Custom Crossover Course ---PROGRESS---

TGed · February 10, 2009, 07:51:37 PM

I am thinking about building a crossover for a semi stock 3.1 N/A engine what will become boosted with potential upgrades & I'd like to pick some minds here.

The size tubing I'd like to run is 2" from each bank using the stock TGP manifolds joining to 2.25" or 2.5" collector going to a T3 flange then to the turbo of choice...

There is no turbocharger in mind currently, but t3 journal bearing something is the area of interest. Not going with anything smaller. Bigger? Maybe!

I know with too big of volume you could lose heat, velocity, and then power/lag. The thing I am trying to avoid is using too small of a dia in which might hurt possible future upgrades (Port work, valve sizing, turbo hybrid combination's, etc etc) . I kind of want to do this right the first time so I don't have to re-engineer what I come up with now.
Putting up with some future alterations is fine, I just don't want to have too many needed changes that will put the build-up at idle for too long...... Summer is too short as it is!

I know some would suggest going gun ho now, but I'd like to MAYBE see the before and after of this custom creation.
Discuss.

TGed · February 18, 2009, 09:06:00 AM

Wow, no one has experimented with this before?

mfewtrail · February 18, 2009, 11:05:12 PM

Quote from: TGed on February 18, 2009, 09:06:00 AM
Wow, no one has experimented with this before?

If we had, most of us wouldn't still be on the stock turbo. ;) I know 300whp has been made through the stock x-over with a larger turbocharger installed...so it can at least support that amount of power. I don't think you need to go a whole lot bigger even if you're after a lot of power considering what can be pushed through the puny stock x-over. I'd maybe take a look at what the 3X00 turbo guys are running in J-bodies, etc., I know several of them are making pretty good power these days.

TGed · February 19, 2009, 08:57:28 AM

I've read and looked at a few threads about a lot of 660 owners making crossovers. Most stay the same not giving it much thought. What I'd like to find out is the size of a set of 660 headers crossover. It would possibly give me some insight.

I just dont want to leave it stock IF I can gain some spool up time and reach peak power sooner. I think I am going to have to be Christopher Columbus on this one.

flybynite · February 19, 2009, 05:56:55 PM

Quote from: TGed on February 18, 2009, 09:06:00 AM
Wow, no one has experimented with this before?

I have found that it's best to have lots of velocity before the turbo. You achieve this best with smaller od pipe, Less lag.. After the turbo bigger is better... ;)

TGed · March 01, 2009, 11:29:58 AM

Well the pipes are ordered and I will be ready in about 2 weeks (about when they'll come in) .
15.00 shipped for 10 mandrel bent J bends, can we say DEAL. I'll leave the size unmentioned for now. Keep ya'll thinking!

I wrote the size down for the stock x-over somewhere around here, until I find where I put that note pad, does anyone know or can measure the stock size x-over for me now? Thanks in advance.

QuoteAfter the turbo bigger is better... Wink

I know that, that's what the 3.5" mandrel bends are for... Had those pipes since last year! lol

Now I just need to purchase some other parts and play the modification game!

mfewtrail · March 01, 2009, 06:36:51 PM

This should give you a good idea of the stock x-over size.

At the price you paid, it sounds like you didn't go with a good grade of steel...so your custom x-over probably isn't going to last real long. As small as the x-over is, it's not real expensive to go with 409 or 304 SS.

TGed · March 01, 2009, 07:40:56 PM

I am using header bends made for V8's . They are 14 or 16 gauge steel, I forget which. People use 18g all the time for home builds without issues. I figured with added heat I should go thicker.

Thanks for the pics!

kuntzie · March 12, 2009, 12:14:53 PM

heres mine...

Prospeeder · March 12, 2009, 02:21:09 PM

doesnt that stuff need to flex?

kuntzie · March 12, 2009, 05:20:57 PM

no it will be fine, there is a flex in the exhaust but its not needed on the x-over, its not like its one solid piece

TGed · March 12, 2009, 08:42:37 PM

specs

kuntzie · March 12, 2009, 10:55:58 PM

2.25" ID stainless, the manifolds are a thicker ga. stainless, the flanges are 3400 flanges incase i ever use these on a 3400.

the wastegate is 60mm or ~ 3"

notcheap but they will last forever

TGed · March 13, 2009, 07:39:52 AM

Have you ran it yet with the 2.25" ? Hows the spool up time?

kuntzie · March 13, 2009, 08:32:00 AM

you have seen my turbo right? it spools around 3000rpm