'88 Formula LM4 5.3 swap
#101
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Re: '88 Formula LM4 5.3 swap
I did some digging cause I thought mine was low as well. From what I could find the Ohm put outs from the third gen and fourth gen sensor are the same but the gauges are different. So full pull on the thirdgen gauge is only 60 psi but the sensor is thinking it is telling you 80 psi. So look at your gauge as 40 and 80 instead of 30 and 60. Mine seemed to read a little low too until I figured that out. PSI is always fine on mine but it is a little jumpy. Not sure the cause, might be a bad sensor, not sure what else would make it hop like it does.
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Re: '88 Formula LM4 5.3 swap
Throw on a mechanical gauge to verify accuracy. I run Speedhut Gauges (electric senders) and I verified my electric oil PSI speed hut gauge is dead accurate with my Stewart warner mechanical gauge. You should always take the stock gauge readings like a grain of salt... they are by no means accurate. If you dont have a oil psi mech gauge... throw on a $15 harbor freight fuel pressure gauge or equivalent and call it a day just to verify differences.
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I'm a little behind, so didn't see this when you posted it. I know you have already done something, but the simple solution when using a 4th gen LS1 cable is to take the accelerator pedal out, put the arm in a vice, and put more bend into it. I used a big crescent wrench on the part not in the vice to get a little more leverage.
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Re: '88 Formula LM4 5.3 swap
I ended up merging the 3rd and 4th gen cable, works great, WOT works and it doesn't bind, so I'm happy. Throttle pedal is much easier to push than it was with TBI.
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Re: '88 Formula LM4 5.3 swap
I did some digging cause I thought mine was low as well. From what I could find the Ohm put outs from the third gen and fourth gen sensor are the same but the gauges are different. So full pull on the thirdgen gauge is only 60 psi but the sensor is thinking it is telling you 80 psi. So look at your gauge as 40 and 80 instead of 30 and 60. Mine seemed to read a little low too until I figured that out. PSI is always fine on mine but it is a little jumpy. Not sure the cause, might be a bad sensor, not sure what else would make it hop like it does.
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Re: '88 Formula LM4 5.3 swap
Hopefully this method is starting to catch on around here because it is such good sense. This would be a good update to the LS swap sticky.
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Re: '88 Formula LM4 5.3 swap
One of these days you should look at the link I provided.
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#112
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Re: '88 Formula LM4 5.3 swap
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Re: '88 Formula LM4 5.3 swap
Speedo is correct, rolling at 25mph, matted the throttle. Love how this thing sings past 6k rpm, looks like ill need more tach. Lol
#115
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Re: '88 Formula LM4 5.3 swap
Small update, swapped to factory third gen 1 wire oil pressure sending unit, makes the gauge look a little better. Still need exhaust, Im actually thinking of getting a flowmaster catback after listening to several ls1 exhaust clips on youtube. Lots of people hate on flowmaster but I like it for some reason.
#116
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Re: '88 Formula LM4 5.3 swap
I'm running the summit catback. Uses a chambered muffler as well. Pretty good sound. I'm not a fan of flowmaster. I just swapped the summit muffler for a dynomax SS ultra flow as they are only of the best sounding mufflers to me, and they flow much more than chambered, basically a straight through perforated SS core like Magnaflow. I have yet to start it up tho with the new muffler and engine upgrades.
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Re: '88 Formula LM4 5.3 swap
I was curious how the summit catback sounds, it has a good price.
At one point I had a dynomax on the car when it was still 305 powered, I liked it ok, Im sure it'd be quite a bit different with an LS though. Im not a fan of the flowmaster drone, but I like the growl and pop they tend to have.
At one point I had a dynomax on the car when it was still 305 powered, I liked it ok, Im sure it'd be quite a bit different with an LS though. Im not a fan of the flowmaster drone, but I like the growl and pop they tend to have.
Last edited by fiveoformula; 04-04-2017 at 03:30 PM.
#118
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Re: '88 Formula LM4 5.3 swap
The summit catback sounded really good for a chambered muffler. Quality was there as well. They are rebranded hooker heartthrob systems. I would have been happy with the summit catback but I upped the power by 100hp over my original so I wanted a more freeflowing muffler. Flowmasters are very restrictive.
Heres a video of mine on the car, this is with my 5.3 and supercharger just idling but it should sound just like yours at idle. My engine was bone stock.
The Dynomax mufflers come in many flavors... they have walker (OE quiet), super turbo, ultra flow, SS ultra flow etc. The muffler that comes in the dynomax catback is not the same as the Fbody specific ultra flow SS muffler. The Catback version has a 2.75" inlet and they muffler swap muffler is 3" inlet.
Heres a video of mine on the car, this is with my 5.3 and supercharger just idling but it should sound just like yours at idle. My engine was bone stock.
