INTRODUCTION:
I want to create a “poor-man’*” HV insert for my 1998 LeSabre Series II L36…
http://www.zzperformance.com/grand_p...=214&catid=113

…because I think $200 for a modification I might be able to do for $40 is crazy. (The $40 is for a junker UIM I picked up from Ed Morad)

On this site (under Tech Info) you can find a tech report for the HV insert:
http://www.easyperformance.com/

I really would have liked if easyperformance had tested the HV insert without all the other mods on the test car, as I suspect the ER rockers synergized greatly. When I get around to my on-car testing, the only other performance mods I will likely have at that time will be two other low-cost items: 180° drilled thermostat (about $30 including coolant), and a home-ported LIM (about $40, also using a junker from Ed Morad):
http://www.bonnevilleclub.com/forum/...hlight=l36+lim

(ER rockers and a Powerlog v2 are on the list for this car, but not before the UIM/LIM work is done and tested).


OBJECTIVES:
We know the stock L36 has its torque peak at 4000 rpm, though looking at the stock dyno, it’* pretty flat on torque starting below 3000 rpm:
http://www.bonnevilleclub.com/forum/...ock+l36+torque

I would like to increase torque (of course), but also shift the peak torque up to somewhere around 4200 to 4300 rpm. The reason for this is that I feel this engine “drops off” at the tops of the gears, even with the stock shift points of 5700 rpm (1-2) and 5400 rpm (2-3).

I’d also like, as with the LIM porting, to do something that any stock, normally aspirated L36 owner could do on a tight budget.


CALCULATIONS:
Doing some calculations on this site with a 231 cubic inch v6:
http://www.wallaceracing.com/runnertorquecalc.php

I come up with:
A peak tq rpm of 3300 results in an optimum 25.45 in intake length, 1.44 sqin port
A peak tq rpm of 3900 results in an optimum 21.54 in intake length, 1.71 sqin port
A peak tq rpm of 4500 results in an optimum 18.67 in intake length, 1.96 sqin port

I measure the stock, "ugly" L36 LIM-to-head port at about 1.4 sqin, and I estimate the stock overall runner length (from intake valve seat to top of UIM plastic runner) at 12 to 13 inches. Assuming second order pressure wave (i.e., actual runner length half of optimum), this puts the stock LIM port optimized for ~3200 rpm and the overall runner length optimized for ~3800 rpm. This matches the stock dyno quite well.

So, what if I ported the LIM ports to about 1.7 sqin (optimized for about 4000 rpm), and shortened the plastic UIM runners by about 3 inches (total intake runner length then 9 to 10 inches, optimized for second order pressure wave at about 4400 rpm)? I would expect the stock torque curve to shift “rightward” by about 200 to 300 rpm…and hopefully “upward” as well.

(My understanding is that the HV insert runners are considerably shorter than what I'm talking about doing. While that surely shifts the torque peak even higher, it likely causes low-end losses that I don’t want, so I’m being less “aggressive” than the actual high-ticket item. Besides, if you shift the torque peak too high, you'll be forced to increase shift points, and then this wouldn't be cheap anymore 'cuase you'd need a tuner or a tuned PCM)


TESTING:
I’m too cheap to run dynos for you people, and as willwren predicted, the GTech sucked so bad it nearly pulled me out of my seat. So my plan is to optimize the VE table using a DHP PowrTuner (supposed to arrive this week), comparing “before and after” VE tables to see if I got any VE changes, and in what rpm range(*). If anyone else has any ideas for low-to-no-cost methods for quantifying these mods, I’m all ears.


OTHER CONSIDERATIONS:
Based on my quicky calculations, the UIM plenum volume on the Series 2 L36 is already massively oversized at over 150% compared with displacement—even correcting for the volume displaced by the plastic runner insert as-is—so the slight increase in plenum volume I’ll experience when cutting away part of the plastic runners shouldn’t require any correction.

