poor dyno numbers from 408 :( - Page 2

7DMACH1 · 04-14-2005, 11:56 AM

I looked at your build sheet. The xe284h cam is part number 31-250-4. Comp Cams site says any cam with a 31 prefix uses the old firing order 1-5-4-2-6-3-7-8. If you are useing 1-3-7-2-6-5-4-8 this is your problem. I've seen it before.

rwhite65 · 04-14-2005, 05:58 PM

Andy669- I am thinking he would benefit most from a custom cam, which I think he will have no problems with purchasing. Even though it is a shelf cam, I really think this thing should be able to run decent with that cam. I also found the specs on the Edelbrock valve springs and can post them if they would help at all.

7DMach1- I checked the firing order and it was where "I" thought it should be. I looked all over Comp cams website and can not find where it talks about the proper firing order. Where did you find that? I can not remember what firing order I went with, so now I got to take a look at my notes if I can find them.

thanks,
Ryan

Ieatcamaros · 04-14-2005, 09:32 PM

Quote:

Originally Posted by 7DMACH1

I looked at your build sheet. The xe284h cam is part number 31-250-4. Comp Cams site says any cam with a 31 prefix uses the old firing order 1-5-4-2-6-3-7-8. If you are useing 1-3-7-2-6-5-4-8 this is your problem. I've seen it before.

I'll second that. A representative at Comp cams told me this very thing. Prefix 31 is the old 302 firing order and Prefix 35 is the 351W and HO 302 firing order.

7DMACH1 · 04-14-2005, 11:07 PM

Here's where I found it. Ray
http://www.compcams.com/Technical/Cu...HTML/62-65.asp

rwhite65 · 04-15-2005, 12:25 AM

I appreciate the help, but the cam card I have has a 35 prefix, so as I understand the replies that would mean I need the late style firing order??
Ryan

andy669 · 04-15-2005, 07:02 AM

If the firing order was wrong, you would hear it. Plus, if that thing made 300 horses on only 4 cylinders? Holy shit! That thing would be a monster. 1-2-6-8 will still fire correctly either way. Good thought, but I dont think thats the problem.

It could very well be something timing related. 15 degrees of timing was worth exactly 100 horsepower in my car.

Andy

rwhite65 · 04-15-2005, 09:19 AM

I really think it is going to be the timing. I have just gotten busy with work here (begining of my work week) and have not had time to put the advancement pieces back in.

I am hoping tomorrow to put it together correctly, which should give me atleast 20 more degrees total advancement (give or take a few). Will post when we do it.
Ryan

andy669 · 04-17-2005, 07:33 PM

Heres a couple of my dyno pulls.

Andy

rwhite65 · 04-17-2005, 08:29 PM

Andy669,
thanks for posting that....gonna be a few days before the car can do a pull again......see the other post.

Ryan

rwhite65 · 05-08-2005, 03:28 PM

Well, the thing feels tons better since we have played with timing and fixed the broken timing chain cover

The big rear tires dont seem big at all on this car.

I think a dyno is gonna show it is falling sooner then it should. Around 5,000 5,500 she still falls off. I believe the cam is designed to pull to 6,500. I am kinda thinking the high volume carter fuel pump (mechanical) may not be able to keep up at the higher rpms. Any thoughts?
Ryan

rwhite65 · 05-10-2005, 12:18 PM

I may have found another problem. The car looks to still have 2.25 exhaust on it. I dont see how the thing could be breathing thru that with its cubes.
Ryan

Dark_5.0 · 05-10-2005, 02:40 PM

I would imagine a 408 would be pretty choked breathing through 2 1/4. Its time for 3 inch.

tarmon8r · 05-12-2005, 09:18 PM

Im not thinking that edelbrock performer head is gonna flow enough for 408 ci 6500 rpm pulls. Exhaust needs upgrading as well.

04-14-2005, 11:56 AM	#21
7DMACH1 Registered Member Join Date: Nov 2001 Location: PHILA. PA USA Posts: 469	Re: poor dyno numbers from 408 :( I looked at your build sheet. The xe284h cam is part number 31-250-4. Comp Cams site says any cam with a 31 prefix uses the old firing order 1-5-4-2-6-3-7-8. If you are useing 1-3-7-2-6-5-4-8 this is your problem. I've seen it before.

04-14-2005, 05:58 PM	#22
rwhite65 Ride Hard Join Date: Oct 2000 Location: Wyoming IL Posts: 1,094	Re: poor dyno numbers from 408 :( Andy669- I am thinking he would benefit most from a custom cam, which I think he will have no problems with purchasing. Even though it is a shelf cam, I really think this thing should be able to run decent with that cam. I also found the specs on the Edelbrock valve springs and can post them if they would help at all. 7DMach1- I checked the firing order and it was where "I" thought it should be. I looked all over Comp cams website and can not find where it talks about the proper firing order. Where did you find that? I can not remember what firing order I went with, so now I got to take a look at my notes if I can find them. thanks, Ryan __________________ 65 Fastback 91 roller 306, H/C/I AOD-Bauman, PI Stallion, 4.10's and traction loc 04 Grand Cherokee Freedom Edition 79 Ford F-250 4x4 - Restored

