C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Crossfire upgrades

Old 07-11-2018, 09:59 AM
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JIMMIEA42
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Default Crossfire upgrades

thinking about doing some upgrades over the winter to my 84 crossfire with 61,000 miles, looking at doing some porting on the stock intake, roller rockers and air pump delete kit, any advice like should i delete EGR valve, should i go with 1.6 rockers? do not want to mess with the ECM right now except may be a chip for turning on the fan on at lower temp.

Last edited by JIMMIEA42; 07-11-2018 at 10:00 AM.
Old 07-11-2018, 10:31 AM
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Kevova
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Better heads cast or aluminum to bump compression to 10 to 1. Since you're pulling AIR system and intake. Free flow exhaust Used LT1 in a thrifty option.
Old 07-11-2018, 11:10 AM
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84 4+3
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Porting or aftermarket intake gets the biggest gains followed by exhaust and heads. (Not in that order depending) problem is if you port and do heads then the cam is anemic. Port and do exhaust and the heads are a joke etc. A port and exhaust would be the best without having to mess with the ecm.
Old 07-11-2018, 01:00 PM
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billschroeder5842
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Originally Posted by 84 4+3
A port and exhaust would be the best without having to mess with the ecm.
If you get a Renegede intake you will be doing yourself a solid. Then throw no the headers. Frankly I'd leave everything alone at that point as the ECM is limited and if you do TOO much to the engine it will get very confused (air/fuel ratio will be ALL out of spec) with the new pieces.
Old 07-11-2018, 01:04 PM
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JIMMIEA42
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Originally Posted by 84 4+3
Porting or aftermarket intake gets the biggest gains followed by exhaust and heads. (Not in that order depending) problem is if you port and do heads then the cam is anemic. Port and do exhaust and the heads are a joke etc. A port and exhaust would be the best without having to mess with the ecm.
how would on the exhaust side if keeping the exhaust manifold and deleting the catylatic convertor and going duals all the way back with some good mufflers
Old 07-11-2018, 01:12 PM
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JIMMIEA42
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Originally Posted by billschroeder5842
If you get a Renegede intake you will be doing yourself a solid. Then throw no the headers. Frankly I'd leave everything alone at that point as the ECM is limited and if you do TOO much to the engine it will get very confused (air/fuel ratio will be ALL out of spec) with the new pieces.
what would you do with the exhaust after headers
Old 07-11-2018, 01:37 PM
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If you go 1.6 replace your springs, be prepared to spend some time on that intake! Headers are a plus...I wouldnt bother eliminating smog stuff it doesnt hurt anything.
plenty of guys here have some strong runing CFI they can pipe in with their tips.
Old 07-11-2018, 01:38 PM
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84 4+3
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Originally Posted by JIMMIEA42
how would on the exhaust side if keeping the exhaust manifold and deleting the catylatic convertor and going duals all the way back with some good mufflers
IIRC the manifolds are the worst part. If you do headers I know a few members went with the full system from Melrose and are very happy with them. That being said making it true dual with an x-pipe would probably help some.
Old 07-11-2018, 01:44 PM
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Tom400CFI
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EGR won't make any diff, on or off. EGR doesn't function at high throttle so it's not hurting power.


Originally Posted by Kevova
Free flow exhaust Used LT1 in a thrifty option.



Originally Posted by 84 4+3
A port and exhaust would be the best without having to mess with the ecm.



Originally Posted by JIMMIEA42
what would you do with the exhaust after headers
Full dual exhaust.

Old 07-11-2018, 02:05 PM
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billschroeder5842
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Originally Posted by 84 4+3
A port and exhaust would be the best without having to mess with the ecm.
If you get a Renegede intake you will be doing yourself a solid. Then throw the headers and a nice exhaust. Frankly I'd leave everything alone at that point as the ECM is limited and if you do TOO much (heads, cam, etc) to the engine it will get very confused (air/fuel ratio will be ALL out of spec) with the new pieces.

Last edited by billschroeder5842; 07-11-2018 at 02:06 PM.
Old 07-11-2018, 03:03 PM
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Great info. here

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Old 07-11-2018, 03:10 PM
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Hot Rod Roy
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Whether you decide to port your stock intake, or swap to the Renegade manifold, I'd suggest a trim to the "swirl plates" on the bottom of the throttle bodies. Don't remove them. They improve the fuel distribution in the plenum.

Before:


After:


This can be done without removing the swirl plates or the throttle bodies from the top plate.

If you want to have your radiator fan come on at a lower temp, install an ACDelco D1855B sensor. That sensor is in the RH head, between plugs 6 & 8. (This is the CTS location for the '84 only!)

Old 07-11-2018, 03:17 PM
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Originally Posted by Hot Rod Roy
Whether you decide to port your stock intake, or swap to the Renegade manifold, I'd suggest a trim to the "swirl plates" on the bottom of the throttle bodies. Don't remove them. They improve the fuel distribution in the plenum.

Before:


After:


This can be done without removing the swirl plates or the throttle bodies from the top plate.

If you want to have your radiator fan come on at a lower temp, install an ACDelco D1855B sensor. That sensor is in the RH head, between plugs 6 & 8. (This is the CTS location for the '84 only!)

