TBI/CARB Hot-rodding

Welcome to the definitive Chrysler 2.2, 2.5 Non-turbo upgrade database.

Please, if you have anything you wish to add to this database e-mail me! This page is for those looking to upgrade their Chrysler TBI or Carbureted automobile.

A big thanks to these people that contributed to this database! Angleo Taylor, Bradley Miller, Cliff Sebring and Tom Byrne. See links to their websites at the bottom of the page.

A normally aspirated engine will generally make less power than a force inducted one (turbo or supercharged). Your best bet, if you have the cash, is to swap over to a factory turbo setup. If you cannot, then you have to live with this limitation and make do with the information on this page.. And if you don't have a healthy motor you're wasting your time.

Exhaust

A factory exhaust manifold is fine for most applications. A good cleanup with a Dremel tool can't hurt here. A header should only be used for full race applications. It is very impractical for street use, and generally has a short life. Some notes from Angelo Taylor... ..these headers are so long on the four door that sometimes they actually hit the track from rocking of the motor on launch, almost always they hit the cross member.. ..in under 1 year of street action they tend to break at the point where they are welded at the flange.. ..The hot ticket is to get the Mexican stock exhaust header.....it is a tubular one that uses the stock donut and attaching as do ours.. ..Another thing on exhaust, my car always ran a bit quicker with some type of exhaust on it compared to open header.. If you have the money, get a custom 2 1/4" or 2 1/2" system made up with a very free flowing muffler and cat. If your area allows it or you are using your car for off road use only, pitch the cat. Bradley Miller notes.. ...I went with 2 1/2 on the Shelby and it picked it up enough that my screwed up feedback carb caused a lean/bucking condition... A word on thermal wraps. I haven't used them on a non-turbo application, but on my turbo cars we had wrapped the exhaust manifold. Now Thermo-Tec notes this is a bad thing and they are correct. It results with a warped, cracked exhaust manifold that flexes so much it snapped the #1 exhaust stud right out of the head. proceed at your own risk...

Intake TBI: Work with what you have, it's all you can get. A good clean up with a Dremel tool to take the rough edges off can't hurt. Cliff Sebring sent me a tip... The carbureted intake flows better than the TBI one. I had a customer who was running a TBI setup who adapted a carb intake to his TBI unit and it went faster. I'm checking into the possibility of a spacer under the TBI unit for better airflow. Carb: The 86-up Intake manifolds are the best for general use. I am also looking into information on carb spacers. I had one made of wood that did not really seem to do anything..... Mopar Performance has a dual carb intake as well as a sidedraft Weber setup.

Weber intake PN: P4349086 ...the dual 40 DCOE Weber side draft carbs picked up my car from .75 to around a full second...

PN: P4452037 I don't have any information on the dual carb setup above but will make inquiries. Note: this product has been discontinued.

Fred Greer's dual carbed K-car wagon. One easy hp gain is disconnecting the coolant lines running under the intake for a cooler intake charge. This may cause drivability problems in cool weather. You could also try running water under the intake for an even cooler intake charge using an electric water pump and a cool can.

Camshaft

The best factory cam would be the 84-87 2.2/2.5 camshaft. It has the most lift and duration of all the non turbo cams. You can run the later roller cams if you wish; they do have a little smoother idle and make less noise but you will lose some duration (240 vs 234). It's a drop in; just use the roller followers and it will work in any 2.2/2.5 engine. Non stock cams may also annoy the computer on TBI applications. ..I suggest a 460/480 lift....any easily available duration.....cam sprocket is another thing... ....the 110 HP HO carb cars had a cam cog that was 2 degrees different than that of the regular carb 2.2s......the visual indication is that the hole on the timing point of the cog is oval instead of circular.. Tom Byrne writes into the database... I run the Mopar Performance 252 cam and it runs great. My car is a 2168 lb 84 Shelby Charger that is raced SCCA SOLO II class. Carb is a 5220 Holley, compression is 10:1, head is ported with stock valves and a 3 angle valve job. Exhaust is a stock manifold with 2 1/2" pipe, and a Flowmaster race muffler (Straight through design) which exits out just behind the drivers door. Pn: P4529320 Specs: 252-252 duration, 430 lift. NOTE: Do NOT use the turbo cams in a non turbo application!! You will lose horsepower. They have less duration and overlap than their non turbo cousins.

