L26 top swap on the SLE - 56Ks welcome

[radomirthegreat]

1337ssei called me at 1 am and asked if I wanted to swap to the L26 UIM. Well, yes! I packed up, left, and arrived at his house just past 2 am. I still haven't slept, but the new & improved SLE is awesome! I will upload a video by tomorrow, most likely. Here are some pictures of the tiny meet. Some may see I haven't yet finished cleaning up and polishing the UIM. That's because I planned to polish it and have it clear powder coated. However, this aluminum corrodes very quickly. I figured I woiuld get an early start on the polishing, but it looks like I'll just delay the powder coating and leave the polish job half-done. Ultimately, I'll take off this combo and put it into the 94 for what I have planned.

I used the PCM housing as a screw and nut retainer. Everything but the coolant elbows was very easy to do. We tried to leave the rear bracket on the whole time, but it is too hard to manage the engine that way. Odd alignment and a new coolant elbow springing a leak had us put on the same alternator three times! See if you can follow these pictures. I don't yet have the SLE tuned for the throttle body and 97 MAF sensor change. It appears fine, but it's going to PRJ Performance ASAP for a 92 octane tune. I'm doing this strange thing at my own discretion and have an engine code. P107 came up, but it was after a fallen off plug wire prevented the car from starting.



We noticed almost immediately that the L36 UIM had been leaking straight onto the LIM.
http://i106.photobucket.com/albums/m242 ... CF4019.jpg

This is not how you relieve the fuel system of pressure before removing fuel injectors:
http://i106.photobucket.com/albums/m242 ... CF4020.jpg

The stock fuel lines have a point where they love cracking. Do not remove them from the shown clips, and you shouldn't experience issues.
http://i106.photobucket.com/albums/m242 ... CF4021.jpg

It's not plastic, but Nylon 66. And it cracked. Granted, it was by the throttle body, and most likely due to improper torque specs.
http://i106.photobucket.com/albums/m242 ... CF4025.jpg










GM made a big mistake with the coolant elbow, because of which we had to redo the side accessory bracket. In the provided picture, 1337ssei is employing a technique not at all recommended to take out pieces of the broken elbow.
http://i106.photobucket.com/albums/m242 ... CF4034.jpg

And now, this is the installation of the ported LIM, L26 UIM, and L67 throttle body.

[GoldenBullet]

looks good, rad. hows the swap working out so far?

[00Beast]

Score for Radomir!!! X2, how's it working?

[radomirthegreat]

Thanks! It has tons of high end power. Whereas it would at first pull pretty nicely but then cut out at the high end, now the driver and passenger are pushed back into the seats all the way until the shift point. I've gained insane power!

This is totally without a tune, too. I started with a 99 L36 MAF sensor and throttle body, but now I'm using a 97 L67 MAF sensor and TB. I believe I'm running slightly lean, but this shouldn't at all be a problem for an NA application. I'll still go easy on the car until I can get it all tuned up. The video I have is of starting the car, and a driving video will be uploaded shortly after the tune. Maybe immediately after it.

[laxmangl]

Very Very Very cool, Keep it up.

[sandrock]

You didn't gain an insane amount of power. I have an L26 upper in my garage as we speak, and when compared to the L36 upper, the throttle body opening is actually smaller...it necks down substantially, and due to the casting, there really isn't much there to open it up. Based on that alone, I'd stay WITH the L36 upper unless I went turbocharged.

As far as your tune goes, the factory tune just won't do it. You NEED to get that thing tuned correctly. But, I shouldn't have to tell you this......

[willwren]

Time to ground ourselves in reality here before someone that doesn't know better may mistakenly believe this is a go-fast mod.

The L26 engine does not have any performance advantages over the L36 in any real sense. Perhaps the biggest improvement would be the SLIGHTLY larger intake valves (1.83" as opposed to 1.8"), but you didn't do that. Other than that, the stronger powdered metal rods (which you didn't do) and the aluminum upper, which you did based on Agrazela's encouragement for longevity, not performance (even though the APN and Dorman UIM still offer longevity).

I'm not seeing how this mod made an 'insane amount of power' or 'tons of high end power'. It's a slightly different design of UIM and a different material, and still has the issues Sandrock pointed out. Smaller neck and lack of a tune.

Now that we're back with our feet firmly planted in reality and on Terra Firma, Good work on getting the swap done and keeping things clean and organized.

[1337ssei]

We did do a ported lim and L67 tb at the same time. It definitely pulled a lot harder than before. How much of that was related to the UIM or l67 tb? I don't know. However, it looks a hell of a lot nicer than a black piece of plastic and for sure felt a ton sturdier. We did find a crack and warpage on the old nylon 66 UIM and that will never be a problem again.

[sandrock]

The ported lower is the whole reason there is more power after the swap. The L67 TB does little good when you consider the bottleneck that L26 upper has...it's just as big as the 92/93 throttle bodies after that is taken into consideration.

[1337ssei]

I would think just in terms of flow an oval would be bad. The L26 is a circle that slightly tapers but that would step up the velocity just before it enters the UIM I would think. Even if the l36 intake has a bigger overall opening the shape needs to be taken into consideration as well

[willwren]

There's alot of assumptions being made here. Ultimately, if there is a performance gain, it's minimal, and perhaps non-existent without the appropriate tune for the hardware changes.

