It's been a while since I posted here. I have been away from RX7's for a while. I took on a project for a friend. He wanted me to replace the turbo in his 87 TII with 46k original miles. He is the original owner. He was going to send it away to rebuild. After removing the turbo (looked and felt fine), he sent it to BNR and had a Stage 1 Turbo returned to him.

I am not a person who can tune a modified car, I am strictly stock with my knowledge. I know there used to be a section on reliability mods and minimum requred to prevent the engine from blowing apex seals. I cannot find it now.

Here is my question. What is the probability of causing damage to the motor? My friend was just going to drive this car home. I am in PA and the temp ouside is around 32 degrees. His car currently has a stock unmolested motor. I installed the BNR stage 1 clipped modified stock turbo. I also installed a SS downpipe and resonator from Racing Beat. He also has an aftermarket SS exhaust from that point back.

He has NO aftermarket boost gauge, boost controller, fuel pressure regualtor, or modifed ecu, AFC, AEM, etc. It is just stock.

My gut feeling is that he will drive this home and blow the engine up as he starts climbing a hill. I think that the boost will spike and/or go lean without having any means to control it and blow the motor, even if he takes it easy on the throttle.

Can anyone chime in that has any factual knowledge or experience. I finished the car up today and he wants to pick it up, but he has to drive it 50 miles over several mountains to get it back home. Also, he wants to drive it around for a few weeks until he can install an AFC (still has not purchased yet). He then was going to take it down to KD Rotary to have him tune it up.

Am I right or wrong?? Any help would be greatly appreciated.

PS MODERATORS, hopefully this is in the right section. If not, please move it to the correct area.

Thanks in advance!!
Tim McCreary

 

I think his drive home will be fine, just emphasize on him keeping a light foot for the most part. On a stock ecu, its more of a ticking time bomb than an instant blow. I havent had any experience with RTek but, I hear it works well on mild-moderate set ups..something to look into.

 

Very little chance if he is easy on it.. Pull about 8 degrees off the timing, run a higher octane fuel and I am sure he will be fine.

 

It will be fine. Tell him to drive it easy and run premium gas for sure.

 

as long as he isnt gunning it up the hill, it should be fine. Though, when going up them PA hills, you do need some momentum. If anything, he will hit fuel cut once boost goes 7-8psi before any damage can occur.

 

I would think your friend would need a fuel cut defencer (FCD), or some call it a fuel cut controller.

His best bet would be to go with a standalone and a good tune... Not an AFC.

 

BNR ports their turbo wastegates very nicely. Especially the S4.

So I think your boost won't be spiking as much as with the factory unit.

Why can't you just unhook the wastegate actuator arm and lock it open?
No boost, or a negligible amount, and the drive home will be totally safe for the motor.

Also, Brian at BNR recommended Rtek 1.8 when I bought my stage one.
Personally I think the Rtek would take care of your friend until he decides to go with a standalone.

Also they sell pretty quickly around here too.

 

Because if you disconnect the waste gate you will over spool your turbo and ruin a perfectly good turbo.

 

Thanks for all the advice!!!! I know that my experience is mainly with the 3rd gen turbos and the boost is at 10psi to start. I know that a slight boost spike can blow those motors quickly.

 

How do you figure?

Propping the wastegate open diverts exhaust gas AWAY from the turbo's turbine or "hot side"

No/little exhaust pressure = no boost = incredibly slow rotation.


I'm not talking about removing the vacuum line. I said disconnect the actuator arm and use something to hold it open.

 

I think you may have mis-read what was suggested. Locking the WG open will cause little to no boost..

 

Was just my $.02

If you're unsure of how much boost it will make throughout the power band,
why not just take it out of the picture and drive it home rather slowly but safely.

 

+5. it'll run like a n/a car... no worry about earlier boosting with the stage1 setup... might as well do that and not worry.

rtek 1.7 with 720cc secondaries. safc... and away you go. it'll get the job done.. just not nearly the same results as a full standalone... which i highly recommend.