The Dynomax mufflers come in many flavors... they have walker (OE quiet), super turbo, ultra flow, SS ultra flow etc. The muffler that comes in the dynomax catback is not the same as the Fbody specific ultra flow SS muffler. The Catback version has a 2.75" inlet and they muffler swap muffler is 3" inlet.
#119
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Re: '88 Formula LM4 5.3 swap
That sounds pretty good, (sorry for the delayed response). Still living with straight pipe. I might consider that summit kit since it's such a good price too. Have any exhaust clips with revving?
#120
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Re: '88 Formula LM4 5.3 swap
That is a nice looking car, man! I like those ROH (?) wheels.
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Re: '88 Formula LM4 5.3 swap
Thank you! They're actually late 4th gen TransAm speedlines, normally they are polished but I plasti dipped them black. I'd like to powder coat them one day.
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Re: '88 Formula LM4 5.3 swap
Sorry, no videos of it Reving. But I have been driving the car with the dynomax ultra SS muffler swapped in and the sound is much different. The dynomax is a much throater sound and it's a bit louder on the throttle. The summit chambered muffler does sound pretty good tho but the dynomax gives it alittle more of a angry sound and it should be less restrictive. Dynomax is about 2" longer tho than the summit muffler so I had to cut the exits pipes so they would line up with my center exhaust. But the dynomax is a good bit thinner like 1-1.5" thinner so it tucked up nicely. I was very pleased with the summit kit tho so don't hesitate as everything seemed good quality except the clamps.
#123
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Re: '88 Formula LM4 5.3 swap
Now that I have ran a couple tanks of fuel, I figured out I get 17mpg around town without driving nice!
My 350/T5 got around 12-13 in town and 19-20 on highway road trips.
Just thought Id share, its nice to get some decent mileage. lol
Once I get some exhaust and tires, I'll visit my friend in Seattle who tunes with HPtuners, so we can really dial it in and see what numbers I can put down on the dyno.
My 350/T5 got around 12-13 in town and 19-20 on highway road trips.
Just thought Id share, its nice to get some decent mileage. lol
Once I get some exhaust and tires, I'll visit my friend in Seattle who tunes with HPtuners, so we can really dial it in and see what numbers I can put down on the dyno.
#124
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Re: '88 Formula LM4 5.3 swap
Given that its a stock 5.3, the stock LS1 intake is going to hurt power. Stock 5.3 with truck intake will put out 275-300hp at the crank. But since you have a free flowing exhaust you could pick up a few more ponies. BUt I would be shocked if you making more than 300hp at the crank. Throw in a cam and ditch the stock LS1 intake and you would pick up alot more power.
#125
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Re: '88 Formula LM4 5.3 swap
Yeah, I know the LS1 manifold sucks. It also has the smaller valve 862 heads.
This 2004 LM4 is rated at 295hp at the crank, picks up a little more with long tubes and the LS6 cam. I'm more curious about the number than anything, I know its not a monster.
I dyno'd my dad's C5 LS1 auto corvette a few years back, made 275rwhp, if I can meet or beat that, Ill be ok for a while.
I also once dyno'd my stock 305 at like 129rwhp too, it was running super lean though, due to a dying fuel pump. lol
Next stage might be a bigger cam and worked over heads.
This 2004 LM4 is rated at 295hp at the crank, picks up a little more with long tubes and the LS6 cam. I'm more curious about the number than anything, I know its not a monster.
I dyno'd my dad's C5 LS1 auto corvette a few years back, made 275rwhp, if I can meet or beat that, Ill be ok for a while.
I also once dyno'd my stock 305 at like 129rwhp too, it was running super lean though, due to a dying fuel pump. lol
Next stage might be a bigger cam and worked over heads.
#126
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Car: 1988 Formula Firebird
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Re: '88 Formula LM4 5.3 swap
Seem to be running into problems with power steering.
Lost assist completely with no leaks, no noises or any other symptoms.
Read up on the ol interweb to find that it's common for reman LS1 pumps to get clogged and make the fluid bypass essentially.
Well I took my pump apart, cleaned the jet and pressure relief orifice (not sure if these are correct names for these parts) but anywho, I slapped it all back together and got power assist back... For a few days, then lost it again.
Both times I have lost power steering, it's been after some high RPM shenanigans, so I'm fairly certain that has something to do with it getting clogged.
Anyone ever have similar issues?
Thinking about getting a different reman pump and trying my luck with that.
Lost assist completely with no leaks, no noises or any other symptoms.
Read up on the ol interweb to find that it's common for reman LS1 pumps to get clogged and make the fluid bypass essentially.
Well I took my pump apart, cleaned the jet and pressure relief orifice (not sure if these are correct names for these parts) but anywho, I slapped it all back together and got power assist back... For a few days, then lost it again.