It's by no means what it was claimed to be above. Again, well done on the work, cleanliness, and organization, but let's not make claims that may cause disappointment for someone in the future.

[1337ssei]

I'm not saying that just the UIM gave insane performance. All three mods as a whole however gave the car a much better feel even without a tune. It wasn't "insane" but the butt dyno tells me it pulls significantly harder and more evenly. I'm sure it will be even better when we get the correct MAF tables in the PCM. Also, thanks for the compliments guys.

[sandrock]

Yes, the execution looks great...and I like how that mani polished up

[Roadtech195]

Looks good Rad. Time to get some 1.8 rockers

[radomirthegreat]

Thanks for the compliments!

I never said the L26 UIM got me the gain. In fact, it could be that I got all that power from the LIM. I've been aware for a long time that a ported & polished LIM is one of the best mods to do to an L36. In no way am I interested in understating the importance and awesomeness of a P&P LIM. However, as apparently was guessed, I do credit some of the power to the L26 UIM, and I still stand by this claim.

The L36 UIM has an oval opening and just lets that go. On the other hand, the L26 UIM has a rounded opening that tapers down. This certainly helps increase volumetric efficiency, and earlier it was shown through graphs and words that VE is proven to increase with an L26 UIM swap. Agrazela predicted a 5-7% gain in horsepower, or about 10. It's probably not that high, and especially not with the tune. I'd say I can ideally get about 10 HP after a tune, but probably not. Not only that, but this rounded opening is much better fitted to the L67 TB than the L36's UIM opening can be. If you think you can go fast with roughly 5 more horsepower, then this is a go-fast mod. If you do not think that you could ever notice 5 more HP, then this is not a go-fast mod.

And yes, sandrock, you should never have to tell anyone to get a tune because of a change from a 99 to a 97 MAF and TB. It's common sense. I'm clearly not using said sense, and I encourage everyone reading this thread not to do as I have done. Let's make a list:
• Do not relieve fuel pressure by shooting fuel into your engine bay while catching some with a paper towel.
• Do not stick a wide flathead into any cavity that has a broken off gasket and then proceed to scrape.
• Do not run a car with a different throttle body and MAF sensor without a tune.

I recently got back from filling up with 93 octane gas. I was nearly on E with 87, and I'll use 92-93 oct gas from now on. Hopefully by Mon or Tue, I can go to PRJ and have the car tuned nearly to perfection. Real perfection will have to wait until summer.

[agrazela]

Thanks for the compliments! ...This certainly helps increase volumetric efficiency, and earlier it was shown through graphs and words that VE is proven to increase with an L26 UIM swap. Agrazela predicted a 5-7% gain in horsepower, or about 10.

With the L26 UIM on the L36, I demonstrated a 5% to 6% increase in WOT VE in the powerband, which I estimate is a 4 to 5 ft-lb increase in torque and a 5 to 6 hp increase. This is on top of the similar increases from the L67 TB. I still don't know why the L26 UIM increased VE, but it did.

I found these increases to be definitely noticeable, though not what I'd call "kick-in-the-arse" awesome.

[willwren]

The L36 ported LIM is probably good for 5-10hp by itself. This is what I'd call BARELY perceptible, or at the seat-of-the-pants-dyno threshold. The reason it feels like more is easily explained. I'm not aware of anyone characterizing the difference in performance from an oval opening to a round, but my simple mind might think the oval opening is designed to allow more direct flow to each bank of runners, front and rear.

Peak horsepower improvements don't represent by number an improvement in the powerband lower down. Did the curve straighten out? Does it peak earlier? There are still alot of questions, but it's important NOT to over-state the gain until you've put the car on the dyno.

With regards to the L26 upgrade, I personally doubt whether any gains were made at all until after a tune. The combined gain from all the work is probably only in the 10-15hp range after tuning. So let's not use words to describe the gain that may be interpreted as something they're not. For instance, the first pulley drop on an SSEi typically nets 25hp/40ft-lbs.

[agrazela]

All the cheap, "home-made" L36 mods together--PLIM, "fake" PEM, L67 TB modded to fit, L26 UIM modded to fit--increased WOT VE across the powerband by some 0.14 to 0.16 VE units more or less evenly across the board:



And yes, these mods do require tuning to get the full potential.

Based on correlating calculated VE from WOT scan data and dyno numbers collected from cars on various 3800 forums, I estimate that this equates to some 20 to 25 ft-lb torque at 4200rpm and some 15 to 20 hp at 5200 rpm increase all told. Not killer, but not bad for a small investment (assuming you have tools and tuning access) in some cheap, easily obtainable, easily modifiable stock parts.

[radomirthegreat]

The oval opening would be there to make the air past the corrugated intake tubing flow more easily to the F&R cylinders if the rest of the design supported it. As I am aware, the TB goes from oval to something narrower to oval again, and the L36 UIM takes that oval shape and then opens up to all the ridges of the cylinders. With that design, since we're only speculating, I assume cylinders 5, 6, 3, and 4 get the most air with 3 and 4 having increased turbulence.

[tripscarcare95]

You need to lay off the Red Bull!


Keep us posted I always enjoy reading your threads, Hows the car on gas after the tune?