Mass air vs Speed density

[Masshole]

the engine that was in my old Notch was origanally dyno'd in a 88 GT with speed density and a stock drivetrain. but i had mass air and a heavily modified drvivetrain.... would the dyno numbers be different if the engine was dyno'd in my Notch??

[speedfreak87]

probabyly be a little different.. but it also depends on what the guy before you did to his computer to get the mods to work with SD.

[Masshole]

probabyly be a little different.. but it also depends on what the guy before you did to his computer to get the mods to work with SD.

computer was stock when the engine was dyno'd. and we upgraded with a chip from superchips.

[speedfreak87]

stock SD computer with an F-303 cam? and it ran? that don't sound right.. SD despise anything bigger then a stock cam.. some thhing had to of been done to make that car run off of SD.

[Masshole]

stock SD computer with an F-303 cam? and it ran? that don't sound right.. SD despise anything bigger then a stock cam.. some thhing had to of been done to make that car run off of SD.

well thats wat i was told. and it use 2 run like s**t thats why the kid sold the engine. his car use 2 stall out... idle would be all over the place... fuel would seem to cut out while under accelartaion.

thats why i asked if the numbers would be different. the HP and TRQ numbers seemed weird to me for an F cam... but i seen the dyno sheet tho.

[speedfreak87]

well thats wat i was told. and it use 2 run like s**t thats why the kid sold the engine. his car use 2 stall out... idle would be all over the place... fuel would seem to cut out while under accelartaion.

thats why i asked if the numbers would be different. the HP and TRQ numbers seemed weird to me for an F cam... but i seen the dyno sheet tho.


SD doesn't like mods at all.. especially cams.. so yeah it will run like shit if it was a stock computer.. it's cheaper to convert to mass air, vs tune a SD car.

[Masshole]

SD doesn't like mods at all.. especially cams.. so yeah it will run like shit if it was a stock computer.. it's cheaper to convert to mass air, vs tune a SD car.

it was a $14k we got for $9700. so i guess my numbers would have been higher. which dont make me feel any better... just means i was a shitty driver :lmao1:

[foureyedcoupe]

You can mod a SD car. The only mod that generally causes issues is when you change the camshaft. But there are ways around that also, if you keep the lobe center tight and keep the duration close to stock. The trick is to try and keep the engine producing somewhere around 19inches of vacuum. But it is easier just to switch to mass air, which is more forgiving.

[Masshole]

You can mod a SD car. The only mod that generally causes issues is when you change the camshaft. But there are ways around that also, if you keep the lobe center tight and keep the duration close to stock. The trick is to try and keep the engine producing somewhere around 19inches of vacuum. But it is easier just to switch to mass air, which is more forgiving.

19inches of wat??? hey idk wat ur talkin bout... all i did was say.. " hey i want that.. that.. this and that too". :lol: and then turned wrenches :mick:

[speedfreak87]

The bigger the cam the less vacume (if I have that right) SD is very senistive.. cams bigger then stock it will not agree with.. for the most part with a SD car you can put heads and an intake it might still run "ok" put a bigger cam in it, you're looking for trouble.. it can be done, just more cost efficient to convert to mass air.

I had an 87, I had an entire cobra conversion ready to go in, mass air (conversion harness) , intake, injectors everything.. I'm putting an e-cammed 306 with (massivly)ported gt-40p heads.. there was no way I could put that on a SD with out the conversion.. since the demise of my beloved 87, I now have my current headache, wich is getting the same motor only with a carb, and a direct port fogger system. I say it blows up first pass but we'll see.

[Masshole]

well thats why the first thing we did was convert 2 mass air. but my problem with everything was i was still runnin WAY to rich. was gettin like 9mph in the city. this thing would backfire like there where firecrackers in the exhaust or sumthing sick like that.

so i guess my question for the most part was answered. but wat i never got... is it was afully balanced and blue-printed DSS 331 stoker, stage 2 TFS head, F-303 and a stage3 cobra intake... now how do u only make 362HP but nake 439TRQ?? i would normally think the TRQ numbers wouldnt be that high with an Fcam tho. so i wonder it havin SD at first threw off the numbers then?

well ill never kno now. lol


and im not a fan convertin 2 carb in a car that wasnt carb b4 hand. i gues that why i prefer the 86 over the 85 :lol:

[speedfreak87]

well, DSS is know for a few bad motors here and there.. check the boards.. alot of complaints about them.. but, the fuel mileage doesn't sound right that's for sure.. if it was tuned right you should have had decent fuel mileage..

