seems like I remember (late last year) someone posting about cutting open a mini-ram to modify it.
does anyone have info on this?
I tried a search, but came up empty.

reason I'm asking:
have came to the conclusion that my AFR195 heads are too small for the 406. ordered some AFR210's. I'll have to do some weld build up and porting to match the bigger intake port. so while I'm doing that I might be interested in those mod's also.(wish I had read that post in more detail now)
anybody?
thanks,
RJ

 

Hmm, Don't recall hearing anything about tearing one open. However I did have mine welded/ported for the 1206 along with a little more work behind the throttle body and some unshrouding at the injectors.

Did you ever get your horsepower up? As I recall your trap speed was kinda low.

KM

 

maybe 8388 would know

 

88-406,
thats what I have to do to these heads (1206 gasket). did you just radius the injector openings?
you've got a good memory! last time I took it to the track was in oct/nov. it was running super lean above 4500rpm and did a 13.5@103mph (short shifting except for 4th gear) but it wasn't pulling on top at all. right now the A/F is pretty decent (dyno'd @ about 350rwhp from 4800 to 6000rpm, pretty flat though) and I'm sure it would do 12's, guess I should take it to muncie dragway and see what it does before I change heads, just for research :D

on different note, I have noticed the passenger side is running richer than the other side (except for cyl # 7 its rich too), seems that the ones closest to the fuel inlet are richest. so I'm thinking about adding another crossover tube near the front of the fuel rail, maybe that will help it? any idea's on what type of line and fittings (compression fittings?) to use?
RJ

 

ol RJ,
You do have a good memory. I am the guy who posted the info last year (Aug '01).

I have flowed, cut open, ported, smoothed, welded, drilled, and tapped the MRII. And then I did more flow readings and then more work. These intakes have a considerable amount of core shift and flows vary from port to port in excess of 15%. After all was said and done, I machined off the logos, beadblasted, and painted the intake, so the average guy would be unable to tell the mods. There is a picture of the intake (probably not too clear) on the C-4 forced induction forum under pics of turbo/sc applications. The heads out flow (by a sizeable amount) my AFR210CP with additional portwork. The fuel system was also modified considerably (-8AN feed, -6AN return, psi guage directly on the rail, larger crosover tube, ect). I spent a bit of time making sure this would not be the limiting factor on my slightly modded 408.

Best of Luck,
Aaron

 

ah, I thought someone had done it.
thanks for posting AKS, look's good. I can't tell its been worked over that much from the pic. I suppose your "slightly" mod'd motor needs all the fuel it can get :)
using the AN fittings would be a good upgrade from the supplied ones.
since I don't have access to a flow bench I guess some old fashioned porting will have to do. I have access to all kinds of grinders to do the work. probably just try to equal up the port size's and smooth everything inside the plenum area.
I'd like to put another connecting line across the fuel rails, seems like most FI units connect across the front and back of the fuel rails. not sure it will help but it shouldn't hurt it any either.
RJ

 

AKS, do you have flow numbers for the miniram? Just curious. I flowed a friends miniram with and without heads a while ago, and at .500 lift the heads flowed 248.6 cfm alone, with the miniram installed, it flowed 243.9 at the same lift.

I thought that the intake had to flow 15% more than the head in order to not become a restriction?

Just wondering if you flowed the intake by itself?

I tried, but the operator had no way of attaching the intake to the bench by itself.

 

I get asked a lot about flow numbers on various intakes. I have had access to a flowbench and have been doing this for quite some time. Here goes (peak numbers without head attached; 28" Hg):

TPI, stock base, stock runners, 48MM - 185 cfm
TPI, Accel base, large tubes, lots of porting, 52MM - 212 cfm
TPI, Accel base (cheater), large tubes, lots of porting, 52MM - 226 cfm

SR with unported Edelbrock base, 52MM - 224 cfm
SR with unported Accel base, 52MM - 233 cfm
SR with heavily massaged E base, mild port runners, 58MM - 256 cfm
SR with heavily massaged A base, mild port runners, 58MM - 259 cfm
SR with heavily massaged A base, massive work throughout - 278 cfm

stock MRII with 1204 (AFR 195) ports, 58MM - 265 cfm
stock MRII with 1206 (AFR 220) ports, 58MM - 281 cfm
MRII clean-up, 1206 ports, 58MM - 292 cfm
MRII cut, weld, port, ect, 58MM - 321 cfm
MRII (same as above with mono blade) - 322 cfm

My heads flowed 308 cfm @ 0.550" lift, so I felt I had gone far enough with the intake. Yes, you are correct that a good ROT for NA applications is 15% more flow from the intake than the heads. Very few FI intakes flow to that level, but the better ones work well with the factory type D-ports.

Lessons:
- Cheater intakes (connected cylinders) work well on very mild combos. Higher flows yield lean cylinders in real world apps.
- Flows above 230 seem to benefit from a 58MM TB.
- The monoblade (MB) seemed to show no appreciable difference at the 320 cfm level. I would suspect that it would show gains at higher levels.

My new heads (18°, 2.18" intake, 1.68" exhaust) flow in the 380 cfm range. Imagine the intake flow required to support them. (Sheetmetal w/ MB)

Good Luck,
Aaron

 

Aaron....super info. Great job!!!

380cfm heads!!! you're scaring me now...LOL!!!

thx

 

I agree, great info Aaron!

 

oop's, double post


[Modified by ol,RJ, 2:41 AM 4/26/2002]