ben0711

hey everyone,
ive just brought my first RX7 2.6 tt, i wanted to replace my factory intercooler for a hks intercooler but wasn't sure if once i put it on i will have to re-tune the engine or alter anything else? any help would be great,

thanks

ben

rynberg

Depending on other mods, you may need a boost controller (manual or electronic) to maintain 10 psi of boost. The aftermarket IC will have less pressure drop than the stock IC, potentially resulting in higher boost levels.

Mahjik

iTrader: (1)

You only need to deal with ECU issues when you increase boost levels. Having said that, adding an aftermarket IC can allow you to make more than stock boost levels (as the turbos won't have to work as hard to produce the same boost at the manifold).

It should be fine to change out the stock IC, just keep an eye on the boost to make sure it does not increase.

ben0711

ok this may sound stupic but how do i keep an eye on the boost?

ben0711

and ive already got a straight through decat pipe n 4" blitz exhaust and HKS air filters? as long as its not gonna mess my engine up, thats all im conserned about.
cheers guys for ya help, im a noob when it comes to engines, my last car was a 1.1 ltr saxo lol.

Mahjik

iTrader: (1)

You need to purchase and install a boost gauge. There are a few gauges people usually recommend for these cars, one of them being a boost gauge. This will let you know whether or not your turbo system is working properly or not, as well as give you information for troubleshooting should you develop a problem with the turbo control system.

VegasFD

Umm, a boost gauge?

rynberg

You've already got a midpipe? You are at SERIOUS risk of blowing your motor! Do NOT get on the car until you've installed a boost gauge. Put the main cat back on.

ben0711

what good will that do puttin a guage on if i have a mid pipe? i will get a boost gauge this weekend. hks alright yeah ?

VegasFD

The boost gauge guage will not prevent boost spike/creep, but it will allow you monitor whether or not (and how severely) the the spike/creep is. Which is the first step to fixing it.

tiger18

iTrader: (1)

Ben0711,,, holy moly you jumped from a 1.1 saxo to an RX7 i bet that was a shock increase in power LOL!.

ben0711

so you recon the it will be over boostin because of the straight through? but yeah thanks all that helped n ill let u know how i go when i get the gauges. thanks everyone

o and is there any website that you can listen n see different exhausts, i want a new exhaust but not sure what sound im after n i looked on here n i couldn't open hardly any of the links to listen to the exhausts.

cheers ben

ben0711

yeah n its crazy ! lol . n im only 21 so im payin out the *** for insurence !

tiger18

iTrader: (1)

basically what the guys above are saying is without no main cat and a total free flowing exaust the turbos tend to spool very fast (very little back pressure in the exaust system),,, so when you buy a boost gauge you will notice the boost build up very fast and go shooting past the factory set 10psi (the stadard ECU is not set up to run above 10psi,,,so the mixture will run lean, the engine will detonate and basically knacker up).

tiger18

iTrader: (1)

(by the way is your rx7 an import and which insuracne company you using???)

ben0711

yeah its a import and im with dial direct, i found it on autotrader.co.uk.

ben0711

so how do i then go about changing it back to 10 psi??? or should i take it to someone?

Mahjik

iTrader: (1)

Did you buy the car with the exhaust modifications done or did you do them after getting the car?

ben0711

i brought it with with the exhaust with all the mods already done (the filters n exhaust) so i wanted to carry on with the mods with the intercooler. will a intercooler change the sound of my car at all?

so im not too sure if the previous owner would have had something done to combat puttin the exhaust system on?. he did have all the work done at a garage that specializes in rx7/8's. so do u recon they would have made sure everything was alright?

im gonna take my car in this saturday to get the boost gauge put on.

Mahjik

iTrader: (1)

You might check to see what the ECU looks like. Its possible, you already have an upgraded ECU in the car or its possible that the previous owner made sure the boost was contained.

Its also possible that the previous owner had an aftermarket ECU on the car but sold it separately (as you can typically make more money that way).

You won't know until you start checking things out.

ben0711

im not sure, ill have them have a look on saturday. so if my cars over boosting then ill need a aftermarket ecu? is there anything else ill need? you lot really know your stuff !fair play!
thanks everyone !

Unxpected

Don't mean to hijack your thread or anything, but..

One quick question here. If, I were to upgrade a stock Rx-7 3'rd Gen. With 3' exhaust, down pipes, different intercoolers, air filters, boost controller; would I need to get a retune, if I used the boost controller to limit the boost pressure levels to 10 Psi..?

Mahjik

iTrader: (1)

If your boost is out of control, you should get a boost controller and/or add some restriction in the exhaust like a restriction plate to be able to control the boost. Out of control boost comes from two types generally:

Boost spikes
Boost creep

Spikes are just quick spikes in your boost pattern. They generally happen on the initial surges of boost (like the first turbo hitting or when both turbos hit). Basically, the stock system cannot react fast enough. Electronic boost controllers are great for this situation.

Creep is where the boost will continually increase. Its not a quick spike and then back down to normal levels. This is from the fact that there is too much exhaust flow. There are a few things to do here on this one:

* port the wastegate
* install a restriction plate in the exhaust line

Porting the wastegate allow the wastegate to handle more flow. Basically, the wastegate is being overrun in this situation. However, in some cases, this did not completely rid the car of boost creep.

Restrictor plates are basically gaskets. They go between the pipe connections and are a smaller diameter than the piping. So, if you have a 3 inch diameter exhaust pipe, the restrictor plate might be 2.5 inches. The goal is to find the right size to be able to control the boost so the actual restrictor size may vary from car to car.

Once you have the boost under control and you want the ability to raise the boost from time to time, then you should look into ECU upgrades (if your car doesn't already have one).




The stock ECU has been proven to be able to support full-on's at 10 PSI. However, the problem comes in to keeping the boost at 10 PSI with an open exhaust.

RE-Amemiya

I jumped from a Geo Prizm to an FD, no big deal.

Of course i had a BMW and a Mustang as well.

tiger18

iTrader: (1)

lol hes probably been driving his front wheel drive 40BHP saxo for a few years then jumped to 300BHP rear wheel RX7,,, can be a nice handfull in the wrong hands.