My current headache is an 81 coupe. originally carbed.. I should have just converted it to FI like I was planning to but I listen to my buddy.. had I went with MY plan the car would be running right now for the most part.. it's almost there.. almost..

[Masshole]

well, DSS is know for a few bad motors here and there.. check the boards.. alot of complaints about them.. but, the fuel mileage doesn't sound right that's for sure.. if it was tuned right you should have had decent fuel mileage..

My current headache is an 81 coupe. originally carbed.. I should have just converted it to FI like I was planning to but I listen to my buddy.. had I went with MY plan the car would be running right now for the most part.. it's almost there.. almost..

no complaints bout the motor.... it was a beast. and i think the fuel problem was cuz we did a few things different after we got ahold of it. i belive we had it timed at 18 and the FPR was fully open. we did go to 30lb injectors when it had 24lb ones'.

going FI is way better I THINK, cuz u can control things easier then going carb. and an 81 huh?? dont see to many 81's these days.

[speedfreak87]

no complaints bout the motor.... it was a beast. and i think the fuel problem was cuz we did a few things different after we got ahold of it. i belive we had it timed at 18 and the FPR was fully open. we did go to 30lb injectors when it had 24lb ones'.

going FI is way better I THINK, cuz u can control things easier then going carb. and an 81 huh?? dont see to many 81's these days.


timing seems a little high.


Actually carb is easier, and you can get a little mor eout of them..
Yeah, 81 coupe, no option.. should weigh in around 2400-2600 pounds.. maybe less.. motor alone I'm going for low 11's, 10's on bottle qith a 150 shot.. if it likes the 150 I'll step it up a bit.. I'll live onthe edge a little while.. I would like to get it up and running NOW so I can make a little money with it, buuuuuuut.. gotten have money to make it, and the funds are depleted right now.. all I have left is the fuel system and some guages and I can start the thing.. oh yeah i have to put the motor in it. but that's an hour job. then fabricate a bracket for the tranny cross member. but it's pretty much done.

[Masshole]

timing seems a little high.


Actually carb is easier, and you can get a little mor eout of them..
Yeah, 81 coupe, no option.. should weigh in around 2400-2600 pounds.. maybe less.. motor alone I'm going for low 11's, 10's on bottle qith a 150 shot.. if it likes the 150 I'll step it up a bit.. I'll live onthe edge a little while.. I would like to get it up and running NOW so I can make a little money with it, buuuuuuut.. gotten have money to make it, and the funds are depleted right now.. all I have left is the fuel system and some guages and I can start the thing.. oh yeah i have to put the motor in it. but that's an hour job. then fabricate a bracket for the tranny cross member. but it's pretty much done.

it was either 16 or 18. we turned it till it started tickin and then turned it back 1. but it was high i kno that tho.

well i only said FI was easier cuz i cant tune a carb 2 save my life :lol:
and thats wickid light!!! damn

[speedfreak87]

it was either 16 or 18. we turned it till it started tickin and then turned it back 1. but it was high i kno that tho.

well i only said FI was easier cuz i cant tune a carb 2 save my life :lol:
and thats wickid light!!! damn


I can't tune one either.. lol! but I'll be learning. lol! it's pretty easy to do though.

yeah. I was going to put an interior back in it, but I'm not sure.. I have the 1/4 plastics for the rear, but I don't know.. once I have it running I'll weigh it, if it's at 2600 with me in it, it stays gutted. lol! if it's more then that I'll put the interior in it since it wont get any lighter.. but we'll see. there is literally nothing in the car..

[Masshole]

2600lbs is still lite.... i had alota fiberglass body panels and mine still weighed 2955 with me in it. and bout half tank too.

[speedfreak87]

this thing is gutted.. we'll see though.. few more months maybe..

[91whitepony]

my buddy has an 88 and he put mass air on it and it still seems to run rich, so we are just gonna hang a carb on it and bounce.

[Masshole]

my buddy has an 88 and he put mass air on it and it still seems to run rich, so we are just gonna hang a carb on it and bounce.

dont give up on it that easy... gotta tune the car and adjust things first.