| Author |
Message |
    
under power
| | Posted on Monday, January 20, 2003 - 09:54 pm: | 
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would like to squeeze more hp from a 3.9 efi and was woundering on any suggestions. i was thinking about advancing the timing, or platnum plugs... im on limited budget and would like to keep it simple! |
trevor griffiths (Trevorgriffiths)
| | Posted on Monday, January 20, 2003 - 11:00 pm: |
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I heard that a 4.2 chip will fit in the 3.9 computer. A 3.9 engine was rated at 188hp and the 4.2 at 200. The cam and displacement make up some of the hp bump, so the chip must be worth several hp. I don't have the p/n, but I understand it's less than $50! I am also going to try shortening the velocity stacks in the intake. The original set-up doesn't leave much room for airflow at large throttle openings.
I would also check the vacuum advance on the distributor-easily 5% in mileage and horsepower if it is not working properly.
I am currently building my engine into a 4.6 with the Piper RP4 cam, the 4.2 chip, and the stack mods. I had a seeping headgasket and after the heads were off, I just couldn't stop myself. Good thing,too, after 150k, the cam was worn out and a few bearings wouldn't have made it much longer, anyway! |
Paul Schuetz (Schuetz)
| | Posted on Tuesday, January 21, 2003 - 01:09 am: |
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I did the full Jacobs ignition kit, Borla Cat Back, and the K&N air filter. Noticed a considerable horsepower increase.
Paul |
TPH (Snowman)
| | Posted on Tuesday, January 21, 2003 - 07:40 am: |
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Paul-
Where did you buy the ignition kit and how was the installtion? Thanks.
S- |
Ali
| | Posted on Tuesday, January 21, 2003 - 10:28 am: |
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Trevor,
Can you email me?
Thanks. |
John Cinquegrana (Johnc)
| | Posted on Tuesday, January 21, 2003 - 11:05 am: |
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Check with AdrianS, he installed some Janspeed headers and it's improved his performance ('91 3.9)... |
wesenheimer
| | Posted on Tuesday, January 21, 2003 - 03:03 pm: |
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Trevor,
If you're turning your 3.9 into a 4.6, are you using a 4.6 short block and using the 3.9 heads?
Why use a 4.2 chip for a 4.6? Maybe it will work, but sounds wrong. With the extra displacement of the 4.6, are you sure the 4.2 chip will read all the engine perameters correctly?
Did Chris at RPi say it would work?
Sorry to be a "quizling", but just curious
weisenheimer |
John Cinquegrana (Johnc)
| | Posted on Tuesday, January 21, 2003 - 03:07 pm: |
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I heard from Eric (AB, 88 RR with 4.6) that you need to use the 4.2 ECU. Now, I will be using a 4.6 long block and his answer was based on this. I don't know if it would be different if you are going from a 3.9 to a 4.6.... |
weisen.....
| | Posted on Tuesday, January 21, 2003 - 03:38 pm: |
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John,
So he (Eric) is saying he 4.2chip will support a 4.6? |
John Cinquegrana (Johnc)
| | Posted on Tuesday, January 21, 2003 - 03:43 pm: |
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Yep...that's what he has in his RR with a 4.6 engine. |
trevor griffiths (Trevorgriffiths)
| | Posted on Wednesday, January 22, 2003 - 11:08 am: |
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I am using the 4.6 short block and the 3.9 heads and a RP4 cam. The 4.6 computer is OBDII with a lot more stuff than a pre-96 engine has. 4 o2 sensors vs. 2 etc. The 4.2 chip will allow more fuelling for the increased displacement, while still allowing me to use the original fuel injectors, intake manifold and other engine sensors. I suppose a 4.6 engine harness and ecu could be fitted, but I would envision a considerable investment for only small gains.
I should have the engine back next week and maybe in the Rover by the end of the month. Rovertym is fabricating a rear bumper for the Disco I , so I don't even have the truck at my shop. |
trevor griffiths (Trevorgriffiths)
| | Posted on Wednesday, January 22, 2003 - 12:39 pm: |
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Ali,
I tried to e-mail, but it was returned. You can e-mail me at [email protected] |
Ali
| | Posted on Wednesday, January 22, 2003 - 02:09 pm: |
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Trevor,
You've got mail. |
Ali
| | Posted on Wednesday, January 22, 2003 - 02:12 pm: |
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I'd love to hear some thoughts from Eric on this matter as well. Eric, where are you buddy? |
Brian Stolpa (87hprover)
| | Posted on Thursday, February 06, 2003 - 09:18 pm: |
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I have an 87 use to be 3.5 but now has 2002 series two engine in it, with custom ground engle cam and cloyes true dual roller timing chain advanced 4 degrees, MSD distibutor, 6offroad ignition box, and blaster coil, portmatched intake, hedman longtube ceramic coated headers, true dual exhaust with high flow catco cats and 70 series flowmaster, all estimated on dyno program about 235 horse and 280 torque, right now I think that's it. I have 33's on it and never changed gears this thing has so much torque I don't need to at this point, it has awesome pulling power |
Charles A. Neal (Cneal)
| | Posted on Friday, February 07, 2003 - 12:23 pm: |
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I just upgraded my exhuast with a MagnaFlow Performance system. It seems to have increased HP a bit, atleast I can now go up the canyon at 55 mph instead of 50. I also increased my gas mileage by about 1.5/gal.
cneal. |
Leslie N. Bright (Leslie)
| | Posted on Friday, February 07, 2003 - 12:32 pm: |
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The way I see it, the 4.6 is set up as being distributorless, whereas the 3.9 and 4.2 have a distributor. As Trevor said, the OBD-II has a lot of other extra stuff...
If you're starting w/ a 3.9 vehicle, even though you've got the 4.6 block now the 4.2 chip would let you keep the factory wiring setup....
At least that's what makes sense to me....
-L |
Michael Slade
Unregistered guest
| | Posted on Tuesday, February 11, 2003 - 12:34 pm: |
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Pull the 3.9 and put in a 350! Hehe.
BTDT....
Michael |
Prescottj (Prescottj)
Advanced member
Username: Prescottj
Post Number: 142
Registered: 12-2002
| | Posted on Wednesday, February 12, 2003 - 12:24 pm: |
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ebay has a chip for about 5 bucks that adds 10-20 hp.
lol don't get scammed like the last guy that bought one for his Disco |
me and my questions
Unregistered guest
| | Posted on Saturday, February 15, 2003 - 07:49 am: |
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how would i get more horse power from a 350 chev if i fitted it. where do you get the adapter plate.
five dollars and a 20 horse power increase sounds like horse shit? |
Prescottj (Prescottj)
Member
Username: Prescottj
Post Number: 168
Registered: 12-2002
| | Posted on Sunday, February 16, 2003 - 03:30 pm: |
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it is they sell a 25 cent resistor from radio shaq and charge you 5 bucks |
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