I do not think I’ll need any intake mods to see results with the modified UIM; however, I do have a gutted airbox with K&N standing by, just in case.


Process (with pictures) will be documented starting with my next post, as this one’* getting too long…

Play around with it if you like, but you're going to lose noticable bottom end.

There should be another idea coming about around mid-summer that won't lose the bottom, and still gain on top.

That'* why I'm doing it on a "spare" UIM, so I can pitch if I don't like it. Also, I am wary because I've seen many posts talking about doing it, but none where anyone actually did it and reported on it.

I mentioned a "synergy" between ER rockers and the HV insert; I suspect that the HV insert loses low-end that the ER rockers regain. That'* why I would have liked to have seen a report on the HV insert alone. That'* also why, as I understand it, the HV inserts have gotten longer and longer from v1 to v2 to v3.

You mean the one the variable-length runners that were going to come out last winter :P ?:
http://www.bonnevilleclub.com/forum/...riable+runners
http://www.bonnevilleclub.com/forum/...riable+runners

I'm certainly interested in seeing that...but will it be cheap and easy-to-do?

I rethought the whole thing when the potential cost and complication went too high. I've found a new way of doing it that is simpler, more reliable, and cheaper.

I'm targeting around $150 per unit assuming you already have a core. $200 would be the cap.

Two test cars are already identified. I'm building the mockup, then the first test unit. One test car owner is then going to copy me to prove the feasability.

Here'* the stock UIM runner insert, perched atop my ported LIM:


You'll notice that each runner is a full tube with a rhomboidal cross-section for about 2/3 of its length, then becomes a "half-tube" for the upper 1/3. The other "half" of the tube in the curved section is formed by ridges inside the UIM itself.

This curved section averages 2.5 inches in length--just about exactly what I want to remove--so I cut the runners straight off with a fine-toothed hacksaw right where the "half-pipe" starts (yes, I should be wearing leather gloves):



I then smoothed the cutoff with a Mouse sander and fine sandpaper:



I marked each one as to which cylinder it came from...I will switch from tape to a paint marker or white-out (once I find some).

Here is the cut off "horn" fitted into the UIM:


Notice that the horn has a ridge all around the bottom that "sandwiches" between the UIM and the UIM gasket/LIM opening. Also notice on the cylinder 3 space of the UIM (at the left edge of the picture) that there is a horizontal "lip" or "ridge" that the top of the cut off horn abuts. Also, there are "wings" on either side that hold the runner in place. It surprised me how snugly that little beast fits in there.

Here'* all 6 of those bad boys cut off, and what'* left of the insert:



Not counting the undocumented pre-cleaning of the UIM and runner insert, I'm about 30 minutes in at this point (15 minutes if I wasn't taking pictures). More to come!

very nice to see what is being done for the L36 i like to know if the insert of a doorman intake and the stock one are the same thank you

Yeah, they're the same. The dorman is only different around the EGR passage... a little more material, so it takes longer for the composite to melt...

Looking forward to seeing the results.
Any plans on smothing out the transition from the UIM into the runner?

Final results are probably 4 to 6 weeks off...

I am thinking about that, and will begin to address that in my next batch of pics...

Here'* the six cut off pieces nestled all snug in their UIM:


And tucked in with a cozy gasket:


Here I've set the UIM atop the LIM, and clamped it down with some soft-jaw woodworking clamps to simulate bolting the UIM down:


Looking into the throttle body:


Although the cutoff pieces can shift around a little bit, they seem to be held quite securely in their places by the UIM and gasket, considering I tried with some force to pry them loose with a long screwdriver and couldn't:


Surprisingly, I don't think I will need to "glue" these things into place...however, if I do, I am undecided whether to use RTV or epoxy...any suggestions?

I am not happy with the way the openings face. I will probably wind up cutting them off at about a 45 degree angle in a miter box (as represented by the red line added to this picture), in order to both make the intake port larger and let them draw from the incoming air stream better: