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4.9L OHV Short-Ram Intake?


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So I want to make a short-ram intake. I want to get the throttle response and slightly better mileage.. I have also heard it 'can' "increase" performance. But whatever. That and the sound is.. pretty.

I would also like to know if there are other recommendations for this engine.. I have it completely stock in my 1995 Sedan DeVille. I would like some more performance from it and I have heard that on this engine.. most performance mods add some minor fuel mileage.

Anybody have any 'caddyinfo'? :lol:

BTW, I'm 17 and LOVE my '95 DeVille. IDFC if people call it an old man's car. When they ask me why I drive a caddy I tell them it's because they don't have the balls to.

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Look at the intake that was on the 1992 Cadillac Allante for hints. That was a 4.5L OHV engine, but was tuned for power.

Bruce

2016 Cadillac ATS-V gray/black

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As Bruce suggests your best bet might be to try and source an Allante intake

They looked like this:

!Bc%20ikgw!2k~$(KGrHqMH-D8ErGJ%20HbDNBK2

And there is one for sale, right now, on ebay for $275.

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Easin' down the highway in a new Cadillac,

I had a fine fox in front, I had three more in the back

ZZTOP, I'm Bad I'm Nationwide

Greg

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As Bruce suggests your best bet might be to try and source an Allante intake

They looked like this:

!Bc%20ikgw!2k~$(KGrHqMH-D8ErGJ%20HbDNBK2

And there is one for sale, right now, on ebay for $275.

Now I don't want to sound stupid.. on my engine where would the "pipes" connect to? and would that just connect to my current intake filter box or would it come with a new one?

Edited by SiK GambleR
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I wouldn't want to say for sure that an Allante 4.5 intake would work on a 4.9. I suppose that there's a chance that the ports wouldn't match up. The "pipes" in the picture are a part of the upper part of the manifold, and there would be a lower part as well which further carried the air down to the heads and has the injectors in it. Perhaps there is a separate piece to cover the valley of the engine underneath the manifold. Cool, filtered air would also have to be plumbed to that central location, close to the firewall in the case of the pictured manifold. Getting the Allante's airbox would be a good bet. Any sensors in your car's original intake would have to be adapted to the new one for the engine to run right. In this case, the throttle body gets moved, so you'd have to adapt the throttle cables and vacuum lines as well.

Moving an Allante intake to a Deville would be a whole lot like work for not much gain. Your time and money would probably be better spent putting on some Flowmaster mufflers. That would have about as much performance gain as anything else that is easy, and would add a lot of V8 rumble and bark to the exhaust.

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I wouldn't want to say for sure that an Allante 4.5 intake would work on a 4.9. I suppose that there's a chance that the ports wouldn't match up. The "pipes" in the picture are a part of the upper part of the manifold, and there would be a lower part as well which further carried the air down to the heads and has the injectors in it. Perhaps there is a separate piece to cover the valley of the engine underneath the manifold. Cool, filtered air would also have to be plumbed to that central location, close to the firewall in the case of the pictured manifold. Getting the Allante's airbox would be a good bet. Any sensors in your car's original intake would have to be adapted to the new one for the engine to run right. In this case, the throttle body gets moved, so you'd have to adapt the throttle cables and vacuum lines as well.

Moving an Allante intake to a Deville would be a whole lot like work for not much gain. Your time and money would probably be better spent putting on some Flowmaster mufflers. That would have about as much performance gain as anything else that is easy, and would add a lot of V8 rumble and bark to the exhaust.

!!!! thank you!

What I was thinking was .. I would remove the box but leave the current (idk what to call it) connected to the top of my engine, then make a straight pipe to a spot for my cone where I can get alot of air, put a cone, then leave it like that.. =D

basically making a custom CAI ... for like a total of 40 bucks. Only thing is.. I'd need to make a dam for around the cone, but that shouldn't be so hard.

Edited by SiK GambleR
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Davek has the best suggestion, with free-flow mufflers. I would add a low-restriction cat (be sure and get an OBD-compliant one to avoid problems later with emissions inspections). This can get you, realistically, about 5% on torque and horsepower, with some increase in gas mileage too.

If you do want to add a high-performance fuel injection, the Allante unit is likely to be your best bet. AFAIK, the only big difference between the 4.5 liter and the 4.9 liter is the stroke, and unless they changed the deck height the intake assembly should bolt right up. It may be higher than the stock unit and the air box will move, so you will have to deal with that. I would just get a new flex hose from the throttle body to the air intake. I would just try it with no mods to the PCM and see how it works. On the Allante, the difference was 200 hp, vs. 180 hp (or 190 hp for the last year) for other 4.5 liter engines. The 4.9 was rated at 200 hp but Cadillac left the 4.5 with that intake on the Allante for reasons that I will leave to your imagination. I don't know about any cam differences between the Allante and other 4.5 liter Cadillac engines. If this works out for you without glitches or confusion in the PCM, it can get you 5% to 10% on horsepower; this is done by moving resonances around and adding an intake resonance high in the RPM range, so the car will drive differently, and torque probably won't improve -- but the 4.9 liter has plenty of torque.

