High Compression L36 bottom + L67 SC (Corey's Engine Build)

well i got my motor and trans today i will upload pics soon as Dave sends them too me, let me tell you pulling engine and tranny sucks balls doing it thru the top. after our 7 hours of hard work and pain, we finally got it out, using just hand tools, and our brains. we pulled my L36 and 4T65e tranny, were going to do the HD tranny upgrade. some day. not until end of june or july tho., now its time for engine tear down, and prep for paint. yay more work. F**K. well she isnt done yet. but she will be in a few weeks of building and tunning and work and shit

Corey, I'm just rereading a few of your posts. Are you getting an L36 N/A block and putting the L67 S/C and associated parts on top of it?

yea, the L36 block is the same as the L67, but the L36 has higher compression . so you build more HP with lower boost. so what were doing is , we got a L36 block and are going to to put L67 heads,L67 LIM, M90 and a L67 throttle body on it. its like a high compression L67 pretty much. if you have any more questions Derek please feel free to ask, and i will help you understand the best that i can

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so you build more HP with lower boost.

Hold on a minute. Putting the L67 top end on the L36 block will give you higher compression, but not necessarily more power. What's going to happen is, the engine will build boost a lot more easily, and knock like a mo-fo before you can really get much power out of it. That's why the ZZP L36 M90 kit uses a 4"+ SC pulley. You may be getting lots of boost, but you won't be flowing as much with a pulley this big.

The reason you'll build boost so fast with the high compression is because it works as a restriction in FI applications. That's why you almost never see a supercharged engine combined with high compression heads - it's almost pointless because it's knock-city on pump gas. And the power gains are minimal because you aren't flowing as much air. It's similar to using a very small pulley w/IC on a normal L67, but with no cam or exhaust mods to move the air out. Lots of torque, but no real power.

What you really want is the 8.5:1 compression the L67 has, or even better... reduce the compression to 7:1 or so. This will let you cram LOTS of air fuel into the engine by boosting the hell out of it. Now you can burn a hell of a lot more air/fuel, and that's where the power is. I would rather boost 6 lb using 7:1 than 15 lb at 10:1 any day.

Sorry to rain on your parade, but I wouldn't do it if your plan is to have a really fast RIv. You may get into the high 13s, but no better, imo

AA wrote:

Quote :

so you build more HP with lower boost.

Hold on a minute. Putting the L67 top end on the L36 block will give you higher compression, but not necessarily more power. What's going to happen is, the engine will build boost a lot more easily, and knock like a mo-fo before you can really get much power out of it. That's why the ZZP L36 M90 kit uses a 4"+ SC pulley. You may be getting lots of boost, but you won't be flowing as much with a pulley this big.

The reason you'll build boost so fast with the high compression is because it works as a restriction in FI applications. That's why you almost never see a supercharged engine combined with high compression heads - it's almost pointless because it's knock-city on pump gas. And the power gains are minimal because you aren't flowing as much air. It's similar to using a very small pulley w/IC on a normal L67, but with no cam or exhaust mods to move the air out. Lots of torque, but no real power.

What you really want is the 8.5:1 compression the L67 has, or even better... reduce the compression to 7:1 or so. This will let you cram LOTS of air fuel into the engine by boosting the hell out of it. Now you can burn a hell of a lot more air/fuel, and that's where the power is. I would rather boost 6 lb using 7:1 than 15 lb at 10:1 any day.

Sorry to rain on your parade, but I wouldn't do it if your plan is to have a really fast RIv. You may get into the high 13s, but no better, imo

Aaron dont worry i have the best 3800 guy on the east coast and yes travis can tell you the same thing. and the riv will be fast, because im doing the same thing he did to his car(98 daytona GTP) he can run low to mid 12s all day long any day of the year

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he can run low to mid 12s all day long any day of the year

He could run 11s if he ran lower compression.

I hope you'll be running E85, or race gas, because otherwise you'll be knocking all the way down the track.

And I don't care who the guy is, he's not the best if he says to run high compression and FI together. It's basic engine knowledge that you will always make more power with less cylinder compression when using a supercharger.
You use boost to make up for the lack of cylinder compression.

AA wrote:

Quote :

he can run low to mid 12s all day long any day of the year

He could run 11s if he ran lower compression.

I hope you'll be running E85, or race gas, because otherwise you'll be knocking all the way down the track.

