XE284 Base timing
10-23-2009, 07:13 PM
#1
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Car: 89 Formula 350
Engine: Forged 385 H/C/I
Transmission: 700R4-4300 Stall-lockup
Axle/Gears: BW 9 Bolt 3:70
XE284 Base timing
just wondering what you guys are running for base timing with a comp XE284 cam? I'm running 18* BTDC does that sound about right? This is in a 406 with Brodix 200IK heads...I had it dyno tuned on 8/1/09 and wasnt impressed with the numbers.. to add insult to injury the #4 piston broke just after the tune..This motor only had 50 miles on it.. It looks like the Keith Black Hypertecnic? pistons were not gapped correctly by my builder and broke from the ring up.. Anyway I'm dropping the engine off on monday and prob going with forged pistons this time around..So you guys running the XE284 cam please let me know your base timing! Also let me know what you guys think of this dyno sheet...mods in sig below..thanks
10-23-2009, 08:30 PM
#2
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Re: XE284 Base timing
First off, I'll say that you are brave for trying that cam in a modest EFI engine. It's more than a bit on the big side to work with that intake and it's got a fairly tight LSA to work with EFI.
I think it's likely the reason your chassis dyno numbers are a little lower than you expected. By the time the cam comes to life the intake system is all done. A combination mismatch situation. If I may offer a suggestion, you could probably make more power with that combo on at least 10* less duration.
The KB hypers are very sensitive to top ring gap, but it's more than likely detonation that let to #4s demise. So be aware you might have encountered heavier detonation that you realized. Or a combination of modest detonation and too tight a top ring gap, as you mentioned might be the case.
Timing.... with EFI why are you worried about your base timing? All the magic is in the timing table which is completely tunable against RPM, load, throttle position, etc. Everything is your base timing plus what's in the timing map. 18* initial doesn't mean much without knowing how much the chip is adding at various RPMs, throttle positions, etc.
I think it's likely the reason your chassis dyno numbers are a little lower than you expected. By the time the cam comes to life the intake system is all done. A combination mismatch situation. If I may offer a suggestion, you could probably make more power with that combo on at least 10* less duration.
The KB hypers are very sensitive to top ring gap, but it's more than likely detonation that let to #4s demise. So be aware you might have encountered heavier detonation that you realized. Or a combination of modest detonation and too tight a top ring gap, as you mentioned might be the case.
Timing.... with EFI why are you worried about your base timing? All the magic is in the timing table which is completely tunable against RPM, load, throttle position, etc. Everything is your base timing plus what's in the timing map. 18* initial doesn't mean much without knowing how much the chip is adding at various RPMs, throttle positions, etc.
Last edited by Damon; 10-23-2009 at 08:33 PM.
10-23-2009, 09:39 PM
#3
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Car: 89 Formula 350
Engine: Forged 385 H/C/I
Transmission: 700R4-4300 Stall-lockup
Axle/Gears: BW 9 Bolt 3:70
Re: XE284 Base timing
Well you might be on to something...I was thinking the Super Ram made power to almost 6500RPMs but after doing afew searches it seems to make max power at 5400RPMs. The comp XE284 cam I have in my 406 is advertised to make power from 2300-6500RPMs so it looks like I'll never get to use the top end range of the cam...So I serious considering having the engine made into a roller setup...So does anyone have suggestions on a better cam for my setup???
First off, I'll say that you are brave for trying that cam in a modest EFI engine. It's more than a bit on the big side to work with that intake and it's got a fairly tight LSA to work with EFI.
I think it's likely the reason your chassis dyno numbers are a little lower than you expected. By the time the cam comes to life the intake system is all done. A combination mismatch situation. If I may offer a suggestion, you could probably make more power with that combo on at least 10* less duration.
The KB hypers are very sensitive to top ring gap, but it's more than likely detonation that let to #4s demise. So be aware you might have encountered heavier detonation that you realized. Or a combination of modest detonation and too tight a top ring gap, as you mentioned might be the case.
Timing.... with EFI why are you worried about your base timing? All the magic is in the timing table which is completely tunable against RPM, load, throttle position, etc. Everything is your base timing plus what's in the timing map. 18* initial doesn't mean much without knowing how much the chip is adding at various RPMs, throttle positions, etc.
I think it's likely the reason your chassis dyno numbers are a little lower than you expected. By the time the cam comes to life the intake system is all done. A combination mismatch situation. If I may offer a suggestion, you could probably make more power with that combo on at least 10* less duration.
The KB hypers are very sensitive to top ring gap, but it's more than likely detonation that let to #4s demise. So be aware you might have encountered heavier detonation that you realized. Or a combination of modest detonation and too tight a top ring gap, as you mentioned might be the case.
Timing.... with EFI why are you worried about your base timing? All the magic is in the timing table which is completely tunable against RPM, load, throttle position, etc. Everything is your base timing plus what's in the timing map. 18* initial doesn't mean much without knowing how much the chip is adding at various RPMs, throttle positions, etc.
08-20-2010, 06:29 PM
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Car: 86 IROC-Z, 82 z28
Engine: 383 Stroker
Transmission: TH-350
Axle/Gears: 3.73 Torsen, 4.56 Auburn
Re: XE284 Base timing
I have my xe284 in a 383 stroker and shift at 5500rpm. I run 16* initial advance but the cam really likes it higher, around 20 +/-.
08-22-2010, 12:49 PM
#5
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Re: XE284 Base timing
I run the xe284H and KB hyper pistons in my 406. no problems with the pistons.
I run the timing locked out 34-36deg at idle and max advance. (Carbed)
Your cr is too high and the ring gap was tight. Find another engine builder who has a clue. The xe284H is a poor match to a super ram EFI.
If you want to run a Xe284 cam get a tunnel ram style EFI manifold (stealth ram, ram jet)
or a single plane short runner manifold (Mini ram) or convert a dual plane performer rpm manifold to efi.
If you had flat tops and 64cc head the cr will be too high.
With a 64cc head on a 406 use the -18cc KB174 or the -22cc KB168 pistons. Read the KB directions and set the ring end gaps as recomended.
Find a engine builder who can read.
Then dyno the motor on a real dyno.
For the superram try 226-230 on 112 with a high rocker ratio
I run the timing locked out 34-36deg at idle and max advance. (Carbed)
Your cr is too high and the ring gap was tight. Find another engine builder who has a clue. The xe284H is a poor match to a super ram EFI.
If you want to run a Xe284 cam get a tunnel ram style EFI manifold (stealth ram, ram jet)
or a single plane short runner manifold (Mini ram) or convert a dual plane performer rpm manifold to efi.
If you had flat tops and 64cc head the cr will be too high.
With a 64cc head on a 406 use the -18cc KB174 or the -22cc KB168 pistons. Read the KB directions and set the ring end gaps as recomended.
Find a engine builder who can read.
Then dyno the motor on a real dyno.
For the superram try 226-230 on 112 with a high rocker ratio
Put it on a 383 with 280xfi cam and it made near 470 hp on motor around 5500-5600 rpm 
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