Blue-GTU

Read my sig and tell me what you think I should be running with those mods and then contrast that against my 17.2 best run. I have only run it at Palmdale, 5000 feet elevation but should that make such a big difference? The car seems to be healthy, no smoke, idles fine, and can easily spin the wheels in 1st.
Any ideas?

Scott 89t2

wow that's pretty high. you'd probably lose at least 1/2 sec. but you should be in the 15's with those mods.

mazdaspeed7

I bet the driver plays a very big part in it. I know I cant get the full potential out of my car yet. It is easy to drive, but it is very hard to drive to the full potential of the car. Your times will go down with practice, and Im sure your car could do mid 15's.

sickboy

what was your 60ft etc, got the slip? Driver plays a big part in your numbers. if u cant drive.........you can have 400hp and still not break 14's.

Agent_D

iTrader: (2)

5000ft takes about .9 secs off, im at 5500 and it takes exactly 1 second off the time and i was runnin 15.3 @ 5500ft with my 86 with 5.12 gears so 14.3 @ sea level, yea should be in the 15's as the others said

SuperchargedRex

I don't think the GTU came this way, but that doesn't happen to be an automatic with the 3.909 gears?

supergoat

I believe it's a 5-speed, he mentions a performance clutch in his sig.

Your car came with an LSD from the factory right?

Blue-GTU

Yes, I believe my car has a LSD since it is a 1990 Model.

Here is my best 60 footer.

Reation Time: .385 (oops!)
60Ft: 2.3
T3: 10.958
T4: 14.244
E.T. 17.234
MPH: 77.6

Slight wheel hop but not much. I held on to 1st to about 7K and 2nd to 8K, and 3rd all the way to the finish.

Blue-GTU

Dose any one have any ideas why.. I can drive the car well. I have always pulled everyone for the first half but they gete me at the last bit..any ideas??

rx7_ragtop

A couple of things.

1) Hold 8k in 1st also.

2) You meantion a RP exhaust... but nothing about a high-flow cat or presilencer. A cat-back will gain you essentially NOTHING with the stock cats in place- your biggest gain is by getting a racepipe or at least a high-flow cat and gutted pre-cats. The Bonez units (from RP) are nice, direct bolt-in replacement.

3) If you aren't pulling pretty hard above 5K rpm, your 6-ports may not be opening, or (see above) your cat(s) may be partially clogged. Your MPH is a bit low... I am hitting 85 in my convertible, which is a bit heavier than your car- but I'm at about 800 ft. here in the Dallas area. Your elevation DOES hurt you a bit.

In short, replace your cat (again, the whole RP NA downpipe/cat, or better yet the racepipe or similar) and make sure your six ports are opening. Also I would expect your 60' to be better- I hit that with my car, which is heavier with a 3.909 diff and no LSD.

Brad

Sebring7

Get these things fixed like the rest of the guys recommended, then go run it at Pomona! I ran my 86 gxl with the same mods I have on my SE (exluding some parts) while using nitto drag radials, and I ran at 14.4 at pomona

I'm a bomb *** driver foos!

spooledUP7

Can anyone offer a testing procedure for resolving 6 port problems?
Can anyone explain it?

Blue-GTU

This is the system I have.. The local muffler shop will not make a straight pipe for me. They said if they do it and the cops find ou t there is a $10,000 fine for me and the shop,, never heard of the. Know of any places that will do the work? For a good price? I know rp has them but they are $100 plus. not worth it.. If I have to I could do it myself.. Just dosnt look like fun..

Bönez 2.5" SuperFlo System (5-speed)
Bönez 2.25" Double Cat System

MasteRX

Don't you have to pass california emmisions? If so, the best thing for you to get is the Bonez double high flow cat system. It is street legal in claifornia, even passes visual inspection. The single system wont pass visual because '89-'91 cars came with two cats. The system is like $300 or so, but it is well worth it. It is one of the best cali legal mods you can do cause it virtually eliminates the restrictiveness of the stock cats. A good total exhaust system is the most important part of building horsepower on a N/A RX-7.

