What is the limit of boost able to be run on E85 with stock block and no head studs?

 

That's a loaded question. There are still relatively few people running around with E85 conversions, and most of these people have been running E85 for less than a year, so the long term effects of high boost with E85 are basically unknown. With that said, with the stock turbo its pretty common to aim for 28 psi peak and then take whatever boost you can get out at higher rpm, usually around 23-24 psi at 6000 rpm with rapid taper after that due to the limit of the turbo.

 

Thanks for the input. That range is kinda what I was expecting but just wanted to be sure. Off topic, but for scaling 1000cc injectors is 608ish correct? Or is there an area in between say 600 and 615 or whatever? Just need to get it close so when I install the injectors, I can drive around for a day or two before the tune and let the tuner do the rest of the work.

 

28 psi

 

I am running on a totally stock shortblock at 30psi and have for longer than the time I have been on E85/98. I have tuned some larger turbo cars that run 28-30 on little more than rod bolts and not even headstuds. I think some of the problems with headstuds were do to tune and not so much pressure in the cylinder. Rod bolts are however inexpensive insurance against failure at high boost and high rpm.

 

There are a few cars around me that run 30 pounds daily with no issues with only rod bolts. and in all reality there is still room to turn up the boost.

 

Awesome news- thanks guys. Any input on the injector scaling?

 

28 psi for street, 25psi for road course tracks.

 

Injector scaling is dependent on AF and trims measured and is ballpark 30 percent lower than the scaling number you might currently have and then fine tuned by making sure your fuel trims are in line.

First tank of e85 as an example is different from the second tank on due to residual gas being in tank and fuel system.

 

30psi seems like a lot on the stock head bolts. I wouldn't risk more than 25-26psi if its completly stock..

 

I spike 27psi and I still have stock headstuds.

 

There are a ton of people that run more boost on pump then that. 30 on e85 and stock head studs is fine.

 

Right on.. We just havn't really pushed the factory bolts too much i guess.. Most of the E-85 guys here just do them when we do the conversion just like somebody said its cheap insurance...

 

I have been running the guinea pig on my car just to see if its a myth and where it becomes reality. One reason I havent even put the rod bolts in even though there have been failures at less boost and power than I am making.

Of the 3 cars that we have been testing:

2- are on E85 and running 28+ psi daily. In fact I think both of us are at 30 now (not sure about the other car). I am on a Green/S2 and the other is 57 trim/stock cams.

1- is on straight pump at 26-27psi spike with stock IX/280s.

We all have big intercoolers and good NW air.

Mike and I are running about the same timing (see the E85 tuning notes for a shot of his timing map) and the pumpgas car is about 10-11* out the top by comparison (stock IX turbo).

The pumpgas car and I are both also on stock rod bolts and have over 25,000 miles at this level so I would say its a confirmed kill on the headstud theory at least on a stock compression and smaller turbos. Lucas has had intermittent issues with his 10:1 motor at that level but we think its not head studs as much as the block needs decked (maybe this winter).

I wouldnt try this on a 35r or larger car, but even the 30R HTA we just did doesnt seem to have any issues.

Take it for what its worth though as your results may vary.

aaron

 

Thats good info to know.. We just really havn't ever experimented with how far they will go..

I pushed the rod bolts on my car to 468HP and low 11's@125-127@ altitude.. But the head bolts are what i was always worried about. I swapped them before i had to chance to really push the factory ones to far... But it sounds like you and several others have pushed them pretty far with success.. Maybe thats something we will try..

Thanks for the info!!
Mark