Unless the air intake is a high-flow cold-air like the factory Northstar, you might look into an aftermarket setup that can add that too, but don't jump on that because Cadillacs usually do have an intake and air cleaner that can't be matched, much less surpassed, by aftermarket add-ons for either overall performance or keeping dirt and dust out of your engine.

With a free-flow exhaust and the Allante intake, you should run about 220 hp or more, enough for a real difference in feel and driveability, particularly at the top of the RPM range where the Allante intake resonance will give you that surge just before shift.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Davek has the best suggestion, with free-flow mufflers. I would add a low-restriction cat (be sure and get an OBD-compliant one to avoid problems later with emissions inspections). This can get you, realistically, about 5% on torque and horsepower, with some increase in gas mileage too.

If you do want to add a high-performance fuel injection, the Allante unit is likely to be your best bet. AFAIK, the only big difference between the 4.5 liter and the 4.9 liter is the stroke, and unless they changed the deck height the intake assembly should bolt right up. It may be higher than the stock unit and the air box will move, so you will have to deal with that. I would just get a new flex hose from the throttle body to the air intake. I would just try it with no mods to the PCM and see how it works. On the Allante, the difference was 200 hp, vs. 180 hp (or 190 hp for the last year) for other 4.5 liter engines. The 4.9 was rated at 200 hp but Cadillac left the 4.5 with that intake on the Allante for reasons that I will leave to your imagination. I don't know about any cam differences between the Allante and other 4.5 liter Cadillac engines. If this works out for you without glitches or confusion in the PCM, it can get you 5% to 10% on horsepower; this is done by moving resonances around and adding an intake resonance high in the RPM range, so the car will drive differently, and torque probably won't improve -- but the 4.9 liter has plenty of torque.

Unless the air intake is a high-flow cold-air like the factory Northstar, you might look into an aftermarket setup that can add that too, but don't jump on that because Cadillacs usually do have an intake and air cleaner that can't be matched, much less surpassed, by aftermarket add-ons for either overall performance or keeping dirt and dust out of your engine.

With a free-flow exhaust and the Allante intake, you should run about 220 hp or more, enough for a real difference in feel and driveability, particularly at the top of the RPM range where the Allante intake resonance will give you that surge just before shift.

So, if i understood correctly.. If I can afford the allante thing, I may as well try it as a fun sunday project.. but in reality the 4.9 had a fairly free flowing intake so I wouldn't see the improvement I would like?

As for an exhaust.. I want to do this myself, and I have no idea how to do an exhaust or what to buy.. could you link me to what you would recommend? My uncle could probably help me install it.

I just want to make this car feel like mine and have fun building it up and getting some more fun out of it. I love my deville!

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INTAKE

The intake has three things to consider: The fuel injection, the intake manifold and throttle body assembly, and the air intake and air cleaner.

The fuel injection is the wiring, fuel rails (high pressure fuel lines), injectors, fuel pressure regulator, and fuel return line. I would keep these from your old car. Use the ones from the Allante if the parts from your old car won't fit.

The intake manifold and throttle body assembly is what we have the pictures of. It bolts to the heads, seals the lifter valley, and includes the injector stacks, a plenum chamber, and a throttle body. This includes the enhanced injector stacks that you want, based on your first post here. This would come from the Allante parts from eBay (or wherever).

The air intake is the flex hose and air cleaner. In the Northstars of the 1995 model year, the air cleaner mounts right behind the radiator mounts and gets its air through a passage behind the left headlight; this is a cold air intake. There is a flex hose from this to the fuel injection intake.

MIX AND MATCH INTAKE PARTS

I'm going to wing this summary because I don't have hands-on experience with the Allante, but lots of others here do. They will likley chime in if I'm off base here.

You should try to use your existing fuel injection components. The Allante intake manifold and throttle body assembly will bolt to your heads and you will mount your fuel injection onto the Allante intake manifold. You may need some parts like the fuel rails off the Allante to make everything fit. Try to use your existing fuel injectors and fuel pressure regulator. If you have to switch to the Allante fuel injection lock-stock-and-barrel, that's OK. You will hook up your existing throttle linkage, IAC stepping motor contacts, etc. to the Allante throttle body; if that doesn't work out try to use your old throttle body.

EXHAUST

You will need to weld stainless steel to change any of your exhaust components. Your exhaust system is an all-stainless-steel system from manifold to tips, unless someone has changed pieces and cheaped out the replacements. The usual procedure for switching mufflers is to use your old exhaust tips and weld the new mufflers in place of the old, perhaps with short extensions to make them fit. The mufflers and such are not expensive, so long as you use your old tips and Y-pipe.

The catalytic converter can be expensive if you buy a bolt-in exact fit, and those are hard to find in free-flow versions too. General replacement OBD-II compliant cats are available; I have one myself. Buying these and welding your old flanges and oxygen sensor bungs should run about $125 for everything.

