Some more knowledge for building a short block

[Stew Pidaso]

So I have been doing many nights of reading because I am continuing with my build and this winter is finally time to do the bottom end and I have my pistons selected (wiseco 10:1) but am still contemplating for the rod to choose. I've heard that 10:1 is a good CR for e85 which is the fuel I plan to use but how much more in depth is tuning with a higher CR. I may not be posting in the correct forum for that topic but I'm just trying to get more in depth knowledge on the short block. What sort of power is possible to achieve in a build like this and what's pushing the limits too far. I'm just trying to get as much information as I can before I start. Thanks guys

 

[BogusSVO]

Stock blocks and cranks have gone 1000hp, with proper machining, assembly and tune.

10:1 Cr is going to be different in the tune as far as pump gas and E85 and knock.

No matter what parts are selected, and how much cash is spent, if you have a cruddy tune, you will fry the engine before you are out the driveway.

Instead of wondering what the max HP you can make is, set your goal and work towards that.

Drop a 800hp engine in the stock car, you will just break parts every time you turn the key.

I can understand you want room to grow on the build, so for example, shoot for 400-500 HP but build the engine for the 600-700 hp range.

For about the 400-600 range, about any decent H beam will work, after 500-700 Turbo tuffs should carry you there.

 

[TSicktalon]

Since you're using corn juice, the CR shouldn't be as much of an issue as with pump gas. Ethanol is VERY forgiving compared to gas. Still need to tune it properly and learn the differences between the two, but it makes great hp. You'll need to elaborate on your setup and how much power you are shooting for to get any ideas for your other concerns.

 

[Stew Pidaso]

well for starters i would like to max the boost out on the turbo when the short block is completed (not rightaway...graduallyand with tuning) because I know that a stock block wont hold that much from what I've heard and read. I was thinking hp in the 600's with everything done correctly tune-wise but I also dont know the limits of the turbo. Im sure the HX-40 has no problem seeing 40psi but the max ill be able to take it for now is about 35 with this wastegate spring so I was hoping for in the 600's with max boost with this spring. Maybe 700+ hp could come in the future but for now I'd like to see around 600 and then some room to grow like Bogus said. Also I forgot to add that I'd like to rev to about 9k and I've heard thats do-able without going to aluminum rods. Any input on that?

 

[JacksonAuto]

E85 requires higher compression for max efficiency. If you plan to run E85 all the time you'll want to build the engine around 10.5:1. If it will ever see pump gas it will be too much compression and you'll get knock. You'll need to make up your mind on pump or E85. While you can build it with lower compression and run both fuels, you'll sacrifice performance. It's like a Swiss Army Knife- does a lot of things but none of them well. With the higher compression we always recommend an billet rod. The h-beams just aren't up to the task. Piston wise it's Wiseco HD, Venolia or Manley Platinum Series.

Tuning wise, higher compression doesn't make it more difficult to tune. When using the correct fuel for the application, higher compression is actually easier to tune because the engine is burning the fuel more efficiently. Now if you were to build a 9:1 engine and try to tune it on E85 it will give you fits for days and never really run right.

 

[Stew Pidaso]

It's definitely an e85 only build. Also what sort of break in time do you normally give to a bottom end or is it kind of your own personal standard and when I get into some high rpm tuning after its broken in, should I start with my map or should I drop timing a bit and bring it up from there.

 

[RWD4G63]

It's definitely an e85 only build. Also what sort of break in time do you normally give to a bottom end or is it kind of your own personal standard and when I get into some high rpm tuning after its broken in, should I start with my map or should I drop timing a bit and bring it up from there.

We break our engines in like this:

Start up, warm up, check for leaks, etc.

Put it on the dyno, do some mild rev pulls to get the tuning roughed in.

Then we do power pulls.

We've never had an issue.

