Jump to content

L27 vs L67 questions


Guest TurboSedan

Recommended Posts

Guest TurboSedan

there is a '94 Pontiac Bonneville SSEi i am looking at and have a few questions.

 

first off, the supercharger coupler went out so the owner had it removed and L27 intake manifolds were installed so it's now naturally aspirated. the car is SLOW. i mean really REALLY slow. doesn't the Series I L67 have lower compression than the L27? so without boost that would account for part of the reason the car is so slow right? i believe the car is also still using the L67 computer (do these cars have a memcal?)...if so wouldn't that also make the car run wierd ie slow? hell for all i know the car might still have a 2-bar MAP (assuming they are not MAF cars....i have alot to learn about the 3800s....). i really like the car; it runs good and looks great besides a few minor things but it's slow as hell as it is right now. although, it's a perfect candidate for a Series II L67 swap that's for sure.

 

so what is the compression ratio difference between the Series I L67 and the L27?

 

any input appreciated, thanks.

Link to comment
Share on other sites

Well, from what I heard the SI L67 does have lower compression than the L27. Don't quote me, but I think the L27 has 9.0:1 and the L67 has 8.0:1. This was discussed before: http://www.w-body.com/forum/viewtopic.php?t=15681

 

I have a SI L67 (M62) Supercharger with the LIM and injectors attached packed away in my shed that I could sell you if you're interested. I was going to slap it on my Regal, but I've since decided to swap in a complete SII L67 drivetrain instead.

Link to comment
Share on other sites

Guest TurboSedan

wow, i just read that thread....good info! thanks for posting that link. it wouldn't be that hard at all to convert this '94 SSEi back to supercharged with stock parts but then again maybe Series II L67 would be the way to go. DiscoStudd, if i do end up with this car i will be PMing you!

 

and onto some more questions:

 

1) the L27 & Series I L67 cars are MAF right? so no MAP sensor (2-bar) is used on the Series I L67?

 

2) are the injectors different between the L27 and Series I L67?

 

3) is the EPROM code different between the Series I L67 and the L27? i would think it would have to be but i have alot to learn. also, do the Series I cars use a PCM or and ECM + memcal?

Link to comment
Share on other sites

there is a '94 Pontiac Bonneville SSEi i am looking at and have a few questions.

 

first off, the supercharger coupler went out so the owner had it removed and L27 intake manifolds were installed so it's now naturally aspirated. the car is SLOW. i mean really REALLY slow. doesn't the Series I L67 have lower compression than the L27? so without boost that would account for part of the reason the car is so slow right? i believe the car is also still using the L67 computer (do these cars have a memcal?)...if so wouldn't that also make the car run wierd ie slow? hell for all i know the car might still have a 2-bar MAP (assuming they are not MAF cars....i have alot to learn about the 3800s....). i really like the car; it runs good and looks great besides a few minor things but it's slow as hell as it is right now. although, it's a perfect candidate for a Series II L67 swap that's for sure.

 

so what is the compression ratio difference between the Series I L67 and the L27?

 

any input appreciated, thanks.

-The Compression ratio is the same from the L27 to the L67.

-The timing on the L67 has less advance than the L27 <- that's probably the main reason why it's slower.

-The L27's got a MAP sensor, but it's not used to fuel, It's still a MAF fuel controlled system.

 

Personally I'd just put a series 2 L67 engine in there. You already have the HD transmission and the 4T65-E will require a PCM change. (line pressure is electronically controlled in the 65-E)

Link to comment
Share on other sites

From what I remember, the PCM's are the same, just the memcals are different between the 2 motors. IIRC, both are MAF only with no MAP (I never saw a MAP sensor on either of the 2 L27's I've owned.)

 

I just thought of another site to check out:

http://www.gmtuners.com

 

This page describes the differences in 3800 PCM's (it's linked off of the above site) :

http://dtcc.cz28.com/eprom/3800PCM.htm

 

The guy running the site is a member over at L67swap.com and has done several L36 and L67 Fiero swaps. I was going to contact him regarding a custom memcal when I had planned on putting the M62 on my L27. Sounds to me like he really knows his shit...

Link to comment
Share on other sites

Guest TurboSedan

 

great info in that thread too, thanks :)

 

Sean, does the '94 SSEi have a 4T60-E or a 4T60-E HD? the '94 SSEi i'm looking at had the differential replaced last December according to some reciepts i have here from the seller...i highly doubt they used a diff from a supercharged car. is the differential stronger or is both the transmission itself and the diff stronger for the Series-I L67 equipt cars?

Link to comment
Share on other sites

Sean, does the '94 SSEi have a 4T60-E or a 4T60-E HD? the '94 SSEi i'm looking at had the differential replaced last December according to some reciepts i have here from the seller...i highly doubt they used a diff from a supercharged car. is the differential stronger or is both the transmission itself and the diff stronger for the Series-I L67 equipt cars?

4T60e-HD. I honestly don't know enough about the transmissions to tell you anything about the differential, but try asking Dr. Jay on BonnevilleClub. That guy knows his shit.

Link to comment
Share on other sites

http://www.seriesoneperformance.com/

 

Did a search and it looks like that stuff that was mentioned earlier on the Bonneville board(in another thread here) is now offered at this "store." My parents have a 1994 Regal w/ an L27 in it and it doesn't feel that "slow" to me. It ran a 16.7@84mph back in 2003 when I ran it, about 85-90* & humid out so it felt slower that day(one magazine test shows a 16.0 or 16.1 for a L27'd Regal).

Link to comment
Share on other sites

Sean, does the '94 SSEi have a 4T60-E or a 4T60-E HD? the '94 SSEi i'm looking at had the differential replaced last December according to some reciepts i have here from the seller...i highly doubt they used a diff from a supercharged car. is the differential stronger or is both the transmission itself and the diff stronger for the Series-I L67 equipt cars?

Yes it has a 4T60-E HD. Not too sure about the diff. My Regal has a 3.06:1 diff. not sure what the H bodies has with the L67. Couldn't be too much worse.

 

The diff might be slightly stronger. Personally I wouldn't worry too much about it.

 

From what I remember, the PCM's are the same, just the memcals are different between the 2 motors. IIRC, both are MAF only with no MAP (I never saw a MAP sensor on either of the 2 L27's I've owned.)

The series 1 L67's might have a MAP, but it isn't for fuel, just for a boost gauge. GM did this on the Turbo Trans Am. It has a 3bar MAP sensor and it's only purpose is to move a gauge.

 

 

Oh, BTW. in the link that Disco posted I said that 93-95 L27's had 9.0:1 compression. I have since learned that my chiltons manual is wrong, and that the compression stayed at 8.5:1.

Link to comment
Share on other sites

Wow, didn't think the comparison we did on BC would make its way to other forums. Hope it was helpful to those who read it.

 

To clear a few things up with reguards to the series I:

 

The compression ratio between the l27 and l67 is the same. Both carry 8.5:1.

 

The l67 has a map sensor, its on the engine towards the firewall. The map sensor drives the boost gauge. They are both mass air systems.

 

The bottom end differences are minimal but the l67 has floating pins while the l27 was press fit. Helpful but not necessary. There is some debate about the makeup of the rods, but I'm lead to believe they're both cast.

 

The -HD transmission got a few beefed up pieces but mainly just the final drive. The -HD transmission came with an FDR of 2.97 but the 60E was available with 3.06 and even 3.33.

 

The l27 has 21# injectors while the l67 has 30#.

 

Hope that clears a few things up.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...