newpony

From my calculations I have 4.10 gears . My mph was 95 in 4th gear in the 1/4 .i know right after 5k say around 5200-5400 I can feel my car surging and slow down . And that's around 95 mph I believe
I did have my buddy set my timing and I'm not sure if it messed with my rpm and power my car likes to rev .i know my heads are limiting power in the higher Rpms .
Besides all that could the gears be limiting me to trap at 95 . It didn't feel like I needed to shift I ran it all the through in 4th gear

dawson1112

You should add a signature to your account with the year of car and maybe some of if any mods, or stock parts. What size tires your using has an effect on when you run out of gear , but I doubt that's what is happening . You could have a faulty ignition coil that breaks up at high rpm. You could also have a weak valve spring or springs causing valve float , also possible that your fuel system falls out at high rpms ie weak fuel pump , partially plugged fuel filter, old or worn out injectors. There are just so many possibilities .

You say your buddy messed with your timing , but do you know what he set it at ? If it was advanced to far you might be experiencing some pinging and loss of power.

Does it feel like it runs out of power in other gears? If your have stock heads and stock headers they greatly limit your rpm/power range. The engine simply runs out of breath.

newpony

89 gt does it pretty much in all gears only has pullys Mac headers unknow flow master series stock hpipe all cats after market filter bbk rear and upper control arms sport line springs street tires 2 seats 4point cage

dawson1112

Id say that by the time you hit 5200 -5400 your engine is falling on its face because your out of your power band at this time. If you have 4.10 gears and running stock 15" tires that's probly all your gonna get out of it. If you put a set of 16s or even 17s on it with 4.10 you could increase your trap speed to around 110. Also a gt40 explorer intake could net you a bit more rpms before she starves for air. The mac headers are really decent headers , but your stock H pipe is killing it. Get a good after market H pipe , and if you can in your area eliminate the cats . Just those few things could help push your power band up into the 5600 -5800 rpm range.


I have an 89 block in my 94gt, running 3.73 ratio . It would fall out at about 5400 with the stock headers , intake and H pipe with cats. I installed a set of long tube 5/8" headers explorer gt40 intake 2.5 inch H pipe I think the stock H was 2". I have a set of flowmaster super 44s. This moved my power band up to closer to the 6000 mark on the tach But I don't really pay to much attention to the tach as its a stock unit. All in all I threw about 600 bucks at it for the headers H pipe and intake and I think it made a big enough difference that It was well worth the money .

reldla1996

The engine should go beyond 5200/5400 rpm, even if the power is dropping off. Sounds like weak valves or an ignition issue. You're going to need more power to get a 110 trap speed.

mjr46

you're not running out of gear at 95 in 4th with 4.10's, unless of course you have a diesel and are running a dinky tire...lol

newpony

With the rim size change wouldn't. I have to have a slightly taller tire ? I'm running 15s with some cheapers tires . I have a Catless hpipe I just had to do smog test and havnt gotten around to swapping it back out . .I also get since amount of valve chatter I think I'm hearing ? Car acts like its cammed has a rough idle and I spoke to one of the previous owners said he put a cam I'm not sure what kind .
I do think I need to do some fresh plugs . And my coil wiggles its not solidly mounted to the metal case that mount to the car .