And I don't care who the guy is, he's not the best if he says to run high compression and FI together. It's basic engine knowledge that you will always make more power with less cylinder compression when using a supercharger.
You use boost to make up for the lack of cylinder compression.

i will be running 97 every day and 105 for the track. oooo i should tell you he runs stock heads. and we have the best tuner on the market so were ok.

I would run as far away from those guys as possible. Adding an M90 to an L36 block is fine if you already have an L36 in the car, but having the freedom to build an engine from the ground up, and taking that route is just dumb. Using an L67 bottom would let you run a smaller pulley, have less boost, and make more power... on 92 octane.

You are building a bomb, not a performance engine.

we know what were doing, dont worry there is tons of parts im not telling you guys about

I am sorry aaron but I am going to have to side with corey. Many guys on clubgp have done this successfully. If corey can make sure he doesn't get KR he will be better off. A stock top swapped grand prix GT will be faster then a stock GTP. Many guys after seriously modding there cars have upped the compression using a L36 bottom end. Corey will have a tougher time dropping pulley sizes and fighting KR but I wouldn't call it a bomb.

plus hey i have 3 of the best 3800 guys near me,dave pettinelli oldsman, and bill boost. im sure they could help me out if i had any problems :wink wink:

There's been a lot of reference to ClubGP lately regarding what is acceptable to do. This is by far the worst advice I've seen to date.

Again, I'm not saying it's a bad idea to put an M90 on a N/A motor - if that's all you have to begin with. It's a no-brainer that it will have more power than before, and because you are adding a few other mods, it may be faster than a stock GTP. Big deal. A modded L67 will be faster with the same amount invested.

What we have in Corey's case is a motor out of the car, with complete freedom to build the engine the best way, but whoever is guiding Corey is heading in the wrong direction. There is a good reason that virtually all blown/turbo cars use a comp ratio of around 8.0:1-8.5:1 (it's not to cheat you out of power potential). Simple fact is, you don't need high compression ratios when you have boost. In fact, it will hurt you because you aren't flowing as much air.

Read this article from TorqueCars.com: http://www.torquecars.com/tuning/adding-turbo.php

Notice the caption in upper left:

"Put a turbo on an engine with a 10:1 compression ratio and watch it go bang!"

This is why there are stroker kits, bigger heads, and thicker/domed pistons on the market to lower cylinder compression ratios. It's also why serious drag racers use compression ratios as low as 5:1.

Read Garret's tech pages on forced induction, it basically says the same.

Corey, I'm only making this argument because I'd rather see you succeed than fail. This M90/L36 recipe is comparable to recommending you decrease the diameter of your exhaust system in order to gain low-end torque. No, it's actually worse than that, because instead of chancing the possibility of extra knock, you will be playing with advanced pre-ignition. If you cross the threshold, you won't be cracking pistons, you'll be melting them.

Want more? Hear's a good thread from StangNet.com: http://forums.stangnet.com/showthread.php?t=739047

From TriniTuner.com: http://www.trinituner.com/shop/turbo.php

Isuzu performance: http://www.isuzuperformance.com/isupage/tech/turboing.html

Catastrophic results of high comp ratio + boost: http://www.lotuselancentral.com/forum/viewtopic.php?t=5249

Corey, I was asking because of the high compression ratio. It is well known that for forced induction applications you want low compression, or else you'll need to run extremely high octane fuel ALL THE TIME. Where are you going to get 97 octane for regular use? Are you turning this into a race only car? Just make sure you've done all your homework about running a very high compression ration with forced induction, along with it's fuel requirements.

If you want to run 92 or 93 octane you'll have to lose a lot of timing.

It's entirely possible to do, one of the advantages is that you can make more power with less air, i.e. a stock pulley. Don't go with a smaller pulley, though, until you have cam, heads, etc or an IC to give that air somewhere to go.

Good luck! Hope you have a good tuner working with you. It's gonna be a bastard to dial in.

