duowing

Alright I was driving my Turbo yesterday, and it still seems like before 2500rpms when the boost kicks in the car really does have a lack of acceleration, but then at other times it seems to run alot quicker and get up to speed faster. It's just really annoying for turning out of places and coming off of lights.

Now I know j said the Turbo's ECU makes up for lower compression by advancing the timing, but my Non-turbo still gets going from a stop faster and it's a 2+2. After reading thxone's posts, is it possible my O2 sensor could be wonky? Could the faulty air regulator maybe if it's not closing all the way cause a problem? Or would the exhaust leak be enough to do this? Other than that the car runs pretty well, but I'm just trying to work out these small running issues.

thxone

I am willing to bet it is a combination of those things. I know an exhaust leak will make bottom end acceleration suffer slightly or alot depending on how bad it is, I could feel the difference when I sealed up my biggest leak and obviously the O2 will cause some surging and bogging while driving...you know what to do man.

duowing

You said you used that copper stuff to seal up a leak? Did you attempt to try any around the manifold?

thxone

I just put it on the flange...I am sure it is the hottest part being it is where all the exhaust is at one time. here check the pick, it has been since the 7th of june and it still looks like this with no leaks.

Attachment 4811

Oh yeah, and it is only held on by one stud...and the Ultra Copper (Permatex)

NismoPick

Duowing:

#1... How much boost are you running?

#2... Do you have an air/fuel gauge hooked up?

jfairladyz

my turbo motor accelerates before boost just as well as my non turbo did. If I part throttle my turbo so it stays out of boost it feels like it has just as much, if not more pick up then my non turbo did too. Of course, my turbo is still using the non turbo 5 speed and the 3.9 rear end

duowing

I'm running the stock boost. Also I don't have an A/F gauge. Like I said sometimes it seems just fine, other times it seems like the pickup isn't as good.

NismoPick

An a/f gauge will help a lot. Then you can easily see what the a/f ratio is when it's not running right.

duowing

Oh one more question I had was. If you set the timing, then replace the plugs and wires, clean up the distributor cap a little. Would the timing need to be reset? I would imagine that even if you weren't getting a full spark, it would still be matched up with the number one spark plug.

Also any recommendations on an A/F gauge to get?

jfairladyz

the timing will NOT need to be reset unless you turned the distributor body itself. It couldn't hurt to check it incase the cap for some odd reason is off, but other than that it should still be spot on. I've never had to reset timing after changing those items unless the timing was already off.

And any A/F gauge will work. Any gauge that relies on a narrow band sensor is going to be very limited in what it can tell you and wont be able to give you an accurate reading any ways. All's you're looking for with an A/F gauge is whether you're lean or rich. Dont rely on it to tell you by how much. So in using it that way, any cheapo unit will do. No sense in spending a bunch of money on something when a lesser brand will do the same thing.

duowing

Well I was driving it around just a bit ago. I think my problem is that when it seems to really be pulling is that I'm not giving it alot of gas because something's right in front of me. My question is, when does the ECU retard the timing? Right as you go into boost? I seemed to notice that as long as I kept the boost gauge's needle a bit awy from 0, I seemed to pull more. Where as it seemed like I had a harder time if I gave it alot of gas right from the go and I hit boost. But from a standstill even with an auto in drive these things can get moving. I'm really looking forward to doing a transmission swap. I'm waiting for slow n' steady to come through with the transmission. It might help if I kick the gear down and just make sure to keep it out of boost is what I'm thinking. Would I be correct in this, or should I still be able to pull well even giving it alot of gas from a standstill?