t_mak@mail.plymouth.edu

Blue-GTU, your time doesn't sound that bad, when my car was bone stock, I ran a 17.218 @ 80.39, with a tune up, I got down to 17.002 @ 81.94, Now with gutted cat and intake I got down to 16.755 @ 85.00. You should learn that the 89+ NA are not the fastest thing out there. Even Road and Track could only get 16.7 out of a GTUs, but your time does seem a bit low, especially the trap time, I think you have either a clogged cat or stuck 6 port or failed VDI. My cat clogged at 95K, it was so bad that i couldnt even redline the car in 1st gear, i gutted it, now car pulls hard from 6K-7K. I have a 90 GXL with virtually no mods other than aluminum hood, gutted cats and a cut intake box (Had a cone but didnt like it). I can probably gain a tenth or 2 if ic hange to a cat back because i have these really restrictive exhaust. Get this, I have gutted cats, my car is still quiet. Another thing to look at is to shave down the weight, for example I weight my car a long time ago with 3/4 tank of gas, it scaled in at 2881lbs. If you can shave the weight down, it would help a lot since our cars are torqueless. I think my trap time says it all, at 85mph, i should be doing low 16s, but then lack of torque down low really hurts. Anyway hope it helps. Good luck

Mykl

I had a '90 GTU and it had an open diff. I'm pretty sure yours does too, unless the LSD was available and purchased as an option when the car was bought brand new.

t_mak@mail.plymouth.edu

LSD was only available in turbo and GTUs in 89+, no NA car had LSD unless it was modify, on NA cars, it wasnt even an option

Blue-GTU

Ok my mistake.. I have.
Bönez 2.5" SuperFlo System (5-speed) (single cat, presilincer)
RP50 Performance Cat-back Exhaust.

The weight was low. 1/4 tank gas, but i did have my speaker box in the back.. and still ran the 17.2. could remove it next time.

The cat is only a yr old or less dont think its clogged..

as for the vdi it has never been replaced of checked, as far as i know.. guess i will be checking it, to see if it works..

Blue-GTU

I helped Blue GTU out with checking the compression, and according to the Pss, Pss, Pss test and the nedle valve removed on the tester, Blue's compression is just above minimum (85 psi) at 90 or so on the front rotor faces, and close to 100 on the rear. Could this cause a major reduction in trap speed? I'm not sure what RPM is produced by the starter, but if lower than 250RPMs he could have even better compression than what the test showed.

I am still curious if anyone can offer there experience in solving VDI, 6-port isssues.

WE replaced all the stock hoses a while back with the exception of a few hard to reach ones under the manifold. Are there any critical hoses that could be related to the VDI system?

spooledUP7

The above post which starts "I helped Blue GTU..." was my mistake. I helped Blue GTU with his sig and logged on with this browser. Damn cookies thought I was Blue GTU.

So, I hope this clears any confusion when reading the above post.

Mykl

I ran a 16.2 in my '90 GTU back when it showed compression numbers similar to your own. I had a cone filter and a race pipe.

Rx_treme

No you're not right about the only GTUs and TII, b/c my 86 GXL came with it factory. but i know that the base models didnt.

PaulC

Ok heres my experience. I ran an 84 Monte Carlo SS back 10+ yrs ago with a mild big block. Here and Denver when I was in Tech School with the Air Force. I was running 2+ seconds slower in Denver than in Ennis (south of Dallas) so yes 5000 ft makes a huge differnce. Try making a road trip sometime and drag at a track thats under 750 ft and you'll see a huge improvment. If not then check everything from compression to fuel injectors to clogged cats to coils not producing proper power.

RotaryMan88

Here's my two cents:

My first drag I got a 17.3 in my SE w/ only a cone filter and minimum weight reduction. I was in MD, so it was probably about 1000 to 2000 above sea level. The thing that threw me off on your time, was its speed...you only got about 77MPH while doing a 17.2? There is something clogged or not opening, I ran 17.3 at 83MPH...5mph dif is big when it comes to dragging...now that I've got my 2.5" Race pipe and soon 2.5" custom catback w/ wired 5th & 6th ports, I should hopefully pull a 16 flat or lower

t_mak@mail.plymouth.edu

86-88 and 89+ have different LSD equipment. 86-88 GXL have LSD, 89+ dont

Rotaryman, I know that feeling, i ran 16.7 @ 85. At 85, all these civics and subarus were running high 15s and low 16. There is some serious weight issue in our car...