Aaron the reason i choose the L36 is availability in my area , there are tons of them.i think i made the right choice thats my opinion. and im sticking too it. we will see who is mid 12s this summer, it will be me. like i said i have one of the best guys on the east coast and he knows his stuff, ask travis the guys that tunes his car was his room mate. these guys know the 3800. you dont have to like my swap.but i do thats why im doing it. also if the L36 is such a bad swap, why are all the impala guys doing it and the GP GTs.

hears the album of the guy thats helping me do my car, doing a top swap

https://s8.photobucket.com/albums/a17/04detroitls/Swap/?start=0

hears some video of the guy thats helping me build my engine and do the swap he has a N/A with a top swap




thats daves engine

also hear and i quote from the intense web site

"Stock L67 compression ratio is 8.5:1, and we offer two additional compression ratios. We recommend using the 8.0:1 pistons for engines being converted over to more efficient superchargers or turbochargers, and the 9.5:1 pistons for engines that will retain their original M90 superchargers. If you're running a better blower than the M90 you will benefit from running lower compression and working the new blower a little harder. If you're sticking with an M90 supercharger, you will make more power by raising your compression ratio and decreasing the boost, putting the supercharger in a more efficient speed range. "
http://intense-racing.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=IR&Product_Code=PKC-xxx&Category_Code=PBF

im not trying to be an A-hole im just saying we have done tons of these with no problem.

Quote :

There's been a lot of reference to ClubGP lately regarding what is acceptable to do. This is by far the worst advice I've seen to date.

ClubGP may not be the best forum on the net but when it comes to 3800 performance you have many Knowledgeable people and information on there for 3800. Yes Clubgp made posts saying the Intense GEN 3 rockers could be bad. Even though yours haven't failed doesn't mean the problem is not there. Granted ClubGP is Pro ZZP and against Intense racing in almost every way.
If people want to mod their 3800 powered cars Clubgp can be a great Resource for our cars.

I Really don't lke the ClubGP is bad sentiment . I have seen it on other forums and because of a few people who disagree with ClubGP and the younger members follow along they are denied great resource for info.



Sorry corey this is your show. I am done stealing coreys spotlight.

back on topic.

its ok, i was just saying. im not part of club GP, im more of 3800pro kinda guy myself. im not looking to argue about my swap in anyway,shape or form. this is a car forum not high school its not meant to be argued on.

I hope your guy is right then. Maybe he's that good and this will all work out with a happy ending. I really hope you can prove me wrong, seriously. I actually like being wrong because that's when I learn the most.

I don't think ClubGP is a bad resource, my only issue is when someone wants to do something, and they don't know why, they just say "someone at ClubGP did it", or "so-and-so is the best in the world when it comes to 3800 engines...", and that's supposed to be good enough. And that goes for any board, forum, or person out there - it's not enough for me and others who want to know more than "it goes fast" or "it just works". Some of us more inquisitive folks are interested in the theory and execution behind it, the "why" & "how".

And while it's great to have resources like ClubGP, I think it's better that we actually have an understanding of what's happening under our hoods, even when someone else is doing the work for us. It's clear to me that this (Corey's) engine build is an exercise in faith, a "because I saw someone else do it" thing. If someone could give a single good reason why mixing boost and a high compression ratio is a good idea, I might respect the plan. But instead, we're just supposed to believe it's an awesome build because someone else says so, or because there are "secret elements" of the plan that have yet to be unveiled (I hope one of these is a big IC).

Quote :

this is a car forum not high school its not meant to be argued on.

When the argument is about which 3800 block to mate up with what supercharger, we can call it a discussion. This type of debate is core of what this board should be about. We research these cars with every post we make, in hopes of learning from our experiences. Sometimes we may not agree, but that does not make it "high school". There is no drama here. This forum is absolutely meant for engine tech discussion, even if it gets heated at times.

Quote :

Yes Clubgp made posts saying the Intense GEN 3 rockers could be bad. Even though yours haven't failed doesn't mean the problem is not there.

Only a few were not phased by that fateful ClubGP post about the INTENSE Gen III rockers (which to me looked suspiciously like an altered crime scene from the photos). I'll admit, I popped a valve cover immediately to check mine. Everything looked great, then I remembered that Harlan Sharp invented roller rockers. I even had INTENSE check them to be sure, but it was determined there was no problem. I admit, I really was concerned at first, but then I decided to think instead of follow the propaganda.

Everyone got scared and yanked these products from their engines. Some of us used our head and said, "this doesn't make sense!", and kept them in. I know of 2 others that still run them, but I have never heard of a Gen III rocker actually failing, or an engine failing because of metal shavings in the oil. It's been about 3 years now, 85k miles for me. I admit there is some possibility I'm just lucky, but it doesn't feel that way, because the whole scandal always felt shifty to me.

