What's the best way to get the car running at maximum boost and know you're not detting?

 

I've seen a detonation warning gauge on a site somewhere and wondered if these are any good?

Am I better getting an exhaust gas temp meter instead?

I've got a boost controller so safety boost is mostly bypassed.

 

Had one engine die from possible detonation at high revs and don't want it happening again... :(

I think if you use boost jets the safty boost will activate.

 

Some one made a circut which makes the hazard warning light come on when safty boost is activated. This works with boost controlers too, but the boost wont come down, just the light will come on.

 

Stuart

Yep, that's on Maciej's site - http://home.swipnet.se/e-solutions/SB-ind.html

 

I got one made up and it works.

 

Vijay

Unfortunately it won't work!!

 

The stock det sensor does not detect detonation above 3000rpm, there is a device that does but costs 370ish the guys on the rx7 forum have had some success with this!

 

The only practical option is to get two egts gauges with warning lights for a temp above 900

 

Mark

Hello Mark,

 

I meant it tells when it's in safety boost...........................

 

I thought the aftermarket det meters still used the stock det sensor too.

 

Vijay

Mark, from:

 

http://www.streetrodstuff.com/Articles/September_2000/Engine_Basics_I.php

 

"The other technique is a little more subtle but usable if attention is paid to EGT (Exhaust Gas Temperature). Detonation will actually cause EGTs to drop. This behavior has fooled a lot of people because they will watch the EGT and think that it is in a low enough range to be safe, the only reason it is low is because the engine is detonating"

 

-Andrew

couldnt you buy an air/fuel ratio meter, it wont tell you if your detting but atleast it will tell you if you are running lean

Thanks Andrew, that's an interesting read.

 

So basically there's not much way of telling if it's happening other than watching the stock detonation sensor at low revs and keeping the boost below a level that it starts?

 

I would have thought though that it's still possible to get detonation at high revs flat out (which is when mine died) when it was showing no signs at lower revs?

 

Only problem is the amount of boost you can use varies massively from day to day with atmospheric pressure, air temperature and type of fuel...

It can also run high on EGT's as well, indicating that the engine is not running correctly!

 

If we are to believe what we are told, then EGT's can give an indication of detonation/preignition, if you get a more precise logging device then you can record your engines performance!

You can keep a log of it and monitor differences in engine parameters!

 

The EGT can also give an indication that you are running with correct fueling so potentially having a dual purpose!

 

The detonation sensor device I believe uses its own detonation sensor, I know very little about it! I have a done a search on the RX7 forum and it is called a J&S knock sensor, I think it is expensive!

 

http://www.jandssafeguard.com/products.html

 

Mark

Could use water injection, i had a kit but sold it, they lower the burn temps dramatically and atleast it would give you a "safety barrier".

Potentially can give you a few more ponies with its cooling of intake effect too.

 

http://www.aquamist.co.uk

At the end of the day Chris you were unlucky, How many people have you heard of on the forum that have destroyed a con rod!

 

All you have to do is get some forged pistons if you want to be extra careful, and set your car up on a proven setup!

Depending on how much driveability, bhp you want and how much of a budget you have!

 

Talking of budgets I had better shut up!

 

LOL

 

Mark