Cam keys are a good way to adjust your cam timing. Shelby retarded the camshaft 4 degrees in the carburated Shelby Chargers to make more high rpm hp. I prefer cam keys to "slip-slide" cam sprockets because of cost and its easier to duplicate results with the cam keys. PN: P4349650

Heads

The best flowing head is the 83-85 "G" casting head. It flows 10% more air than the 86-92 "782" head which makes about 10% more torque. The "G" head would be a good choice for a light car, while the "782" or fast burn head will be better for a heavier vehicle. Porting and polishing of cylinder heads is best done by a professional. Unless you have lots of practice and have done several, it's very easy to damage a head and make it unusable. Mopar Performance has two heads in their catalog: a mild ported head with 1 mm oversize valves and a more extensively ported head with much larger valves. I will try to get some hp numbers to see how much gain is acquired installing one of these units. ....I had a big valve head that was ported and 14/1 compression.....my car runs quicker with the stock valved head with a three angle valve job and 12/1 compression and port matching... ....these cars like efficiency of flow, not mass of flow on the heads.. LRE and Forward Motion also have ported heads for sale.

The Short Block

I'm not going to get into much detail about the various rod/crank/piston combos that could have been had over the years in the 2.2/2.5 family. Instead this will be a general tips section on what to do while playing around the insides of your short block. It bears repeating, a healthy motor makes hp- a tired one will not. If you have the money and are using your car for pure racing 12.5 to 14:1 compression seems to be the hot ticket. High-octane race gas of course is required. For street use, no more than 9.5:1 is recommended. Aftermarket pistons are readily available from TRW, Mopar Performance and J&E Pistons. Stock connecting rods are fine, replace the rod bolts with ARP units if you're having the rods resized (shotpeening is not a bad idea either). On oil pressure, experts recommend 7 to 10 psi of oil pressure for every 1000 rpm of engine usage. 7 psi + 6000 rpm = 42 psi 10 psi + 6000 rpm = 60 psi Also make sure you're using Mobil One oil- a synthetic motor oil will make more hp than a regular oil (frictional gains). Speaking of oil, a good baffled oil pan can help keep the oil in the pan where it belongs. Without one, the crank whips the oil up and costs hp. On a 440 Mopar V8 this is good for 15hp at 6000 rpm!

Costs range from $160 to $400 for a good oil pan. 2.5 liter owners can remove the balance shafts in the oil pan and pickup 10-14 hp for free- they are for secondary order vibrations and not needed. I have done several turbo and non-turbo cars with no ill effects. 88-95 2.5 Dakotas don't even come with them, no room in the oil pan. Just drop the oil pan, remove the 6 bolts holding the balance shafts in, cut the chain attached to the front of the crankshaft and remove it. Plug the oil feed hole, which is located next to the number 1 main cap, with a pipe plug (you will have to tap out the hole), reinstall the oil pan and your done. Another bonus is less engine noise and a pan that holds another quart of oil. A warning from Cliff... On the 2.5 86 to 88 motor swaps you need to install a distributor drive shaft with a fuel pump bump {out of your original 2.2} and when you install it you need to put it in 90 deg. out of time... because the longer 2.5 rod hits the fuel pump bump. On my car I moved the oil pump 90 deg also, so my distributor was correct but you could just rotate the wires one hole also... Of course this only applies if you are running a carb and wish to use a stock fuel pump. I would use an electric pump myself... ...note that the oil pump hole is oval while the one at the surface of the block that it mates to is round... ..take a die grinder and make the one on the block match the one on the pump... ...Ed Peters swears there is a 4 hp gain since pump does not sap as much power due to better oil flow.....I tried it on my carb Horizon and MAYBE picked up .10... ...not really worth the effort... Unless of course you have the motor apart and have a garage... every little bit helps..

Ignition

No computers are available for the TBI cars. ND Performance is working on this; a custom computer can be programed for your needs. (505) 458-6024 Computers are available from Chrysler for carbureted applications. P4529864 1978-1982 P4529865 ..........1983 P4529866 ..........1984 P4529867 1985-1987 The Mopar Performance unit does have a good bit of ET improvement over the stock unit....compared to the 110 HP Shelby unit it has less......in my case (110 hp) the MP unit was worth initially .5 in the 1/4 mile..but as air temperatures rose, the improvement becomes less and less... ...starting out at 50 degrees it was the 1/2 second improvement, but as the temps hit 80 it leveled off to the same elapsed times that I had with the stock unit.....on a non Shelby car the ET would still be better. Stock spark plugs work excellent; RN12YC or for a colder plug, RN9YC. .35 to .40 gap works just fine, do not go over .40 ...I NEVER had luck with Splitfires or Bosch Platinums......nothing wrong with stock Champions. The stock ignition coil works great as does the stock (mopar) spark plug wires. If you must use aftermarket plug wires get Magnacore wires or make a set from Moroso spiral core. Do NOT use solid core wires! modern computers do not tolerate the electronic noise they generate!

