jonlabree Posted November 15, 2012 Share Posted November 15, 2012 Does anyone know if the 90 and 91 Exhaust minifolds are the same or different?Jon.. Link to comment Share on other sites More sharing options...
dship Posted November 16, 2012 Share Posted November 16, 2012 I looked it up in the 1988-1993 Parts & Illustration Catalog for Riviera/Reatta:Left hand exhaust manifold part# 24501727 good for 1988-1992 LN3 & L27 3.8L enginesRight hand exhaust manifold part# 25537100 good for 1991-1992 L27 3.8L engine onlyRight hand exhaust manifold part# 25531722 good for 1988-1990 LN3 3.8L engine only Link to comment Share on other sites More sharing options...
2seater Posted November 16, 2012 Share Posted November 16, 2012 I seem to remember the front manifold went to a cast manifold on the later model to help with converter light off due to greater heat retention. Hopefully someone with a '91 can confirm.I just looked at those part numbers and the right manifold is the one on the rear? I would have thought that would be listed as the left, as in the engine positioned front to rear like in a rwd? In any case, the '91 rear manifold looks exactly the same as the LN3 except it has no provision for an EGR tube. I did see a reference to two different designs for the front, one with a seperate crossover and a second design with a crossover integrated with the front manifold. For reference purposes, bone stock, the individual ports flow 151-202 cfm @ 28"w.c (or approx. 1 psi of pressure). This is tested as assembled on the engine pulling a vacuum through the rear outlet with an O2 sensor installed. A ported and ceramic coated set I have flowed 196-249 cfm under the same test conditions. Removing that rear restriction really does help potential flow. Modified further as below helps even more. Link to comment Share on other sites More sharing options...
jonlabree Posted November 16, 2012 Author Share Posted November 16, 2012 Anyone have one that is pipe not cast for sale?Rear only.Jon.. Link to comment Share on other sites More sharing options...
dship Posted November 16, 2012 Share Posted November 16, 2012 Reading from the pages of the Parts & Illustration Catalog....Left hand is front, right hand is rear. Cast manifold was on 2nd design of the 1992 Riviera model L27 engine. Link to comment Share on other sites More sharing options...
2seater Posted November 16, 2012 Share Posted November 16, 2012 Now that you mention front/rear vs left/right, I realize I was imagining the engine rotated the wrong way. Now it makes perfect sense. Sheeesh. Link to comment Share on other sites More sharing options...
padgett Posted November 16, 2012 Share Posted November 16, 2012 I prefer front/rear or drivers/passenger side. In this country that is unambiguous. Most V engines I have known the odd cyl were on the driver's side but Chrysler is different. Link to comment Share on other sites More sharing options...
D-a-n-i-e-l Posted November 17, 2012 Share Posted November 17, 2012 2SEATER,You are runnign your turbo off one side. correct?How is it holding up? Link to comment Share on other sites More sharing options...
2seater Posted November 19, 2012 Share Posted November 19, 2012 Yes, it is still connected to the front manifold only, hence the reason for the odd modification to the rear manifold. Boost is a little lower than I would like at about 4 psi max, but it works seamlessly. No real tuning done, just the stock chip and about 30% larger injectors. Looking for a used Ford pattern .36 A/R turbine housing for a Garrett T3 to spin it harder. It will just max-out the MAF reading at 172 gr/sec Link to comment Share on other sites More sharing options...
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