04-14-2005, 11:07 PM	#24
7DMACH1 Registered Member Join Date: Nov 2001 Location: PHILA. PA USA Posts: 469	Re: poor dyno numbers from 408 :( Here's where I found it. Ray http://www.compcams.com/Technical/Cu...HTML/62-65.asp

04-15-2005, 12:25 AM	#25
rwhite65 Ride Hard Join Date: Oct 2000 Location: Wyoming IL Posts: 1,094	Re: poor dyno numbers from 408 :( I appreciate the help, but the cam card I have has a 35 prefix, so as I understand the replies that would mean I need the late style firing order?? Ryan __________________ 65 Fastback 91 roller 306, H/C/I AOD-Bauman, PI Stallion, 4.10's and traction loc 04 Grand Cherokee Freedom Edition 79 Ford F-250 4x4 - Restored

04-15-2005, 07:02 AM	#26
andy669 Registered Member Join Date: Jan 2001 Location: Moline Il Posts: 901	Re: poor dyno numbers from 408 :( If the firing order was wrong, you would hear it. Plus, if that thing made 300 horses on only 4 cylinders? Holy shit! That thing would be a monster. 1-2-6-8 will still fire correctly either way. Good thought, but I dont think thats the problem. It could very well be something timing related. 15 degrees of timing was worth exactly 100 horsepower in my car. Andy __________________ 88 coupe 91 LX NMRA Pure Street 5120

04-15-2005, 09:19 AM	#27
rwhite65 Ride Hard Join Date: Oct 2000 Location: Wyoming IL Posts: 1,094	Re: poor dyno numbers from 408 :( I really think it is going to be the timing. I have just gotten busy with work here (begining of my work week) and have not had time to put the advancement pieces back in. I am hoping tomorrow to put it together correctly, which should give me atleast 20 more degrees total advancement (give or take a few). Will post when we do it. Ryan __________________ 65 Fastback 91 roller 306, H/C/I AOD-Bauman, PI Stallion, 4.10's and traction loc 04 Grand Cherokee Freedom Edition 79 Ford F-250 4x4 - Restored

04-17-2005, 08:29 PM	#29
rwhite65 Ride Hard Join Date: Oct 2000 Location: Wyoming IL Posts: 1,094	Re: poor dyno numbers from 408 :( Andy669, thanks for posting that....gonna be a few days before the car can do a pull again......see the other post. Ryan __________________ 65 Fastback 91 roller 306, H/C/I AOD-Bauman, PI Stallion, 4.10's and traction loc 04 Grand Cherokee Freedom Edition 79 Ford F-250 4x4 - Restored

05-08-2005, 03:28 PM	#30
rwhite65 Ride Hard Join Date: Oct 2000 Location: Wyoming IL Posts: 1,094	Re: poor dyno numbers from 408 :( Well, the thing feels tons better since we have played with timing and fixed the broken timing chain cover The big rear tires dont seem big at all on this car. I think a dyno is gonna show it is falling sooner then it should. Around 5,000 5,500 she still falls off. I believe the cam is designed to pull to 6,500. I am kinda thinking the high volume carter fuel pump (mechanical) may not be able to keep up at the higher rpms. Any thoughts? Ryan __________________ 65 Fastback 91 roller 306, H/C/I AOD-Bauman, PI Stallion, 4.10's and traction loc 04 Grand Cherokee Freedom Edition 79 Ford F-250 4x4 - Restored

05-10-2005, 12:18 PM	#31
rwhite65 Ride Hard Join Date: Oct 2000 Location: Wyoming IL Posts: 1,094	Re: poor dyno numbers from 408 :( I may have found another problem. The car looks to still have 2.25 exhaust on it. I dont see how the thing could be breathing thru that with its cubes. Ryan __________________ 65 Fastback 91 roller 306, H/C/I AOD-Bauman, PI Stallion, 4.10's and traction loc 04 Grand Cherokee Freedom Edition 79 Ford F-250 4x4 - Restored

05-10-2005, 02:40 PM	#32
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	Re: poor dyno numbers from 408 :( I would imagine a 408 would be pretty choked breathing through 2 1/4. Its time for 3 inch. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

05-12-2005, 09:18 PM	#33
tarmon8r Registered Member Join Date: Jun 2002 Location: manassas, va Posts: 186	Re: poor dyno numbers from 408 :( Im not thinking that edelbrock performer head is gonna flow enough for 408 ci 6500 rpm pulls. Exhaust needs upgrading as well. __________________ 1983 mustang, 393 cubic inch stroker small block, victor jr heads and intake, gold race 1.6 roller rockers. comp cam 304, 244@ .050. .576" hydralic retro roller cam,lunati rods. block was o-ringed,10:1 forged pistons, speed pro fit fit rings, clevite bearings,msd distributor and igniton,be cool huge radiator, black lite electric fan, march underdrive pulleys, mildon deep sump oil pan, mac 1 3.4" long tube headers, 3" dr gas x-pipe and mac exhaust,ARP bolts. car weighs 2900 lbs w/out driver, sub frames, weld wheels, mickey thompson sportsman pro 26 x 10.5 x 15's,#8 fuel line steel braided

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