Fault code charts for Carb and TBI Carb and TBI Vacuum Diagrams for Carb and TBI 84 CARB 85 CARB 86 CARB 85 TBI 86 TBI 87 TBI 88 TBI

Fuel System: Carb

Well, the plus of running a carburetor is that you can adjust your fuel curve to your liking. The down side of course is that you have to do it yourself! plus, you lose the smoothness of fuel injection. GET AN O2 GAUGE! ITS THE BEST WAY TO TUNE YOUR CARB! I have been using one on my 1970 GTX for over 7 years. Carb tuning and rejetting can be done in as little as an afternoon. There are two basic 2.2 factory carburetors. The Holley 6520 is a feedback carb and the 5220 is not. The 5220 flows a little more air than the 6520. Caravans, Rampages and 87 2.2 Dakotas came with the 5220. The 5220 is also in the Mopar Performance Catalog. PN: P4286772 I prefer the feedback carb myself, due to the fact the computer can still adjust your fuel curve at cruise for best gas mileage. ...the non feed back carb flows more CFM (I have heard 100) but I do know that the non feed back carb is better for bracket racing and consistancy.....it has a power valve that can be adjusted to open a bit sooner....on the top of the carb is a tiny metal cap (1/4 dia) that can be removed and under that is a hex screw that is directly over the powervalve....simply turn the screw in one full turn (per Ed Peters)....or 1/2 turn (per me)......this makes the powervalve open earlier.....for even better consistancy you would open the carb and plug off where the power valve is screwed in.....you MUST richen up the secondary jetting when you do this....... Jetting.....I run rather lean for drag racing with a 225 primary and 335 secondary... ...for next year I will go to a 355 secondary since I have now removed and pluged the powervalve......for more power go richer yet.........hint....the old VW (1.7) powered L bodies had huge secondary jets in their carbs.....bigger than the jetting kit that is available from Mopar Performance. 2.2 carb jetting package PN: P4286777 ...at one time I put a Holley 500 cfm 2 barrel with mechanical secondary linkage on a 81 Horizon, it ran absolutely no quicker, and fuel mileage dropped a lot!!! We used a 1 1/2" wooden spacer to mate it to the intake...

Mopar Performance has two carb packages. One is the downdraft Weber, which will bolt on your current intake mainifold and makes good power over your stocker. PN: P4349300 Note: this may be a discontinued part number. The other package is the Weber sidedraft dual carb and intake kit which makes max power with a carbureted 2.2/2.5. You will need the inake and two carbs. PN: P4349086 and P4349087 x2 Mopar Performance recommends 2.5 to 3 psi of fuel pressure for the Weber sidedraft carburetors.

..the dual 40 DCOE Weber side draft carbs picked up my car from .75 to around a full second... ...you may need to relocate the power steering pump for installation (my car was manual)... ..they have a problem with heat soak from the header, I suggest a heat shield be fabricated and placed between the header and the carbs... ...these things have a real neat sound when run with no air filters!!! I had the dual 40mm Webers and that will absolutely make you . . . well . . . you know . . when you turn the key the first time. . . Touch the throttle and you'll need an underware change -- it will rev very freely and quickly. This change alone is good for about an easy 3/4+ second difference. Be sure to use a fuel pressure regulator on the dual 40mm Webers. If using the stock style carburetor take a 5/16 fuel filter and put it inline with your charcoal canister. This will keep chunks of charcoal from the canister out of your float bowl. An electric fuel pump will also help prevent vapor lock in hot weather. Chrysler even had a pump package TSB to repair this problem. Make sure to remove the stock pump, block off the fuel pump hole in the block and use a fuel pump regulator.

Fuel System: TBI

TBI guys have it the hardest- there is very little you can do to fool around with your fuel system. 86-87 cars have the worst computers as they are very limited. They don't have as much leeway as the 88 and up computers when it comes to injector size and other parameters... Here are some tips and tricks... Try an injector from a larger engine (i.e. a 2.5 injector if you have a 2.2). An adjustable fuel pressure regulator or pinch valve. (careful they only run at 15 psi) Plug in a loose coolant sensor (when racing); the computer thinks the engine is colder than it is, so it richens up the fuel curve. ND Performance (505 458-6024) makes custom computers. Call him with your needs.