Back to Corey's build: I'm glad you are doing this. It's different. We'll see what happens. Sorry if I came off as too negative, but I felt it was my duty to let you (any Riv owner) know of stuff like this. At least read into basic forced induction theory. Educate yourself so that you have a good idea of what's going on.

Okay, sounds like Corey has done his homework, let's let this go.

I agree it can be done, just hadn't seen mention of it and wanted to make sure you were aware what you were getting into.

deekster_caddy wrote:

Okay, sounds like Corey has done his homework, let's let this go.

I agree it can be done, just hadn't seen mention of it and wanted to make sure you were aware what you were getting into.

home work ? , i have been researching this for about 5 months. i have more then just home work , i have talked with numerous people who have done this swap, viewed there work,and rode in theres. sorry if i seamed like an A-hole before

Corey has been keeping me aware of your guys' concerns, so I figured I'd log in to help clarify where he's getting the advice from. It's understandable that guys like Aaron, above, would scrutinize a build that someone new is doing, so I have nothing but admiration for those comments.

I'm the guy in that photobucket gallery of the black/blue engine conversion, wearing the black t-shirt with the hat-hair. That car went from running 15.3's N/A the week before, to 13.8's at Intense Drag Day the following month, nearly winning Most Improved since previous Drag Day event.
"2. Kevin Robbins (MI) � �04 Impala LS � 15.310 > 13.832 = 1.478 (N/A at IDD VII)"
He's now running a Stage 1x cam build and headers with that motor, and had dropped almost a half second thus far. He just bought a larger cam (similar size to Stage 3), a set of Stage 2 heads I had laying around, and an intercooler... with some tranny work and plenty of tuning time, his goal is to work down to 11.9's by fall. Very possible, since a MN member just ran 11.96 @ 114 last fall with a build identical to mine, plus intercooler and slicks/race prep.

If I hadn't built multiple other successful cars with this core setup (M90 on 9.4:1), let me be the 1st to say I would NEVER make a guy like Corey (starting off modding, on a budget, etc.) be the guinea pig. I've hand-made many custom parts for various Series 2 applications, and majority of them are tested on my own car before getting handed off to the recipient (mainly because I generate the idea based on something my car required).

In no way do I know "everything"... as a matter of fact, I take pride in knowing that there's tons out there I don't know, BUT I realize the knowledge exists and can be obtained through others to fill in blanks. My ability to make personal contacts and dig through information to fill those blanks is what tends to provide the confidence for me & the people I help. I've made more close friends by helping them with 3800 builds in my years going to college and working in the Midwest, than any other means.

L36-block usage is much more common than it seems to be observed in this post. Your assumption about compression vs. boost is entirely right, but there's some different flavors within the apples & oranges we're discussing here. "High" compression when it comes to car engines is something in the 10-11+:1 range, which most performance N/A cars start off with.

Our levels of 8.5 and 9.4:1 are both "low" in the grand scheme of the OEM c/r's, but I will personally attest to the increased touchy-ness of 9.4:1, causing some extra caution when keeping after an aggressively boosted setup for the past 3yrs. I will also attest to the advantage an M90 setup has by running over an L36 block, as I was able to make strong power numbers with very limited mods before I even knew what potential we had.

Since doing my own motor swap from 8.5:1 to 9.4:1, with half a club on-hand to observe the work back in MN in '05, I've not only been my own personal test mule, but done plenty of helping with others in Detroit and Minneapolis who followed in this path. With so many folks on-hand with regular interaction, there's many things we gladly discuss to no end, believe me.


(I didn't go past half throttle for almost 2 months/5k after this, with a very conservative pulley for the setup, just because I had alot of KR concerns before I finally decided to see how it'd dial in. (Didn't knock with 3.3 pulley & did two 13.3's @ 105 on a brief trip to Milan dragway back then... before headers, Gen5 blower, 75mm TB, injector upgrade, and being able to run a 3.0 on the street & 2.7 on 100 unleaded)

Hope to continue to constructive conversation. I wouldn't want to see one of my fellow members steering in the wrong direction either, so feel free to inquire further if necessary.

BTW - here are Corey's engine-tranny-harness-pcm pics I snapped Friday...









