New 86 GT Speed Density What CAN\CANT Do

bryanrevans · Sep 13, 2004

I just bought a 86 GT w\ 71k Bone Stock (Had silencer still installed).What can i do and still maintain good driveability.I want to keep it a street driver and want to avoid doing a mass air conversion.Other than k&n,pulleys,Flomasters,cooling.I want Power improvement.I cant even bump the timing pass 14 cause of heads.How do people w\SD still do all these mods I see?????Help thanks!!!!!

N8Miller · Sep 13, 2004

Daggar (i think) is running speed density and heads/cam/intake. as for your setup, i would do a set of ported e7s, rpm intake and other bolt ons what you were mentioning. The timing also depends on octane, so if your running less than 93, you cant go over 14*.

bryanrevans · Sep 13, 2004

Yea Dagger posted solution to my map sensor problem and I nocticed he had Speed Density!!!!!!!yet he has monster upgrades!!!!Still I was wondering if you can program cpu to make fuel air adjustments IE mass air?????The 86 has fast burn heads oops unique to that year only and dont alow 4 over 14 timing adjustment I think????If I upgrade intake will the cpu adjust ratio even though i have no mass air?????

Daggar · Sep 13, 2004

You can get away with allot with SD. The big difference is that most of your tuning will have to be done mechanically as opposed to being done through the computer. For heads... I still rcommend the Twisted Wedge. It "should" keep you from having to knotch your pistons provided you're careful with the cam. I've heard of several others who have knotched their pistons while still in the car but I opted to avoid that (probably due only to ignorance). The E-cam cased me some headaches initially because the vac due to the cam was a bit less than stock. You may have to have the fuel tables on the SD computer changed (reprogrammed) to adapt to what the MAP sensor is seeing at different levels of part power. If you want to make all of your power normally aspirated you'll definitely have to get the computer reprogrammed. At that point even I (a die hard SD freak) would have to question if a Mass Air system wouldn't be the best thing to do. For supercharged applications I'd say keep your mass air and watch your cam. If you plan on running a cam with any overlap it will be difficult (if even possible) to retain the SD. And even it is possible I doubt that it would be worth the expense or effort. SD tries to keep the AFR at a constant 14.7. Great for gas mileage and smog; not so great for making power or for power adders. Things like variable FMU's, larger injectors, and electronic fuel pump boosters make it possible to 'trick' the computer into sending a hell of a lot more gas than it thinks it is. If you plan on doing any serious mods with your SD then I can't stress enough how imprtant it is to permanently install a wideband 02 sensor and reader. It makes tuning a hell of allot easier if you know what's going on. I plan on keeping my SD to the bitter end (who knows why? lol). I hope some of this helps. I guess the bottom line is "Yeah" you can do the mods but you have to be more careful what you do than the Mass Air guys do. Unless you've got a completely programmable EMS that deals with SD it can be a trick.

bryanrevans · Sep 13, 2004

Wow!! alot there thanks!!!Id love to keep speed density but id need a phd to do what your talking about.You know your *****!!!!!!

CRASH7772 · Sep 13, 2004

You can do pretty much everything but a aggresive cam. I am trying to see how far I can push the SD. Last dyno was 225hp and 298tq (see link in sig) but mostly stock. I have alot of go fast parts to add, just need to find the time and place to do it.

bryanrevans · Sep 13, 2004

When you did your T.b.how does it now idle???800 rpm????

CRASH7772 · Sep 13, 2004

bryanrevans said:
When you did your T.b.how does it now idle???800 rpm????

I assume you are asking me.....My idle is around 900. Stupid me tried some carb/choke cleaner and now the throttle hangs and surges a bit but is slowly going back to normal.

bryanrevans · Sep 13, 2004

thanks

a885.0 · Sep 13, 2004

Iam also trying to stay with SD for as long as i can i did all the mods in the sig along with a crower cam that works awsome with SD, i didnt have the money for heads at the time i did the cam but this winter iam goin to buy AFR 165's with the 58 cc chambers and hopefully make around 300 at the wheels iam curently at 244 horse and 291 torque at the wheels. The guys over at www.50tech.com know a good deal about speed density i would recomend checking that site out.
Adam

UnderPressureGT · Sep 13, 2004

i recently did a blower on my car.. stock motor, 65 mm TB.. stock fuel system.. vortech A trim at 5 psi (going to be upped to 8 soon).. the only thing i needed was a vortech SD kit (one way check valve) for my map sensor.... It runs strong as hell and tomorrow i should have 24 lb injectors and a TFS track heat installed

bryanrevans · Sep 13, 2004

Why is it that I always hear that you must!!!!! do mass air conversion if you are going to do any cam,head,or even intake work???????????

