speed density

sheilaspony · 08-14-2005, 07:59 AM

ok almost finished with new motor for 86 gt.forged flat tops X303 cam gt 40s stainless valves.wanna run the speed density.ran out of money lol.what are the problems im gonna run into?have wet shot nitrous.can i change injectors?throttle plate? please help thx

tmoss · 08-14-2005, 09:56 AM

The problem you will have is with idle if you can't maintain enough vacuum to keep the EEC from seeing the motor as "under load". The SD EEC uses vacuum to the MAP to judge when the motor is accelerating (under load) and lower than factory vacuum readings make it give too much fuel at ilde.

Rhoads now makes roller lifters that might help the idle out a lot. They are a variable duration lifter. They have a patented machined groove in the lifter plunger that bleeds off oil/duration at lower cam speeds. The bleed off rate is not enough to affect duration as cam speed increases. I ran the flat tappet version of them years ago in my 67 Camaro 383 to take a Comp Cam's 292 idle.

skiwesser · 08-23-2005, 01:26 AM

88 WORKCAR went a long way with mods w/ S.D., I'd ask him but if you change injectors it'll supply fuel to what it thinks are 19#er's, seems to me that would cause problems? T.B no problem, Wet system ok if you got enough fuel pump.

08-14-2005, 07:59 AM	#1
sheilaspony Registered Member Join Date: May 2005 Posts: 6	speed density ok almost finished with new motor for 86 gt.forged flat tops X303 cam gt 40s stainless valves.wanna run the speed density.ran out of money lol.what are the problems im gonna run into?have wet shot nitrous.can i change injectors?throttle plate? please help thx

08-14-2005, 09:56 AM	#2
tmoss Registered Member Join Date: Mar 2003 Location: Saint Louis, MO Posts: 634	Re: speed density The problem you will have is with idle if you can't maintain enough vacuum to keep the EEC from seeing the motor as "under load". The SD EEC uses vacuum to the MAP to judge when the motor is accelerating (under load) and lower than factory vacuum readings make it give too much fuel at ilde. Rhoads now makes roller lifters that might help the idle out a lot. They are a variable duration lifter. They have a patented machined groove in the lifter plunger that bleeds off oil/duration at lower cam speeds. The bleed off rate is not enough to affect duration as cam speed increases. I ran the flat tappet version of them years ago in my 67 Camaro 383 to take a Comp Cam's 292 idle. __________________ Tom (Torque) Moss 88Gt 5spd Vert, FLowmaster Catbacks, stock cam advanced 4° @ 108.5° ICL, NMRA prepped GT40P heads 1.85/1.55 valves and 1.7 rockers, MAC P headers Jet-Hot coated, 97 Exlporer intake (ported lower), TB and injectors. 277RWHP/330RWTQ (SAE). http://www.fastlanecars.com/

08-23-2005, 01:26 AM	#3
skiwesser Registered Member Join Date: Sep 2000 Location: rock hill,S.C. 29730 Posts: 420	Re: speed density 88 WORKCAR went a long way with mods w/ S.D., I'd ask him but if you change injectors it'll supply fuel to what it thinks are 19#er's, seems to me that would cause problems? T.B no problem, Wet system ok if you got enough fuel pump. __________________ 88 GT: subs,pullies, 1 3/4 longtubes, flowmasters, AFR 165's,T,F #1 cam,Thyphoon intake, 24# inj., 73mm C&L,65mmT.B., 190LPH pump, Eagle sir rods, forged pistons in a newly rebuilt 306. DYNO TUNED TO 300.97 RWHP 337RWTQ

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