Both times I have lost power steering, it's been after some high RPM shenanigans, so I'm fairly certain that has something to do with it getting clogged.
Anyone ever have similar issues?
Thinking about getting a different reman pump and trying my luck with that.
#127
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Re: '88 Formula LM4 5.3 swap
What about installing a filter on the return side to catch debris.
#128
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Re: '88 Formula LM4 5.3 swap
Just ordered a filter part number 20-0038F.
Turns out its a common enough problem that even the parts stores computer has a note recommending the installation of a filter.
So I'll do that and clean the pump out again, hopefully that's the cure.
Turns out its a common enough problem that even the parts stores computer has a note recommending the installation of a filter.
So I'll do that and clean the pump out again, hopefully that's the cure.
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Re: '88 Formula LM4 5.3 swap
Car looks great, think I'd keep the wheels silver or polished tho.
#130
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#132
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Re: '88 Formula LM4 5.3 swap
Yeah, I know the LS1 manifold sucks. It also has the smaller valve 862 heads.
This 2004 LM4 is rated at 295hp at the crank, picks up a little more with long tubes and the LS6 cam. I'm more curious about the number than anything, I know its not a monster.
I dyno'd my dad's C5 LS1 auto corvette a few years back, made 275rwhp, if I can meet or beat that, Ill be ok for a while.
I also once dyno'd my stock 305 at like 129rwhp too, it was running super lean though, due to a dying fuel pump. lol
Next stage might be a bigger cam and worked over heads.
This 2004 LM4 is rated at 295hp at the crank, picks up a little more with long tubes and the LS6 cam. I'm more curious about the number than anything, I know its not a monster.
I dyno'd my dad's C5 LS1 auto corvette a few years back, made 275rwhp, if I can meet or beat that, Ill be ok for a while.
I also once dyno'd my stock 305 at like 129rwhp too, it was running super lean though, due to a dying fuel pump. lol
Next stage might be a bigger cam and worked over heads.
Fun fact the 862 heads are the same as the 5.7 heads, just smaller chambers and smaller intake valve. The runners are basically the same up to the valve. light port work on the 862s would be beneficial and removal of the swirl ramps.
#133
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Re: '88 Formula LM4 5.3 swap
Yes sir.
2004 aluminum 5.3
LS6 cam and springs
untouched stock 862 heads,
stock bottom end with supposedly 80k miles
LS1 intake, injectors, fuel rails
currently running a truck tune with stock LS1 spark mapping
What intake manifold would you recommend? LS6? aftermarket?
#134
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Re: '88 Formula LM4 5.3 swap
Yes sir.
2004 aluminum 5.3
LS6 cam and springs
untouched stock 862 heads,
stock bottom end with supposedly 80k miles
LS1 intake, injectors, fuel rails
currently running a truck tune with stock LS1 spark mapping
What intake manifold would you recommend? LS6? aftermarket?
2004 aluminum 5.3
LS6 cam and springs
untouched stock 862 heads,
stock bottom end with supposedly 80k miles
LS1 intake, injectors, fuel rails
currently running a truck tune with stock LS1 spark mapping
What intake manifold would you recommend? LS6? aftermarket?
not bad! The LS6 cam is an upgrade for sure. You would make more power with a simple aftermarket cam grind and retain stock idle and vacuum like a 205/210. The LS6 cam has more duration but the lift and lobe and ramp rates are way different. I run a Cam motion custom cam 216/228 .561/.561 114.5+5.5 and its stupid how much power it makes from like 2k up to 6k. They said I should see 80hp gains on the cam along with my setup (low boost) but keep my driveability. So far it hasn't dissapointed and I just took it 1.5 hrs cruising between 1500-2300rpms at 60-85mph and it was fine. But it only makes 14" of vacuum on my 5.3.
Your aluminum 5.3 has flat top pistons so you get a little bump on compression and the stock cam was a smidge more duration than a normal 5.3 but you changed the cam out anyways.
Your stock heads are fine, you could do a mild port and leave the valves or upgrade to the large 5.7 valve. Or get an aftermarket 5.3 head. But mild cleaning up and a good valve job can get you decent gains for cheap.
If your trying to stay with a low rise intake your limited to car style. LS6 is best for OEM low rise. But the new LS2 dorman looks like a contender as it has a fast Base and LS2 top, they have been shown to flow more than stock LS2 intakes and close to LS6 without the price tag. I think they come with 90mm openings as well. IF you can go taller like stock truck (mine clears my hood) your TBSS intake is king and the newer TBS truck intakes are better than the originals. Stay away from procomp, better would be the weiland aluminum but you can go full FAST if you got cash to burn.
LS1 spark tables are decent but the truck timing retard is very aggressive, max out all the tq management.
#135
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Re: '88 Formula LM4 5.3 swap
Interesting, I was under the impression that only the L33 (and 4.8s) used the flat top pistons, but since you posted that I went researching and your right! LM4 has flat tops with 10:1 compression.