Fuel System: Port Fuel Injection This here is the deal. Momma Mopar never made a PFI non turbo 2.2 in the USA. They did however make a 2.5 PFI called the Flexi-Fuel vehicle in 89 or 90. It was a spirit that would run on gas or methanol or any combo in between. It was used, if memory serves, in a government test fleet in limited numbers. They also made/make in mexico a PFI 2.2 combo. Behold the only 2.2 PFI non-turbo in the USA!

Got bored one day seeing the Mighty K sitting with no motor in it. took a tbi engine that was hiding under a tarp and slapped an 89 2.2 turbo intake on it, welded up the egr tube and stuffed it in. Runs good but the spark curve is for a turbo car and it takes a dive at WOT. I have a custom computer on its way from ND Performance (505 458-6024) and I will let ya know how it runs this winter. You know what they say, idle hands are the devils tools!

Tips and Tricks

Get a cyberdyne air/fuel gauge, it makes tuning a snap! part number 7009 - it's about $30 from summit racing.. it's not just for turbos! If you have a carbureted car and can get away with it, lose the air pump... ..Couple of horsepower hiding there. Weight is bad -100 lbs is equal to 10 hp or 1/10 sec in the quarter mile. So you can lose weight or make more power- it's easier to lose weight and parts last longer. Some examples: get a lighter battery (10 lbs), light weight seats (40-90 lbs), lightweight wheels; empty your trunk-you would be suprised how much weight is lurking in there; holesaw the bumpers behind the covers where it can't be seen; pitch the a/c compressor. Hell, if you're desperate scrape the undercoating off the car. Now, if you managed to pull 200 lbs from your car you just gained 20hp. Simple isn't it?

REPEAT AFTER ME - THERE IS NO REPLACEMENT FOR DISPLACEMENT Drop in an 89-up 2.5 in a carbureted car and enjoy the extra ponies. Just swap over the intake to a carb model and away you go. And remember to pull the balance shafts before installing the engine. This can also be done with a TBI car as long as the computer is swapped with the engine and fuel injector. 86-88 2.5's had a taller deck height so they might be a tighter fit in smaller cars; plus the exhaust sits up 11mm higher. Install a manual transmission if you can and have the tech know how; there are less hp losses with a manual and you have 2 extra gears to work your powerband PLUS your gas mileage goes up as well as the top speed of the car. Install a turbo clutch and flywheel; it has a 15mm larger disk and you may never have to change a clutch again. A tip to carb owners using the stock air cleaner setup. Mopar Performance says to stack 3 gaskets at the air cleaner to carb junction for better air flow. Absolute quickest and cheapest ET gains on these cars, get rid of the air filter assembly. Run a ram air hose to the carb, but make sure you use some sort of fine wire mesh air filtration. I made a very tiny screen frame that fit inside the stock air filter assembly, then plugged all openings to the air filter box except where the air hose comes from the computer. That is where I hooked up the ram air...very easy to do.. Drop in a 185 degree thermostat for more power, cooler running and better detonation resistance. Do not install a 160 thermostat- excessive wear of the rings will result. Short on cash? - get a turbo exhaust system from a junk car of the same model. Cut the flange off up front, weld on your tbi/carb exhaust flange and it's a bolt on.

For those of you considering a RWD conversion... Mopar Performance used to have a 2.2/2.5 bellhousing kit in the catalog. It was just stock Dakota parts that were bundled in a package.

Spending Money Well, you can get an underdrive pulley which is good for 10-11hp for $75. K&N air cleaners are mandatory equipment. they are cheap and good for a 1-2% horsepower increase.

you may never have to replace an air filter again. Another good choice would be a nitrous oxide kit, 50 hp at the touch of a button. Only problem is when the bottle runs out; but 50hp of juice lasts a long time. The carb part number from NOS systems is: 05011 The TBI part number is: 05118 note: I do not know if this is for 84-85 E.F.I. or 86-92.

714-546-0592 ICE Nitrous systems used to have a nice kit for the Carb 2.2, but I think they are no longer in business.

The part number was: 30023 1-800-845-2383 Mopar Performance used to list a supercharger for the 2.2 engine (P4349478) Development work was done at the Carol Shelby Performance center, and it was manufactured by B&M for Chrysler. It was also listed in the B&M catalog, part number 90601

Dealer cost on this in 1987 was $1400! It made with the stock carb 130hp@5200 RPM. With the Weber carb (PN P4349300) the hp jumped to 155@5200 RPM.

Links Angleo Taylor Bradley Miller Tom Byrne Thanks for stopping in!