littlebit421

Can anyone tell me what the hp difference between my 5th and 6th ports working or not working is. Mine are not working and before I pay to have someone fix them I want to know if it will be worth the money. Ive heard all kinds of stuff ranging from 10 to 50 hp loss if they are not working properly.
The car is a 1990 vert all stock except strightpipe exhaust with factory mufflers, and if anyone has proof of the hp readings of them wrking or not would be great. Thanks in advanced for any info.

RotaryEvolution

iTrader: (30)

usually the difference of them not working is ~115 wheel horsepower versus ~140 wheel horsepower with them functioning.

yes they make a rather big difference in power if the sleeves are still in the engine. if they are removed then you will only notice a lack in bottom end response but no difference in peak power.

littlebit421

Thats a good bit of hp loss. Where does that fact come from, or is it just hear say. Im not trying to be difficult. I want the truth, you cant handle the truth. Haha get it. Anyway what im saying is, does anyone have thiss on a dyno or somethin. Again thanks for any input its all helpful.

RotaryEvolution

iTrader: (30)

check the dyno forum, there's a few people who have dynoed with and without and i have personally noticed the differences in power as well on the dyno, although not quite as dramatic but also not on a stock car either.

rotarygod

iTrader: (1)

A 1990 vert makes 140 hp at the crank not the wheels.

RotaryEvolution

iTrader: (30)

unless the vert is detuned without my knowledge compared to the coupes the series 5 is 140 at the wheels, not crank. 143.6 actually, dynoed.

lastphaseofthis

iTrader: (8)

s4=145@fly, s5=165@fly, c'mon rotary god, were you at.. =D

rotarygod

iTrader: (1)

Damn it I had a typo! I didn't mean 140. I misread his post and thought he said 160.

S4 na = 146 hp
S5 na = 160 hp
Both at the crank, coupe or vert.

littlebit421

Good idea on the dyno section, well mine arent wrking and it pulls pretty good ,its a good clean sweep all the way to 8grand. So in everyones opinion is it woth getting fixed.

rotarygod

iTrader: (1)

Without them working (as in staying closed) power will start to fall off after about 4000 rpm and you'll have poor top end power. With them open full time you'll have less power below about 4000 rpm (3800ish). Some people don't mind. I personally can stand them this way and I find it to be quite noticable. I once had a car where they didn't work where I wired them open. When I was just daily driving that car I ended up closing them since for normal driving the trade off wasn't worth it. They work now and they are staying that way. It's up to you but why decrease your usable power band with nothing to gain?

littlebit421

I got a little info, for every 7lbs of stationary weight you lose 1 hp, and for every 3lbs of rotating weight is 1hp. Now thats somethin I heard from some motorcycle gurus. So since I have a vert I only have like 70hp. Damn the heavy vert. Anyway ill tinker with it and see if I cant get them working right and if not ill take it to somebody.

RotaryEvolution

iTrader: (30)

gurus? you don't lose power from stationary weight. the car will be slower however, perhaps they meant acceleration rates.

Rx-7fetish

Your not losing power, that "formula" is used to determine how much power is being used to just make the vehicle move, the leftover is all going towards acceleration alone. Supposedly.

littlebit421

I understand the physics of the whole thing I was just trying to make a joke about how heavy the vert is. I guess it wasnt as funny as I thought. Funny haha not funny queer.

REAmemiya_fan

DO NOT pay someone to have them 'fixed'. To fix them, simply remove the upper/lower intake manifolds, and the sleeves should come out with them. Take them off, give them a good clean. Sand the outsides of them with a fairly high-grit paper (not to actually cut the sleeve, more to polish it). Then clean the inside of the port with a rag over a 13/16 socket IIRC, and spray the inside of the port with some good carb cleaner, then with the socket attached to an extension, simply shove it in and clean up. Follow up with the sandpaper again, and walla, should be smooth as butter.

littlebit421

Its a little intimidating havimg to pull off the manifolds, never done it before. Can I pull them off together or do I have to pull the top then the bottom. Im pretty mechanically inclined, I just dont want to mess something up, the actuators are stuck and while trying to free them I got carried away and broke the one on the front, I got the one on the back to tuen but it was still very tight.

rotarygod

iTrader: (1)

It is far easier to pull them each off individually in sequence that as one assembly. Before you do though, go ahead and buy all new intake gaskets. You are probably going to need them.

littlebit421

What are the torque specs and tightening sequence for the bolts on the manifolds. Or should I look in the fsm

littlebit421

Is there a way to ,ayne free the sleeves without pullimg the manifold just by pulling the actuators and spraying carb cleaner in there and hope they break loose. Thats if the sleeves are stuck not the actuators

REAmemiya_fan

Tightnening torque on all the manifold bolts is 19-24 Nm. No specific tightening pattern, just start on one side, and alternate sides until you reach the middle. Just like torqing your lug nuts, you do them in a pattern that will not warp the manifold.

Not a chance, even with the actuators off, you cannot see into the manifold. The only thing the actuators do is take air pressure from the exhaust (S4) and somehow pull the rod (I have not seen the inside of one so who knows how it works) that turns the sleeves. You HAVE to take the manifolds off to free the sleeves.

littlebit421

Ordered new gaskets last week, waiting on them to come in. will take pics of the work. And what I meant was where the rod that turns the sleeve goes through the manifold, if you take that off and out could you spray enough wd 40 or pb blaster in there to maybe free the sleeves. If thats what is stuck. Im hoping it stuck where the rod goes through the manifold. I broke the rod where it goes into the manifold, I have an,extra though. Anyway I will be working on it sunday and will post if I think there is a significant difference between the ports working and not working. Wish me luck I need it.

gerald m

Wd-40 is suppose to be a lubricant not a penetrating fluid but it is better than nothing .. ..You should get the manifold off before you do any more turning and twisting then you will be able to tell weather the rod is stuck or the port valve .. more than likely the port valve is stuck .. spray penetrating fluid . I would use a vacuum in the port hole just to suck up anything that comes loose so it don't go into the engine if the valve has been stuck for some time you never know what might be inside waiting to get sucked in or fall in .. The port valve actuators should be limbered up by hand regularly , as often as checking the oil to keep them freed up ..this is a very common problem . I don't think that 60% is an unrealistic number of port valves , actuators stuck or needing service.. It's not a hard procedure just take your time . IMO these little engines need to be taken out and opened up ( red line ) now and then just to keep things cleaned out and working proper ..