I would recommend finding a Midas or Meineke shop that does stainless steel welding and let them do it. Just make sure that the particular shop you go to doesn't have all pickups and RVs in the lot; there are a lot of muffler shops out there in the business of selling aluminized steel Flowmasters to the redneck-rider set and an iron weld on a stainless steel system will rust away after a year or two in the salt belt, dropping your stainless steel muffler on the street. Ifs you are an experienced welder and are comfortable with stainless steel tubing, then of course do it yourself. I suppose you can saw-and-clamp, too, if you like; then you can do it yourself without welding, just be sure and use stainless steel clamps, too. Borla, Flowmaster, Flowmax, Magnaflow, and just about all of them now sell stainless steel turbo or super-turbo mufflers in your size, which is probably 2 1/4" in and out, center-in, offset-out.

You can't get out of welding if you want a high-flow cat. Mine is a Magniflow 94109, which is 49-state OBD certified (in CA, you're out of luck for high-flow cats if you want to be emissions legal). Link:

It doesn't mention OBD compliance on the linked page but it does on the box; if in doubt check the manufacturer's web page or call them before buying.

I did my exhaust system a few years ago because I was rear-ended; Borla was out-of-stock with super turbos so I got Borla XS series straight-through mufflers. I like the sound, as does my wife and friends; some say it is too loud for a Cadillac but I find that these guys have another agenda, such as sauerkraut burners. And, I have an Eldorado with a Northstar, you have a Deville with a 4.9 liter. You may want to do your own research on what cat and muffler is best for your car.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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INTAKE

The intake has three things to consider: The fuel injection, the intake manifold and throttle body assembly, and the air intake and air cleaner.

The fuel injection is the wiring, fuel rails (high pressure fuel lines), injectors, fuel pressure regulator, and fuel return line. I would keep these from your old car. Use the ones from the Allante if the parts from your old car won't fit.

The intake manifold and throttle body assembly is what we have the pictures of. It bolts to the heads, seals the lifter valley, and includes the injector stacks, a plenum chamber, and a throttle body. This includes the enhanced injector stacks that you want, based on your first post here. This would come from the Allante parts from eBay (or wherever).

The air intake is the flex hose and air cleaner. In the Northstars of the 1995 model year, the air cleaner mounts right behind the radiator mounts and gets its air through a passage behind the left headlight; this is a cold air intake. There is a flex hose from this to the fuel injection intake.

MIX AND MATCH INTAKE PARTS

I'm going to wing this summary because I don't have hands-on experience with the Allante, but lots of others here do. They will likley chime in if I'm off base here.

You should try to use your existing fuel injection components. The Allante intake manifold and throttle body assembly will bolt to your heads and you will mount your fuel injection onto the Allante intake manifold. You may need some parts like the fuel rails off the Allante to make everything fit. Try to use your existing fuel injectors and fuel pressure regulator. If you have to switch to the Allante fuel injection lock-stock-and-barrel, that's OK. You will hook up your existing throttle linkage, IAC stepping motor contacts, etc. to the Allante throttle body; if that doesn't work out try to use your old throttle body.

EXHAUST

You will need to weld stainless steel to change any of your exhaust components. Your exhaust system is an all-stainless-steel system from manifold to tips, unless someone has changed pieces and cheaped out the replacements. The usual procedure for switching mufflers is to use your old exhaust tips and weld the new mufflers in place of the old, perhaps with short extensions to make them fit. The mufflers and such are not expensive, so long as you use your old tips and Y-pipe.

The catalytic converter can be expensive if you buy a bolt-in exact fit, and those are hard to find in free-flow versions too. General replacement OBD-II compliant cats are available; I have one myself. Buying these and welding your old flanges and oxygen sensor bungs should run about $125 for everything.

I would recommend finding a Midas or Meineke shop that does stainless steel welding and let them do it. Just make sure that the particular shop you go to doesn't have all pickups and RVs in the lot; there are a lot of muffler shops out there in the business of selling aluminized steel Flowmasters to the redneck-rider set and an iron weld on a stainless steel system will rust away after a year or two in the salt belt, dropping your stainless steel muffler on the street. Ifs you are an experienced welder and are comfortable with stainless steel tubing, then of course do it yourself. I suppose you can saw-and-clamp, too, if you like; then you can do it yourself without welding, just be sure and use stainless steel clamps, too. Borla, Flowmaster, Flowmax, Magnaflow, and just about all of them now sell stainless steel turbo or super-turbo mufflers in your size, which is probably 2 1/4" in and out, center-in, offset-out.

You can't get out of welding if you want a high-flow cat. Mine is a Magniflow 94109, which is 49-state OBD certified (in CA, you're out of luck for high-flow cats if you want to be emissions legal). Link:

It doesn't mention OBD compliance on the linked page but it does on the box; if in doubt check the manufacturer's web page or call them before buying.

I did my exhaust system a few years ago because I was rear-ended; Borla was out-of-stock with super turbos so I got Borla XS series straight-through mufflers. I like the sound, as does my wife and friends; some say it is too loud for a Cadillac but I find that these guys have another agenda, such as sauerkraut burners. And, I have an Eldorado with a Northstar, you have a Deville with a 4.9 liter. You may want to do your own research on what cat and muffler is best for your car.

THANK YOU!

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