FI build questions

**98TransAmWs-6** · 06-05-2011, 11:37 AM

I am looking at getting a procharger at some point and I don't really know anything about what makes a good FI build so I have some questions. For an FI build is it better to go with smaller displacement block like the ls1 or could you go with large displacement like the lsx 454 and have even more power? Besides of how FI works I really have no idea what makes a good FI motor. So I guess my question would be what would make the best lsx FI motor?

**Double0me** · 06-06-2011, 01:36 PM

whats your end goal(HP)? Type of setup ie Drag, Auto cross....?

**98TransAmWs-6** · 06-06-2011, 02:24 PM

Originally Posted by Double0me

whats your end goal(HP)? Type of setup ie Drag, Auto cross....?

Well the ultimate goal, when everything is done to support the power, is to be in the neighborhood of 800+, the type of racing is going to be a mixture of the two but my suspension is going to be set up for autox for most of the time.

I forget where I read it but some information I got said that small blocks are typically better for FI. I don't know how true that is.

**35th-ANV-SS** · 06-06-2011, 02:43 PM

That is correct. Large displacement motors are more geared for NA. Small displacement is more geared for FI.

I have a build thread of my Procharger build in the FI section of the site if you'd like to check it out for some general information.

I'm not going nearly as big as what you are, but there is some decent info in there.

**Double0me** · 06-06-2011, 03:44 PM

Originally Posted by 35th-ANV-SS

That is correct. Large displacement motors are more geared for NA. Small displacement is more geared for FI.

I have a build thread of my Procharger build in the FI section of the site if you'd like to check it out for some general information.

I'm not going nearly as big as what you are, but there is some decent info in there.

+1 I read it before I started mine, LOL.

**98TransAmWs-6** · 06-06-2011, 05:46 PM

Originally Posted by 35th-ANV-SS

That is correct. Large displacement motors are more geared for NA. Small displacement is more geared for FI.

I have a build thread of my Procharger build in the FI section of the site if you'd like to check it out for some general information.

I'm not going nearly as big as what you are, but there is some decent info in there.

Yes I have read a lot of it. That is what geared me to ask this question. Another displacement question, at some point probably before I get the procharger I am going to get a block and forged internals, what block would be best for pushing it to the limits? I was figuring a iron block but I don't know if that is necessary. Also should I get a bigger than stock crank to stroke it out or would I just be better off with stock sized crank?

**See Me In My GTP** · 06-08-2011, 12:08 PM

I'm no expert, but I've seen 390ci and 408ci motors run those power levels and beyond. An F-series ProCharger at high boost should hit 800rwhp. I'd recommend you start your research with AES or a similar builder to at least get a sense of what's needed and what a reliable setup consists of.

Their 390:

3.800" crankshaft
6.125" rod
4.030" bore size

Shorter stroke will allow for a thicker ring land and increased journal overlap from what I've read. To be honest though, I can't imagine autocrossing an 800rwhp car. I'm WELL beneath that and things get hairy in a straight line at times.

Again, I'm certainly no expert on builds of this caliber, but hopefully I haven't mistated anything and provided decent information to start.

**98TransAmWs-6** · 06-08-2011, 01:12 PM

Originally Posted by See Me In My GTP

I'm no expert, but I've seen 390ci and 408ci motors run those power levels and beyond. An F-series ProCharger at high boost should hit 800rwhp. I'd recommend you start your research with AES or a similar builder to at least get a sense of what's needed and what a reliable setup consists of.

Their 390:

3.800" crankshaft
6.125" rod
4.030" bore size

Shorter stroke will allow for a thicker ring land and increased journal overlap from what I've read. To be honest though, I can't imagine autocrossing an 800rwhp car. I'm WELL beneath that and things get hairy in a straight line at times.

Again, I'm certainly no expert on builds of this caliber, but hopefully I haven't mistated anything and provided decent information to start.

Thanks for the info, I'll definitely check AES out to see what would be best for me.