Q: Please educate me about camshafts for a 3.8 N/A engine...
After finding that my suspension and brake setup is pretty well dialed in for my target purpose (24 Hours of Lemons track car), my next plan is to increase the HP beyond its original setup using whatever residual money they give me.
Right now, my configuration is as follows:
* 95 Thunderbird chassis
* 3.73:1 rear gears.
* 205/50R15 tires. Yes it looks retarded but the tires are sticky and wear quite well. Effective gear ratio due to the smaller tires and rear gears -- 4.3:1.
* M5R2 transmission from an 89SC
* Stock 93 ECU. We are using the 95's MAF but the car doesn't seem to have any issues using it (different part number).
* Governor issue solved with a 23 tooth speedometer gear. We can go plenty fast (eventually) given the speed.
* Exhaust is stock 49-state (manifolds, 3 cats but with a cherry bomb at the end). According to the last smog report, the cats were NOT clogged at all.
* Gearing is very, very short. First until the car starts rolling, 2nd for not much longer than that. At Infineon, we pretty much used 3-4-5 gear anyway so this isn't a problem.
* Annoyance: with the car in gear and your foot off the gas, I believe the car is leaning out and throws a code about the fuel system cutting out (542 -- Fuel pump circuit open). I believe this is caused by the ECU actually being for an auto and not understanding why the engine is still revving but the throttle is NOT being depressed. It doesn't affect the drivability of the car so I could care less.
* Annoyance: 2nd gear synchro is gone. Oh well.
* Problem: Car does NOT rev beyond 4K under load. Now that we have a manual, I can conclusively say this is a problem with the engine and NOT the transmission.
Proposed Solution & Questions
1) Splitport Upgrade: I have the heads, intake manifolds, and understand the fuel rail mods required (or at least, I think I do).
I understand that the concept of IMRCs is to open up the short runners @ high RPM and the longer ones at low RPM to increase air speed and improve torque.
Q: For my application (road track racing) and given my car's current config (i.e.: already pretty short gears), do I even need to bother with retrofitting an RPM activated switch or should i pop out the butterflies?
2) Given my lemony budget limitations, I will probably stick with the current 93 ECU. I understand that while I won't gain the most HP from my mods, it will still work. Of course, if the leaning out becomes excessive thanks to the more free flowing intake, I'll suck it up and get a chip.
3) Since I have the time, I plan to DIY polish the intake and possibly port match the upper/lower intake. Full porting seems excessive and I run the chance of grinding away too much metal between the runners. While I plan to have the heads resurfaced, the intake will either go on AS-IS or polished (noone is going to professionally port it for me).
Q: Will this help me any given my engines planned config? Will it hurt (perhaps reduce swirl)?
4) Other parts needed:
Q: I also need new bolts, don't I? Is ARP the brand to buy or is there something more budget friendly I should consider? I see that rockauto has some Felpro ones for $12.xx. Remember, this is a lemons car, not a daily driver.
Q: Gasket kits - considering I'm not planning to make crazy power (I'll be happy with just over 200HP), can I get away with a Felpro kit or Corteco or do I need something like an MLS gasket.
5) Finally, please educate me on camshafts.
Q: This 3.8L N/A engine comes with hydraulic rollers as stock, right?
Q: Is this my stock camshaft spec?
Part # E9SZ-6250-B
185/193 intake/exhaust dur @ .050"
.423/.445 int/exh lift
112 lca and 109 IC
Q: If I don't trust my existing engine's camshaft, what camshaft should I consider? Should I also get replacement springs as well or re-use the ones I currently have?
I don't have another race I'm planning to enter just yet so your advice/feedback will give me ideas on how to work on this project gradually.
The chassis has 130K on the odometer and I know the engine I have has been re-manufactured but your guess is as good as mine as to if the current engine is even close to OEM spec. My goal is to keep with the lemony theme for this engine rebuild/upgrade so you won't see me trying to blueprint this engine or going absolutely nuts with the internals.
While I do have an 89 SC engine block from my donor car, I think I'll be better served converting it into a "drop in" spare vs. building it up.
Thanks in advance for your replies.
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Last edited by S4gunn; 03-27-2012 at 04:28 PM.