Definitely want to stick to a car intake, so if I see a good deal on an LS6 manifold, I'll jump on it. But people think they're gold these days.
Definitely want to stick to a car intake, so if I see a good deal on an LS6 manifold, I'll jump on it. But people think they're gold these days.
#136
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Re: '88 Formula LM4 5.3 swap
Yup, only the aluminum 5.3 got flat tops, rated at like 10-15hp more than the normal 5.3.
Yea Ls6 will fetch in the 350-500 range with no rails or injectors. You should check out the dorman versions as they are a hybrid fast design (they own the fast base molds now).
Yea Ls6 will fetch in the 350-500 range with no rails or injectors. You should check out the dorman versions as they are a hybrid fast design (they own the fast base molds now).
#137
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Re: '88 Formula LM4 5.3 swap
This one here? Price is not too bad.
https://www.summitracing.com/parts/rnb-615-900
https://www.summitracing.com/parts/rnb-615-900
#138
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Re: '88 Formula LM4 5.3 swap
Yup. They have small obstructions in the runners. Get a aluminum carbide bit and a high speed drill and 15min u will have them all out and it opens the runners.
Check over on LS1tech, they have a thread on these and I think some Dyno proof.
u can also usually find it cheaper and get summit to price match it. I got the dorman truck intake for $150 vs the $350 they were asking.
Check over on LS1tech, they have a thread on these and I think some Dyno proof.
u can also usually find it cheaper and get summit to price match it. I got the dorman truck intake for $150 vs the $350 they were asking.
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#143
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Re: '88 Formula LM4 5.3 swap
Also, changing the TPS corrected a few quirks about the trans shift points that I was previously blaming on the "truck tune". So I am really happy about that.
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Re: '88 Formula LM4 5.3 swap
I'm surprised you didn't knotice it sooner. Great thing about HP tuners is that I know the TPS voltage and position at all times. I knoticed that my brand new AC delco reads at 0% cold idle and read .4% at warm idle and the voltage reading is slightly tighter when hot vs cold.
make sure your new TPS sensor reads .4-.6v at idle and with the key off and reads 0% TPS position. Once u get above a certain percentage your pcm will not use idle tables and step into the main tables and cause issues.
make sure your new TPS sensor reads .4-.6v at idle and with the key off and reads 0% TPS position. Once u get above a certain percentage your pcm will not use idle tables and step into the main tables and cause issues.
#145
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Re: '88 Formula LM4 5.3 swap
I am sure I would have noticed sooner if I had a chance to get the laptop in the car. Haven't been able to do that since the initial tune to get it started. More tuning will be coming soon and I'll keep the updates coming.
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Re: '88 Formula LM4 5.3 swap
What brand TPS did you go with? I hope it wasn't a generic parts store brand like dorman or anything. I would recommend AC delco and from what I hear they are the most trouble free. AS you already know a wacky TPS sensor reaks all kinds of havock. I had a high idle and fluctuating idle due to TPS voltage going just above idle threshold when hot.
#147
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Re: '88 Formula LM4 5.3 swap
I bought a "standard motor products" TPS from the parts store. Instantly the car has 'felt' better, but I will do like you said and check the idle voltage and key-off voltage when I get the chance.
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Re: '88 Formula LM4 5.3 swap
That should be ok, that would be my 2nd brand to purchase besides Delphi.
Yea .4-.6v but you want to be around .5v with key off and idling. More important is the 0% TPS at warm idle as thats what determines idle to main table transition. Since I run a ported TB, custom cam and ported heads with boost I had to elongate the TPS holes to get me in the .55-.57v range due to cracking the TB blade open to get the IAC counts low.
Yea .4-.6v but you want to be around .5v with key off and idling. More important is the 0% TPS at warm idle as thats what determines idle to main table transition. Since I run a ported TB, custom cam and ported heads with boost I had to elongate the TPS holes to get me in the .55-.57v range due to cracking the TB blade open to get the IAC counts low.
#149
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Re: '88 Formula LM4 5.3 swap
Ah fun, so you had to make it adjustable like an old school TPS.
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Car: 1988 Formula Firebird
Engine: 5.3 LM4
Transmission: 4L65E
Axle/Gears: 3.42 True-Trac
Re: '88 Formula LM4 5.3 swap
Oddly enough, a day after the TPS problem got resolved, my CEL came on again.
Missfire code P0300.
Although it doesn't sound or feel like it's missing. Decided to clear the code but it came back after a few minutes of driving.
Any thoughts? Before I check my plugs and replace wires.
Missfire code P0300.
Although it doesn't sound or feel like it's missing. Decided to clear the code but it came back after a few minutes of driving.
Any thoughts? Before I check my plugs and replace wires.