- Dave

palermocorey90 wrote:

also hear and i quote from the intense web site

"Stock L67 compression ratio is 8.5:1, and we offer two additional compression ratios. We recommend using the 8.0:1 pistons for engines being converted over to more efficient superchargers or turbochargers, and the 9.5:1 pistons for engines that will retain their original M90 superchargers. If you're running a better blower than the M90 you will benefit from running lower compression and working the new blower a little harder. If you're sticking with an M90 supercharger, you will make more power by raising your compression ratio and decreasing the boost, putting the supercharger in a more efficient speed range. "
http://intense-racing.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=IR&Product_Code=PKC-xxx&Category_Code=PBF

.

I read this on the INTENSE site a while ago and was planning to go with the higher compression when it came time for a rebuild. I plan on keeping the Gen III M90 and not upgrading the SC.
So what is the boost limit on the Gen III when running that higher compression (9.5)?

Dave, welcome to the board, and thanks for the explanation. Based on what you've said, I don't doubt you can do what you claim. You seem knowledgeable of the subject. And I mistakenly was thinking the L36 had a 10:1 comp ratio, so I guess I overreacted a bit. Thanks for clearing that up.

I would personally not take on such a project, but if you've done it over and over with good results, I say go for it. We can't just use the same old formula forever, right? This will be a first for the Riviera, I'm pretty sure of it.

I still have a couple more questions, Dave. By using an L36 block, which requires an IC to run the smaller SC pulleys, wouldn't it cost less in the end to just use an L67 block and no IC? My car ran about 15.5 stock, and now runs 13.9 without IC or cam (under $3k invested). Similar results to the '04 Impala you mentioned.

Also, when using the L36, do you run with the stock pistons?

Hey Dave, welcome aboard! Nice to see ya over here. (Dave is well-known among the MNClubGP guys)

What's up 98Riv. Got some projects going in NY now too, as you can see with the Riv one that's on deck now.

Bunch of good questions, I'll do bullets.

- no boost limit, even Zooomer did this for his 10.8sec XPZ cam car with a Gen3 M90 with the smallest pulley his shop makes

- the L36 block is definitely a bigger fan of knock-reducing mods like an I/c, but cost in the end isn't quite identical. My car also went into the 13's without going past a 3.4/pcm/intake/downpipe/catback (13.7 @ 99 w/ 2.07 was my best like that in '04). Your chassis' are definitely heftier, so I'm sure it took the help of rockers, headers, and such to move that thing good like that.

- The Impala was just starting off with the L67 top, and he went to the track sooner than I would've liked, but some people get over-anxious & make you pull your hair out before you can say NO. At the time, he still had a small N/A cam in there, you'll notice the yellow LS6 springs on the heads I installed, which may or may not have helped (I'd like to think the extra overlap with only 112 LSA was relieving some of the pressure, since he started off with more pulley than I wanted him to... a 3.4 or 3.5).

- costing less to IC rather than 9.4:1? That's a somewhat odd way to look at it. I can explain it by saying that doing a block swap is not a light undertaking, and an I/C install is less work to complete. The cost is slightly more, due to the pretty parts you have to buy, compared to just needing an L36 engine that can be had for as little as $100 plus gaskets/fluids. Gains from each, however, are different. The I/C will produce a better gain than just bumping compression that point, but that's not why this decision was made. Both of these items should be considered a positive upgrade for an M90 build, but we weren't doing something to add onto a build, it was to get it started & only one of those items has a rotating assembly, but the I/C can be bought later at his leisure, giving him the advantage of adding that mod on top of a more aggressive motor already.

- my pistons are stock (new block shown in pic I got with 1,740mi on it from a LaCrosse in MN). I ran an '01 Park Ave L36 that was swapped in during that session shown in the garage meet 3yrs ago, and removed for this new one. I have another engine I'm building with forged 8.0 Diamonds, which are with an Intense race block from years back. That's going under the larger MP112 blower & I/C setup I'm putting in a RWD project that may turn out to be drag-only, but I hope not.

Here's the car I just pulled that motor from, for a demod (found him a stock '04 L32 with 6k that he's driving with now)...



New motor that went in...


He didn't exactly get "crap", but I definitely got a nice core to build a monster build around, later this summer. I told him that I'll fly him out for the 1st track day. Until then, Corey gets the majority of my attention (except when a chick walks by).

- Dave