I am purchasing a L98 from a 87 IROC was wondering if it is a mass air flow or speed density....

also does anyone have a underhood shot of the routing of the intake hoses and air filter?


Im putting it in a 91 firebird that currently has a ratty old 5.0 TBI, is the ductwork for the intake the same as a 87 IROC or is the Firebird different?

Any cold air intakes worth it?

 

87 was MAF.

For TPI, the Camaro & Firebird air intakes are completely different. The Firebird version will fit the Camaro (with some tweaking), but the Camaro version will not fit a Firebird at all. MAYBE it would fit with some cutting, welding, a new hood & some repainting.

You gonna run the L98 as TBI? Gonna need new programming, bigger injectors, etc. Not just a "simple swap of the long block".

 

any after market intakes you recommend? is the maf itself the same?


and im swapping the whole motor, ecm, harness, fans, everything

 

the camaro picks up its air from the front of the radiator. goes over the radiator. the firebird has a 90* bend and picks up its air from where your battery is. the radiator support area is different and its a very rough fit. all you need is the intake ducting from a firebird or make your own. i just did the same swap but now i wanna make a true cold air.

 

Everything from the maf in is the same on both cars. You will need some extra stuff besides the Firebird intake intake assembly. You will need to install a tpi fuel pump. Your tbi is running @17# fuel pressure if I remember correctly, you need 45# for tpi. You will also need to change out the connection between the pump and the tubing because that thick rubber line used with tbi will blow out under the increased pressure. You will need the ecm from the donor car of course, and the harness needs to be repinned because the tbi electrical connections are different than the tpi.

 

i am getting the ecm and harness, i bought a high volume in tank pump 255 lph its a bbk.

which fuel lines are you talking about replacing? hard metal lines or soft line?

 

the chassis bulk heads have different pinouts. they may look plug and play but def aren't. i did it about a yr ago and it took about 5 weeks of research to move maybe ten wires around. not much documented cause every body just goes to map.

 

what do you mean by chassis bulk heads?

 

The fuel line I was talking about is the connection between the in tank fuel pump and the steel lines going out of the tank to the engine. If you are running an external electric pump, you would have bypassed that connection.

The chassis bulkhead is the connector where the harness goes through the firewall on the passenger side. Helms manuals have complete wiring diagrams for every engine type offered for what ever year you choose to do. If you decide to do speed density, you will need a manual for 1990 to 1992. One manual won't cover all of those years, but any one of those year manuals will cover a speed density system. For the maf system, you don't want to use 1985. That was the first year with a one off computer, and was improved considerably in 1986. 1986-1988 used a ninth cold start injector to enrich the mixture for cold start up. In 1989, G.M. eliminated the ninth injector and put programming into the ecm to enrich the mixture on start up using the 8 standard injectors.

The advantage of the speed density over the maf is two fold. #1 the maf is supposed to correct the "mixture on the fly", but the computer is so slow that it actually corrects the mixture late, so it constantly overshoots and recorrects. The speed density system uses a much faster computer. The second problem with maf is the maf itself is very expensive compared to the less expensive components used in the speed density system.

Below is the link to the Helms manual web page. The Helms manual is the official factory manual. The cheap books that you can buy at the local auto parts store
typically don't have any wiring diagrams.

http://www.helminc.com/helm/homepage...=Google+Search

 

This is what i did for my intake. I used 3" pvc pipe to the maf then right off the maf used a spectre cone filter. the stock firebird intake piping goes right infront of the radiator on a 1 by 3" box that i could see being restrictive so i replaced it with pvc and the air filter box breaths out of an even tinier hole. You can feel the the motor opened up a bit with this intake.