I would also tend to disagree with Jackson about the compression ratio, if you have lower compression you just run more boost to make the same power. We've tuned plenty of E85 cars on 8.5:1 compression that run just fine. Higher compression isn't going to make it start any faster in the winter .

Higher compression is really only necessary (IMO) if you are not octane limited (Q16 or Methanol), and you're looking to absolutely max a certain size turbocharger.

 

[JacksonAuto]

They'll run on lower CR, just not as efficiently. Plus you're leaving a lot on the table. If you know you're going to run E85 all the time why would you want to build it with a lower CR? Sure you could lower the CR and crank up the boost to compensate but many (if not most) people don't have a cylinder head that will support that kind of flow, and it's not as efficient. High compression has a lot of advantages and the limiting factor is usually fuel. You're planning to run a fuel that allows high CR- a lot of customers would kill for that so why not take advantage of it?

 

[Stew Pidaso]

Yeah that's what I was trying to do was maximize the engines capabilities not having to compensate for more boost with less compression and stuff like that. I guess I'm not quite there with Jackson's 10.5 CR but I just got these pistons through a deal with a guy I work with and I couldn't turn it down or I may have gone higher compression wise. I would like to max the turbo out as I've said before but that will come in due time and I won't have to max it out too fast with no room to grow since its not a smaller compression is what I'm getting from this thread so that good. I don't know personally if ill be doing power pulls and stuff right off the bat like rwd said but maybe I can get some dyno time if I'm lucky and able to do tuning there.

 

[WES_393]

I don't know personally if ill be doing power pulls and stuff right off the bat like rwd said but maybe I can get some dyno time if I'm lucky and able to do tuning there.

I'd highly suggest doing so. An easy break in won't do the engine any favors.

 

[-red97rum-]

Now if you were to build a 9:1 engine and try to tune it on E85 it will give you fits for days and never really run right.

I can see what you mean on the efficiency aspect with E85 and higher compression. Now as to the degree of real world gains, until actual results are measured, in my opinion it's a moot point.

The statement you posted above simply isn't true. I've been running E85 for a number of years now, through a couple different engine configurations and it never gave me "fits for days." Hell, I've been running e85 through an oem 7.8:1 6 bolt I paid a $100 for, with god knows how many miles on it and it runs just fine. AFR's are steady, it's gone 7.0@100mph (auto trans) multiple times so it's was making plenty of power.

Another example is one of my best friends. His 1G with a 9.0:1 wiseco/eagle combo has been putting down over 600whp on RRE's dynopak with an off the shelf 35r for well over a year now. There's plenty of other examples out there where a 9:1 engine has achieved great results on E85.

I just don't want what you said to mislead anyone into thinking their car, by default, is going to run like shit on ethanol if they don't have at least 10:1 compression. I get what you're saying and maybe you didn't intend for it to come across so "matter of fact" but that's the way I read it; no disrespect meant towards you guys.

 

[Stew Pidaso]

I'd highly suggest doing so. An easy break in won't do the engine any favors.

So you don't think putting a couple miles on it is better? Just making sure

Also rum what boost level is your friend getting these numbers with. I'm assuming its e85 as well.

 

[-red97rum-]

So you don't think putting a couple miles on it is better? Just making sure

Also rum what boost level is your friend getting these numbers with. I'm assuming its e85 as well.

Yes, he's running e85, he made 604 at this years MOD right around 33psi

[ame=http://www.youtube.com/watch?v=ggxRpaWgJns]2013 MOD 1G DSM Dyno - YouTube[/ame]

 

[JacksonAuto]

I don't follow the logic here. If you plan to run E85 why would you want to build a lower compression engine and leave power on the table? The only downside to higher compression is that it's often fuel-limited which doesn't apply here with the use of E85. More power at lower boost is win-win. Compression increases the efficiency which in turn increases reliability and makes the engine easier to tune. There are no downsides.

 

[Stew Pidaso]

Well i dont think 10:1 compression is low especially for e85 thats why i chose that set