CRASH7772 · Sep 13, 2004

I would like to see 250rwhp on my next dyno pull. I have port matched the intake to the TB, changed to Redline 10w-30 synthetic (finally changed valve cover gaskets man those stockers where shot), and once I drop my TKO, clean my 5 year old K&N (never been cleaned) aluminum flywheel/driveshaft, Pro-Chamberand possibly bump timing. I would think 250rwhp is a good number to expect and I would really like to break the 300rwtq. Like I said above, I made 225/298 with old crappy oil, dirty K&N, 89 octane gas, and stock timing. Anybody think a 25rwhp gain with the above mentioned is possible?

CRASH7772 · Sep 13, 2004

bryanrevans said:
Why is it that I always hear that you must!!!!! do mass air conversion if you are going to do any cam,head,or even intake work???????????

Like I said, you can do it all except a radical cam because of the vac/manifold pressure. Nuff said....we need to start a SD only section.

Daggar · Sep 14, 2004

CRASH7772 said:
Like I said, you can do it all except a radical cam because of the vac/manifold pressure. Nuff said....we need to start a SD only section.

You can even do a cam if you have the fuel tables adjusted. The limit is running a cam that steals almost all of your vac (pretty radical). If you ever get into a situation where you have to use a Vac pump or cannister then I'd say your SD days are pretty much over.

CRASH7772 · Oct 3, 2004

Daggar said:
You can even do a cam if you have the fuel tables adjusted. The limit is running a cam that steals almost all of your vac (pretty radical). If you ever get into a situation where you have to use a Vac pump or cannister then I'd say your SD days are pretty much over.

Any suggestions on a cam to run? I have some Stage 2 ported Windsor Jr's that I need to add some lift for them to work to their potential. I have 1.7 roller rockers which I figure that might get my to .480 lift. I would like to break .500 lift on these. Any ideas without messing with the SD to bad? I've heard alot about the Crower cams on SD cars but what kind of lift do they have?

Daggar · Oct 3, 2004

CRASH7772 said:
Any suggestions on a cam to run? I have some Stage 2 ported Windsor Jr's that I need to add some lift for them to work to their potential. I have 1.7 roller rockers which I figure that might get my to .480 lift. I would like to break .500 lift on these. Any ideas without messing with the SD to bad? I've heard alot about the Crower cams on SD cars but what kind of lift do they have?

I'm no cam expert so wouldn't even begin to try and recommend one for your setup. I used the E-cam mostly because it wasn't too radical and the lift is within the limits recommended by TF for my flat top un-knotched pistons. As far as how it will effect the SD? That will depend on how much a difference it makes with your Vac. You may end up having to get a custom chip burned so that the computer can make the "correct" adjustments to fuel and timing for your combination. I will note that cams that leave you with little or no vaccum will probably not function at all with SD (since SD works primarily from the Vac it sees from the MAP). A cam with a big overlap.... forget it, but lift by itself shouldn't be out of SDs ability to cope.

Hey cam guys.... any suggestions?

tmoss · Oct 3, 2004

Daggar said:
SD tries to keep the AFR at a constant 14.7. Great for gas mileage and smog; not so great for making power or for power adders.

This is ture only in "closed loop" normnal driving. When you push the accelarator to Wide Open Throttle (WOT) the computer ingnores the O2 sensors and stops trying to hold 14.7:1 A/F ratio and goes to a programmed fuel table in the EEC which richens the mixture. SD does run on a leaner EEC table tune that the MAF cars though.

Daggar · Oct 3, 2004

tmoss said:
This is ture only in "closed loop" normnal driving. When you push the accelarator to Wide Open Throttle (WOT) the computer ingnores the O2 sensors and stops trying to hold 14.7:1 A/F ratio and goes to a programmed fuel table in the EEC which richens the mixture. SD does run on a leaner EEC table tune that the MAF cars though.

Good call... especially when you start talking about adding boost or nitrous at WOT. No more benefit of sensors to help keep things right. Makes it that much more important to have a wideband 02 reader and also why FMUs work so well with boost. A custom chip burned with fuel tables for a specific application can fix any problems in this area as well (so long as the injectors are large enough). Thanks tmoss

CRASH7772 · Oct 8, 2004

I'm gonna start a new post about the cam thing I guess, this thread doesn't seem to have the answers I need at this point and time. But we did learn a good amount about the SD systems.

New 86 GT Speed Density What CAN\CANT Do

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