Doesn't want to rev past 5K rpm, normal?

Rdrcr · Aug 2, 2007

I have a completely stock '86 GT 5.0 5-spd and the car does not like to rev past 5,000 rpms during hard acceleration, is this normal? The power band seems to run out at around 4,800 - 5,000 rpms which leads me to believe that it could be pointless to pull the car past the 5k mark. However, redline is indicated at 5,800 and the engine does not seem capable of reaching it?

Any thoughts?

Mike

85_SS_302_Coupe · Aug 2, 2007

How does it rev in neutral? The rev limiter is at 6250....in neutral if it revs ok to that point but not when driving, it could be a few different things. It could be something like valve float or a misfire. On a stock engine your peak hp/tq is falling off by 5k so it would be pointless to run it past that point anyways.

Mr. Rustypwnz · Aug 2, 2007

he has e6 heads its not gonna rev past that if it wanted to.

RS200 · Aug 2, 2007

Keep in mind the stock tach sucks.

Ike83 · Aug 2, 2007

Only real way to tell is to invest in the Autometer.

Mustang5L5 · Aug 2, 2007

Bone stock '86 isn't going to rev much past 5000 anyway. The tb/intake and heads are smaller than the 87-later design. At least consider an upgrade to those if not better parts

Rdrcr · Aug 2, 2007

Thanks for the replies guys.

I was thinking it had something to do with the factory heads and intake. I just wanted to get some feedback from you folks regarding the sudden slowdown in the upper rpms.

Mike

Mr. Rustypwnz · Aug 2, 2007

its no the tach people e6 heads dont make power past 4k. put at least some e7's and a good intake and cam in it, it will be night and day!! you might have to notch the pistons though just keep that in mind.

ryan218 · Aug 2, 2007

my dad's 86 pulls really hard from 2,500 to 5,500...im pretty sure that the top end of the engine was never touched.....maybe they have been replaced with e7's or something though.

Boss 351 · Aug 3, 2007

Pray your valve spring retainers hold up at 6000rpm...

25thmustang · Aug 3, 2007

ryan218 said:
my dad's 86 pulls really hard from 2,500 to 5,500...im pretty sure that the top end of the engine was never touched.....maybe they have been replaced with e7's or something though.

Does it pull and make power to 5500 or will it simply rev there. I get picked on all the time when I used to rev my stock motor to 5400, and now this one to 5700.

To the original poster, will it rev past 5000 RPM, it is just not making power? Or will it stop pulling altogether? If it revs past that but isn't making power, then no issues at all. If it stops revving at 5000 and wont go past that, then there are more issues.

Rdrcr · Aug 3, 2007

slow95gt said:
its no the tach people e6 heads dont make power past 4k. put at least some e7's and a good intake and cam in it, it will be night and day!! you might have to notch the pistons though just keep that in mind.

I plan to build a engine sometime after I purchase and install a supercharger. At the moment I am driving and running the car to test it's reliability and strength. I know that I have flat top pistons which is why I want to piece a engine together built with new components. This way, I can finally give the local kryophysics some business.

Mike

Rdrcr · Aug 3, 2007

Boss 351 said:
Pray your valve spring retainers hold up at 6000rpm...

I want to replace the retainers, springs, pushrods, and rockers NOW. Any suggestions to some bolt-on roller rockers and springs for the stock motor? I don't want to run this thing very hard until these items are replaced.

Mike

Rdrcr · Aug 3, 2007

25thmustang said:
To the original poster, will it rev past 5000 RPM, it is just not making power? Or will it stop pulling altogether? If it revs past that but isn't making power, then no issues at all. If it stops revving at 5000 and wont go past that, then there are more issues.

Yes, it will rev past 5K, but very slowly. In fact, it really struggles past 5,300 rpm. I would not say that it stops pulling, I just don't have time to wait until it gets past 5K.

Sounds like that is the nature of the beast.

Mike

Rdrcr · Aug 3, 2007

Double post.

85_SS_302_Coupe · Aug 3, 2007

Sounds like it's time to hit up the salvage yard for an Explorer long block...that'll solve all your problems and give you a little boost in power at the same time.

Aliate X · Aug 3, 2007

Rdrcr said:
Thanks for the replies guys.

I was thinking it had something to do with the factory heads and intake. I just wanted to get some feedback from you folks regarding the sudden slowdown in the upper rpms.

Mike

Yup my stock 5.0 was exactly like that, its like hitting a wall at 4800, invest in a good head/cam/intake setup and the thing wont want to stop revving, its a night and day difference. If you dont pay attention with a good hci youll hit the limiter ever now and then lol

ryan218 · Aug 3, 2007

25thmustang said:
Does it pull and make power to 5500 or will it simply rev there. I get picked on all the time when I used to rev my stock motor to 5400, and now this one to 5700.

To the original poster, will it rev past 5000 RPM, it is just not making power? Or will it stop pulling altogether? If it revs past that but isn't making power, then no issues at all. If it stops revving at 5000 and wont go past that, then there are more issues.

its pulls hard to 5,500 then the nose starts to drop as if you shut the car off or let off the gas..

Doesn't want to rev past 5K rpm, normal?

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Doesn't want to rev past 5K rpm, normal?

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