Bigger secondaries with stock ECU?
 

Can I up the secondary injectors and use the stock ECU?

Will the injectors cause me to fail the emissions test (i.e. what rpm to they kick in)?

I have an 88 TII engine that I'm putting in my SE. Planning on k+n custom cold air duct, RP downpipe and high flow turbo cat with an 84/85 RB powerpulse muffler, and maybe a small street port. Also, porting waste gate and a installing walbro 255 fuel pump.

The reason I'm thinking of using bigger secondaries is because with a FCD I don't want to lean out if the boost gets to 8-10 psi. Maybe I don't even need the bigger secondaries. I'll probably build the diy FCD which seems to do a better job on the boost signal.

Maybe I could convert my existing 84 SE 680cc LI injectors to use in the 88 engine.

Hope I covered it all.

Thanks in advance for your help,

Scott

You'll run very rich and lose some power if you upgrade the injectors without adding a fuel computer to tune the mixtures. A better idea would be do dyno it straight after the mods are complete to check the mixtures. With the upgraded fuel pump (and if boost is kept under control) you'll probably find you don't need to change the injectors.

someone correct me if I'm wrong but I think if you're going 3" all the way, the powerpulse may be two restrictive. I'm personally going with a 3rd gen RB dual tip muffler. Also I was under the impression that the walbro 255 fuel pump was intank. Also remember if you decide to use the GSL-SE injectors you might have to add 10ohm resistrors.

check this out http://www.rotaryresurrection.com/injector.html

good luck

i heard that the powerpulse is really good and not that restricted..........
i was thinking about getting one

You guys hit upon some good points.

First off, I'm only looking for like 200-220 hp and I don't want a level of boost that gets me into trouble with detonation. Also, I really don't want to use a custom ECU which == big dollars and will have the trouble of tuning it.

So I need to be careful and not create too much boost. Yes the 84/85 powerpulse will probably be a slight restriction, it's 2" pipe vs the 2-1/2" pipe from the bonez RP system. Hopefully just enough of a restriction to keep boost down. It looks like it can handle the flow--I'll let you know. For me it's an easy install vs. something real custom.

The Walbro 255 also comes in an external version that can be ordered with various types of fittings. So I just need to order the right one.

I'm hoping to hear more members like NZConvertible say I don't need to upgrade the secondaries--especially considering the boost and hp levels I'm looking for.

luiml73: Yea I saw that FD muffler also and I really like it--but the inlet looks like it is at some strange angle pointing down almost. What's up with that. If you figure it out let me know--all I could figure was cut off the nozzle and have it welded in at the right angle.

Scott

I did'nt know that the walbro came external (learn something new everyday).

BTW. listen two what NZconvertible says. Thank's to him I have my car running perfect. I'm using stock 550 injectors with no FCD running 7lbs. (NO BOOST SPIKE).
The car is running awesome. I'm going to the track next week and I'll let you know what I ran.

Luis

http://www.fuel-pumps.net/500.html

Here's the link if anyone else is interested.

Rex4Life I was reading the post that NZConvertible said,
if you run bigger injectors in the secondaries your car is going to run pig rich without some type of fuel controller.
"I know this because im running pig rich right now as we speak" My set up is the following 88 S4 T-II with Full R.B. Exhaust system, intake, home made FCD, double pulleys on the alternator,Magnecor R-100 plug wires, running 9"s all the way around in plugs,my motor is ported on the exhaust side and "JUST A CUNT HAIR ON THE INTAKE SIDE" as well. Im running stock injectors in the primaries and Greddy 720's in the secondaries, with this set-up like NZ said im running way to rich. My car ran a lot better when I had the GSL-SE injectors in the secondaries. Im also running the stock intercooler with this setup my car is runnin a 13.7 quarter mile. Im runnin that time with the SE injectors, I have yet to try it with the 720's as I already know that my car will not run a good time. I got the Greedy 720's as a "Insurance Policy" cause I always like to go at it on the highway, so I installed the 720's for that extra margin of error as far as fuel is concerned, just to make sure I dont lean out.
Oh by the way Scott your car "WILL" hit 10-11 PSI with the full exhaust setup.

Thanks for the advice Donn,

Does your RB exhaust still have a cat or just a pipe?

Looks like my idea of using bigger injectors with the stock ECU won't work. Maybe I can get some margin with the Walbro, I saw a fuel calculation worksheet and having higher pump outlet pressure allowed for a higher hp output. http://www.maxcooper.com/rx7/how-to/...tem/calcs.html So I'm guessing if the hp is not increased then maybe the detonation margin is increased--ie maybe more fuel is being injected cause the rail pressure is higher.

Also, looks like I won't need a street port as I'll have enough problems with too much boost.

I think I will install the stock TII exhaust on with the GSL-SE intake filter. Then mod the intake and see what kind of boost #s I get. Then go mod the exhaust if sufficient boost margin exists.

I'm really hoping that with the K/N intake mod, RP exhaust, and RB powerpulse muffler I end up with no more than 10 psi boost max. Certainly is a fun experiment.

If I get more than 10 I'll have to take it easy till I can figure out what to do.

Scott

donn's car does'nt have a cat. We don't have to worry about that here in florida anymore. If you're wondering how I know about donn's car is cause he's been a good friend of mine for 12 years. As a mater of fact I'm going to smoke his ass at the track next week. Is'nt that right donn?;)

fc vs fb place ur $bets
http://www.teamfc3s.org/forum/attach...&postid=100617

BTW scott in this pic my car was running 680's and was running to rich (car ran like shit). But I'm sure other people here don't have that problem. Hopefully others will give their input

Luis