening them down in the car i couldnt make my wrench click without climbing into the back of the car to get enough leverage on it.