I'm still waiting for that air regulator to get here. Tonight was a bit cooler, and the car was really stumbling until it got warm.

thxone

I know on the two turbo vehicles I had (88 Ranger/85 turbo coupe T-Bird engine and the 87 Shelby Charger GLHS) both 5 speeds, they would pull decent to about 2700-3000rpms then the turbo(s) would kick in and in the words of The Bandit...Bye Bye Baby!! With part throttle and full they would pull pretty damn hard but when the turbo(s) weren't making boost they just felt like normal cars. Man I miss my turbos...see, now I am yurning again...crap!

thxone

Just curious but where is your exhaust leak...before or after the turbo??? Guys, if the leak is before the turbo would it then not be able to make full boost, so at WOT it would feel slugish?

duowing

My exhaust leak is actually at the front and back of the engine. I have a leak on the left and right ends, where the exhaust manifold meets the head. I ran seafoam through the car, and I knew since it comes out all white that it'd be a good way to see where an exhaust leak was. Sure enough I did have some white smoke coming from between the manifold and the head. That's why I'm planning to try and fix this soon. That rapid clicking from the exhaust leak kinda gets on my nerves.

thxone

I am willing to bet that is 75% of your problem, the leak is anyway. Just my oppinion, hopefully some of the other guys on here will put in their 2 cents.

duowing

That's my guess too. I'm gonna have to learn to do this anyway. Since the same damn studs are broken on my turbo and my non-turbo... Well once I know how to do it, the other one won't be nearly as hard or long.

thxone

Hey buddy, i know how you feel. I had 2 leaks, the one from the pic I showed you earlier in this thread and I have one more at the #6 cyl. My stud is busted off too. I felt a big difference in the car for the better when I temp fixed the first one so I know when the other is fixed it will be awesome...good luck man.

duowing

A quick question about the differential. Is it the higher the number the quicker the acceleration? So 3.9 accelerates faster than 3.5? Cus I was playing GT4 and I think it told me it was the other way around which didn't seem right.

lww

The #1 and #6 exhaust manifold studs are the most commonly broken due to the flex rate in the aluminum head being different from the flex rate in the cast iron exhaust manifold.

Get a new grade 10.9 stud kit (factory is grade 8) for your manifold at:

http://www.freewebs.com/pallnet/products.htm

lww

Yes. The 3.9 Diff gears turn 3.9 times for every one revolution of the drive shaft. Multiply that by the gear in the tranny you're using and you can see the difference in acceleration.

The 3.5:1 first gear in my T5 x the 3.545:1 differential gears in my Quaife LSD = 12.41:1 final drive ratio. So the crank shaft is turning 12.41 times to every one revolution of the wheels.

The 3.062:1 first gear in my '83 5-speed x the 3.7:1 diff gears in my '88 Turbo LSD = 11.33:1 final drive ratio. The crank shaft is turning 11.33 times to every one revolution of the wheels.

You can make this calculation with any tranny/diff combo to find out which one is going to give you the best acceleration through the highest final drive ratio.

Bear in mind, this will also throw off your speedo unless you swap in the appropriate speedo cog for the rear-end you're installing.

The higher ratio's will also affect your gas mileage...

duowing

Thanks for the info on the differentials as well as the link to the site. I'll definitely order the studs from there. I see no downside to going with stronger studs. Which am I better off getting? The L & KA Series 10.9 grade exhaust manifold stud kit, or the L Series 10.9 grade exhaust & carb manifold stud kit? The first one looks like it has 8 studs and 3 bolts. I thought there were more than that? Let me know which is the better to get kit.

jfairladyz

Going back to the leak... my turbo engine had a pretty decent leak at the end of the exhaust manifold (where the stud had broken off) and it had a very hard time hitting boost before I tore everything down and cleaned and repaired everything. I fixed the leak and ported my exhaust manifold, downpipe, and turbine housing and after my first test drive it boosts lightening quick. Will hit 10psi in the blink of an eye.

And I can mash my throttle from a stop in my turbo without any problems. It just goes. Once I realized my boost controller was out of whack though I tried to stay off the accelerator

lww

That depends... do you have carbs on your car?

Yes, you want the first one with 8 studs and 3 bolts. You'll notice your exhaust manifold has 11 attachment points.