For those of you who didn't read my other post of my race with him, long story short i lost. We went from 1st gear roll and he jumped like 1 car and then i pull up next to his door and then the quarter was done so we stopped (he also missed 2nd or some ****). He has a $700 exhaust and a complete K&N intake. In that race i had nothing done.

I put in my Greddy intake thursday so i wanted to race him again. We race from a 2nd gear roll and i win by half a car in that race, then we do it again 2nd gear and he beat me by a half a car. The intake did help though believe it or not, it pulls harder i think. I figured i would of gotten a car on him atleast. I do need a XS engineering Ignition or HKS Twin Power because i have high end break-up in between 5000-6000 rpms then it pulls all the way to 7500. Hopefully its just ignition break up. Any ideas?

 

You have an intake so...

1) Put a downpipe on the car! (RX-7 store sells them for 110.00 ! Good for 35hp.)
http://www.rx7store.net/index.asp?Pa...S&Category=400

That one mod will put him in your rearview mirror.

2) Put a cat back on the car (Find a good used one in the 3rd gen for sale section)

3) Tuned Power FC. You can run 13 psi but it will cost you 900 plus.

Ignition breakup...First try this
*Change the plugs and plug wires
*Put on some ground straps
*Run premium gas only

 

Next on my list is the dp, that will fit the stock cat wont it? And for the plugs i just changed the plugs, i have NGK plugs and wires changed like 1500 mi ago. Ground straps? I run 93 octane gas.

 

Yes


Yes ground straps. Ground the block to the chassis. Ask your local speed shop and do a search here on the forum.

 

Go intake, dp, and exhaust with pfc @ 12 psi (no tuning required) Judging from others' experiences on the forum, you should be at around 280-300 whp. Basically every power mod will noticably increase the feel and speed of your car.

Also, getting rid of your precat & stock exhaust will reduce probably 50lbs (estimate) off your car weight. Both those pieces (along with the main cat) are extremely heavy.

IMO, the downpipe should have been your first mod. If you're on a budget, you can probably just buy a k&n filter and gut the stock intake (search for that), and gut the precat. Note that a gutted precat will make less power gain than a straight downpipe. Precat isn't as aerodynamic and utilizes 2.5" pipe compared to a 3" dp.

Any estimate on how much hp the mustang is putting to the wheel?

 

I know what you're trying to say, but that's still funny...."pre-cat isn't aerodynamic"...LOL. Maybe a CF spoiler on it will improve its aerodynamics. J/K.

Get a downpipe and make sure to ceramic coat it to keep the temperature down in your engine bay. Ceramic coating also helps to keep the exhaust velocity up = exhaust gas exits faster = less back pressure on your turbine = faster spool (All in theory, but hell, ceramic coating just looks nice....so why not?)

 

I am kind of on a budget but getting a dp shouldn't be a problem for me. I can prob. get one next month. If the the pre-cat uses 2.5" piping how will that fit the 3" dp to the stock cat?

The guy with the mustang said that he puts down probably 290-300 hp. Wierd for a mustang with exhaust and intake.

 

my friends 99gt mustang with k&n intake, xpipe, exhaust, throttle body, intake plenum, pullies, diablo tuned chip, put down 253 whp on the dyno. I dunno about that one putting down 300. but then again i dunno, maybe my friend needed headers.

 

or maybe your freind said 300 hp, but not at the wheels

 

i dont see why its so fast

 

i asked wheel and he said 290-300 so i dont know

 

I looked on rx7store.net and it said that there are minor modifications that need to be done if i want to use the rx7store dp with the stock main cat, what modifications need to be done?

 

300 to the wheel seems like too much, probably 290-300 crank.

Downpipes are usually completely bolt on. The size of the piping has nothing to do with actual fitment because its the flanges at the end of the pipes that bolt against each other. If you run the dp with cb exhaust, they will both have 3" piping, while the stock cat will have 2.5" piping. So the cat will provide the most restriction, but its helpful in making sure you dont encounter boost creep/spikes. If its a low quality d/p it may not be a perfect fit against the catalic converter.

The hks style is complete bolt on to the manifold. If its the petit style, you will need to remove the studs as well as the bolts.

Are you planning on using a boost controller or engine management if you are going intake, dp, exhaust?

 

downpipe=good bang for the buck

 

Bah...he isn't putting 300hp to the wheels but a full exhaust GT should put it in mid 13s. So i guess you guys being close sounds about right. You probably need to work on your driving, you guys should be about even. Any idea of what exhaust he put on there?

 

he didnt put the exhaust on there he bought it that way and i dont know what kind it is.

So you guys say that there doesnt need to be any modifications to the dp to get it to fit to the stock cat but rx7store says that there is minor modifications that need to be done????

 

@ 12 psi with the mods described you should be @ 300 to the wheels. a friend of mine had 307 @ 13psi with minimum mods.

 

You may have to grind out a bolt hole or something minor. If you don't have the tools take it to a machine shop...Better yet ask Jason or Xavier at the RX-7 store what needs to be done and ask them to do for you before they ship it.

 

I have a drill to make a bolt hole, i'll also ask them if there needs to be anything else done.

 

No, DP is a direct bolt-on. Dont worry.

 

man you should kill that gt i use to destroy modded ones in my s2k i only lost to one with full bolts ons and gears but basic bolt ons there kinda slow, get a dp and you should kill him i dont get why your not beating on him now though!

 

all of these races were from a roll...right?

From a stop its a drivers race. GT's have lots or torque.

 

they were all from rolls. i figured i would beat him too but that thing is fast, he may have diff. gears in there, they are really tall, by the end of the quarter he is shifting into 3rd, im goin into 4th

 

have you figured out your ignition break up yet? If the car was running right, you shouldn't be having break up at stock boost and with just an intake.

Tim

 

Your car is very slow or something. I put about 8 cars on a GT at 10 PSI from a roll. GT with exhaust, intake, gears, and pullies. With my damn automatic!