Trick Flow R series, with SPEED density??????

dixal

New Member
Aug 28, 2002
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kansas city, MO
i installed a trick flow r series intake (upper and lower) on my speed density equiped 86 gt, the car will start and idel fine but will not rev up quickly and not very much at all. is the problem the speed density? do i need to convert to MAF??? someone told me it might be a VAC leek but i checkd for all that and i donot believe that is the problem. DO i need a bigger TB?? i'm out of ideas on what the problem is!!!! ANY ONE GOT ANY SUGGESTIONS?????
 
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Yes, I've got one suggestion. If you're sure that you do not have a vaccum leak then replace the vaccum hose that runs from the MAP sensor to vac tree on the bottom of the intake. DO NOT DISCARD THE STOCK HOSE! There should be a .070 orifice in that hose that is stock. You will want to replace that with a hose that has no orifice in it then try revving your motor to see if that fixes your problem. If it doesn't, you're back to the drawing board. It's important that you try and preserve that stock hose as best you can or at least remove and keep the orifice that is in there so that you can put it into another hose. Some speed density cars run like ass when that orifice is not there. Hope that helps.
 
If you have a stock cam and stock heads, that intake is doing more harm then good...
The short runners are killing your bottom end and your stock cam wont rev high enough to take advatage of the shorter runners
 
Yep... stock heads on an 86 suck. Ford's experiment with swirl ports on a Mustang. You can take em off get em ported and unshrouded then you'll have a decent set of heads but the money is better spent on new ones. The trouble is finding heads for your 86 flat top pistons that don't have piston to valve clearance problems. Trick Flow has a couple of different ones but you need to call them and speak with them directly to ensure you get the right ones. I've heard tales of the GT-40 heads fitting without problems but again you'll need to call. Since I looked into it last they've come out with a few different versions of the GT-40 heads and I don't remember what's what.
 
check your tps. Scan for codes. You can run any heads and intake, with sd the cam is the big issue. NX264HR Crower 15511 are both great SD cams
 
You may not be able to create the vacuum levels of an SD intake with that large cross section intake - that makes the MAP think the car is under more load and may be making it run rich - hence running sluggish. Checked the plugs?
 
Daggar said:
Hey dixal. Lemme know what you find once you remove that orifice. I'd like to know how many cars it works on vs. how many it doesn't.


I know for a fact that I replaced that hose with a new one. I just replaced all of them that I needed for sure when I did the injectors. Didnt seem to change my SD car at all. I am not calling BS, but I find it interesting that I never have heard of an orifice in that line. This makes the gears turn a bit in my head. What if I install a valve in that line so that I can cut it off incrementally? I am sure someone has thought of it before, but is there any chance this could be used as a tuning tool?
 
jerry beach said:
I know for a fact that I replaced that hose with a new one. I just replaced all of them that I needed for sure when I did the injectors. Didnt seem to change my SD car at all. I am not calling BS, but I find it interesting that I never have heard of an orifice in that line. This makes the gears turn a bit in my head. What if I install a valve in that line so that I can cut it off incrementally? I am sure someone has thought of it before, but is there any chance this could be used as a tuning tool?

I suppose that it could. It did not help me to use an orifice on my particular application however. The more I restricted that vac line, the longer it took for the motor to spin up so on my car it's been completely removed. In other words: My throttle response improved by removing the orifice. When I attempted to do the same to a friend's 88 we did not get the same response. His car ran very rich and there was a noticable loss of power when he got on the road. The purpose of the orifice seems to be to slow the equalization of vacuum to the MAP sensor. I'm not sure why. It may be that most MAP sensors tend to "over react" to a sudden change in vacuum (just speculation at this point). It's why I'd like to get and idea of how many work well without the orifice and how many do not.

Edit: knowing though, that I've seen 2 cars perform badly without the orifice I want to make sure that he didn't toss the thing out without being sure.