99 SL1 SOHC to DOHC swap

mb17180116 · 09-20-2006, 09:23 PM

Just wondering, if i wanted to swap out my SOHC engine on my manual 99 SL1, for a DOHC engine from the same year....would it be a simple take one out and put the other in kind of thing, or would it require some kind of modifications. Also, what other parts would i need to switch over?

andy_95sl2 · 09-20-2006, 10:01 PM

you need the DOHC motor, DOHC gauge cluster, DOHC computer (and dohc transmission if you have an automatic) DOHC engine harness (can probably use your current one) and thats pretty much it.

madpogue · 09-21-2006, 12:30 PM

You can use your existing MP2 tranny, but it's geared more for economy than its DOHC counterpart, the MP3. That combination will get you better fuel economy; 70 MPH will rev at about 2700-ish. If you also swap in the tranny (or replace the complete powertrain as a unit), you'll get something closer to the full DOHC "experience" performance-wise. 70 MPH revs at just about 3000 RPM.

Monkius · 09-21-2006, 12:42 PM

Quote:

Originally Posted by madpogue

70 MPH revs at just about 3000 RPM.

2800

I love my magical calculator.

madpogue · 09-21-2006, 12:45 PM

Quote:

Originally Posted by Monkius

2800

I love my magical calculator.

Well, then, either my speedo or my tach is off. Other DOHC 5-speeders, where are you, at 70?

RangerRover · 09-21-2006, 12:49 PM

about 3k... give or take.

Monkius · 09-21-2006, 12:57 PM

I haven't driven that fast constantly in a while, a lot of city driving... But I was at 2500rpm at 62 the other day. Factory speedos ARE off a little bit, though... That's why the cops don't bug you if you're not speeding by a lot.

Dr B · 09-21-2006, 02:02 PM

I was driving A 2001 GM car awhile back ( intrigued by )
65 mph @ 1700 rpm
could we get this on our cars ?

fetchitfido · 09-21-2006, 05:08 PM

Quote:

65 mph @ 1700 rpm, could we get this on our cars ?

It's called 5th gear for me. but I've got the SOHC with the default tranny for now.

Monkius · 09-21-2006, 07:57 PM

Quote:

Originally Posted by fetchitfido

Quote:

Originally Posted by Dr B

65 mph @ 1700 rpm, could we get this on our cars ?

It's called 5th gear for me. but I've got the SOHC with the default tranny for now.

Lol, the MP2's gearing isn't even that tall... 1700rpm in fifth on a SOHC equals 50mph. What were you driving, a Cadillac?

09-20-2006, 09:23 PM	#1
mb17180116 New Member Join Date: Aug 2006 Posts: 6	99 SL1 SOHC to DOHC swap Just wondering, if i wanted to swap out my SOHC engine on my manual 99 SL1, for a DOHC engine from the same year....would it be a simple take one out and put the other in kind of thing, or would it require some kind of modifications. Also, what other parts would i need to switch over?

09-20-2006, 10:01 PM	#2
andy_95sl2 Master Member Join Date: Jan 2006 Location: Grafenwoehr, Germany Posts: 3,207 andy_95sl2's Photos	Re: 99 SL1 SOHC to DOHC swap you need the DOHC motor, DOHC gauge cluster, DOHC computer (and dohc transmission if you have an automatic) DOHC engine harness (can probably use your current one) and thats pretty much it. ... 2004 Jeep Wrangler Rubicon -> daily & toy =) 2009 BMW 128i -> sold 2003 VW GTI 1.8T -> wrecked 1998 Saturn SL2 -> parted out 1995 Saturn SL2 -> sold 1995 Saturn SL2 -> sold

09-21-2006, 12:30 PM	#3
madpogue Super Member Join Date: Sep 2004 Location: Madison, WI USA Posts: 25,715 madpogue's Photos 1996 SW2	Re: 99 SL1 SOHC to DOHC swap You can use your existing MP2 tranny, but it's geared more for economy than its DOHC counterpart, the MP3. That combination will get you better fuel economy; 70 MPH will rev at about 2700-ish. If you also swap in the tranny (or replace the complete powertrain as a unit), you'll get something closer to the full DOHC "experience" performance-wise. 70 MPH revs at just about 3000 RPM.

09-21-2006, 12:49 PM	#6
RangerRover Senior Member Join Date: Dec 2005 Location: Creedmoor, NC Posts: 1,648 RangerRover's Photos 1999 SW2 1994 SL2	Re: 99 SL1 SOHC to DOHC swap about 3k... give or take. ... You can tell Linux is made by geeks.

09-21-2006, 12:57 PM	#7
Monkius Advanced Member Join Date: Nov 2005 Location: RAWR! Posts: 799 Monkius's Photos 1998 SW2	Re: 99 SL1 SOHC to DOHC swap I haven't driven that fast constantly in a while, a lot of city driving... But I was at 2500rpm at 62 the other day. Factory speedos ARE off a little bit, though... That's why the cops don't bug you if you're not speeding by a lot.

09-21-2006, 02:02 PM	#8
Dr B Senior Member Join Date: Mar 2005 Location: Alabama Posts: 1,498 1992 SL2 1993 SL2	Re: 99 SL1 SOHC to DOHC swap I was driving A 2001 GM car awhile back ( intrigued by ) 65 mph @ 1700 rpm could we get this on our cars ? ... Have A Great Day , it is YOUR choice !

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