What temp will it come on at ? the guy before me put a 170 thermostat in and it does not get over 185 and the overdrive does not kick in is what he said, i just got the car and have really only drove short distances, i am going to put a 190 thermostat back in it and service the overdrive unit and chage trans fluid
Old 07-12-2018, 06:51 PM
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zachaeous
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If it were mine I would port the stock intake and then port it some more. I did this to my current 84. I went with dual exhaust all the way back. I also replaced the camshaft with the old GM 327-350 hp grind: The engine was a complete rebuild with a .030 oversize bore. I also changed the fan thermostat and the water thermostat to 180 degree. I also installed a 2500 stall torque converter when rebuilding the transmission.327 350 hp camshaft specs. CS-179R Sealed Power brand.

Cam Style: Hydraulic flat tappet

Basic Operating RPM Range: 2,200-5,200

Intake Duration at 050 inch Lift: 222

Exhaust Duration at 050 inch Lift: 222 Duration at 050 inch Lift: 222 int./222 exh. Advertised Intake Duration: 290

Advertised Exhaust Duration: 290

Advertised Duration: 290 int./290 exh. Intake Valve Lift with Factory Rocker Arm Ratio: 0.447 in.Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.447 in.Valve Lift with Factory Rocker Arm Ratio: 0.447 int./0.447 exh. Lobe Separation (degrees): 114

I really spent a lot of time porting the stock intake. I took my direction from forum members that gave me advice and the information that is on the cube studio website. I also re-bushed the throttle body shafts with a bronze self-lubricating bushings. I put a fuel line with a gauge in it between the two throttle bodies. I replaced the old fuel pump with a new pump and I have 14psi of fuel pressure. A renegade intake is a great item and a easy bolt on. IIRC I think I spent about 50.00 on tools and materials (including re-bushing the throttle bodies) to port the stock intake and my time.

What you do will improve the performance of your 84. I had a brand new 84 and the difference is definitely there. Good luck with your mods.
Old 07-12-2018, 07:00 PM
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84 4+3
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Originally Posted by zachaeous
If it were mine I would port the stock intake and then port it some more. I did this to my current 84. I went with dual exhaust all the way back. I also replaced the camshaft with the old GM 327-350 hp grind: The engine was a complete rebuild with a .030 oversize bore. I also changed the fan thermostat and the water thermostat to 180 degree. I also installed a 2500 stall torque converter when rebuilding the transmission.327 350 hp camshaft specs. CS-179R Sealed Power brand.

Cam Style: Hydraulic flat tappet

Basic Operating RPM Range: 2,200-5,200

Intake Duration at 050 inch Lift: 222

Exhaust Duration at 050 inch Lift: 222 Duration at 050 inch Lift: 222 int./222 exh. Advertised Intake Duration: 290

Advertised Exhaust Duration: 290

Advertised Duration: 290 int./290 exh. Intake Valve Lift with Factory Rocker Arm Ratio: 0.447 in.Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.447 in.Valve Lift with Factory Rocker Arm Ratio: 0.447 int./0.447 exh. Lobe Separation (degrees): 114

I really spent a lot of time porting the stock intake. I took my direction from forum members that gave me advice and the information that is on the cube studio website. I also re-bushed the throttle body shafts with a bronze self-lubricating bushings. I put a fuel line with a gauge in it between the two throttle bodies. I replaced the old fuel pump with a new pump and I have 14psi of fuel pressure. A renegade intake is a great item and a easy bolt on. IIRC I think I spent about 50.00 on tools and materials (including re-bushing the throttle bodies) to port the stock intake and my time.

What you do will improve the performance of your 84. I had a brand new 84 and the difference is definitely there. Good luck with your mods.
How do you like that cam with the crossfire?
Old 07-12-2018, 07:27 PM
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Quote: How do you like that cam with the crossfire?

It woke the engine up. Along with everything else I did it made the car a completely different experience to drive. The only downfall is the idle. I have tried the stock idle RPM but it does not want to idle properly until 650 RPM in drive. I balanced the throttle bodies after getting it fired up and setting the idle.
Old 07-13-2018, 12:11 AM
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Originally Posted by zachaeous
Quote: How do you like that cam with the crossfire?

It woke the engine up. Along with everything else I did it made the car a completely different experience to drive. The only downfall is the idle. I have tried the stock idle RPM but it does not want to idle properly until 650 RPM in drive. I balanced the throttle bodies after getting it fired up and setting the idle.
You happen to have dyno numbers? If you posted them and I missed them I'm sorry... I'm on fumes right now.

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Old 07-13-2018, 11:44 AM
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Originally Posted by Hot Rod Roy
I'd suggest a trim to the "swirl plates" on the bottom of the throttle bodies. Don't remove them. They improve the fuel distribution in the plenum.
FYI, I totally removed my swirl plates, and radiused the underside/outlet of the TB's like a reverse velocity stack. My distribution, going by plug reads, was as good as with the stock set up. Driveability and fuel economy were unaffected.
Old 07-13-2018, 01:01 PM
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cardo0
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You need to check your local smog requirements before modifying to true duals. That could become an expensive experiment.

To actually verify fuel distribution on any induction system you would need thermalcouples on each exhaust tube to monitor temperatures. Visually checking the spark plugs could only detect gross distribution problems. Some say they can do this with an hand held IR gun - I'm not a believer of that either.
Old 07-13-2018, 01:23 PM
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Originally Posted by cardo0
You need to check your local smog requirements before modifying to true duals. That could become an expensive experiment.

To actually verify fuel distribution on any induction system you would need thermalcouples on each exhaust tube to monitor temperatures. Visually checking the spark plugs could only detect gross distribution problems. Some say they can do this with an hand held IR gun - I'm not a believer of that either.
i live in Minnesota so no smog here

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