We are pleased to announce our newest product, the DTT EGR Turbo Back Pressure adapter plate.





This plate mounts between your intake manifold and EGR valve (or blockoff plate) to allow the user to monitor the exhaust back pressure between the cylinder head and the turbo. It allows 100% full operation of the EGR system. This adapter plate also works on '90-'99 4g63 turbo DSM's. The plate can be mounted in two orientations to accommodate most setups.

Excessively high back pressure can adversely affect the engines VE (volumetric efficiency) which can rob optimal performance. With the use of this back pressure plate, you can find the optimal boost level to run on your current setup without VE losses.

High back pressure ratios can also lead to premature turbo failures, especially on large T3 turbos or stock frame turbos limited to an OEM exhaust housing at higher boost levels.

To calculate your exhaust back pressure ratio use the following formula:

exhaust back pressure/intake manifold pressure= back pressure ratio

EXAMPLE:

30 psi intake manifold pressure
41 psi exhaust back pressure

41/30= 1.36:1

Ideally, you don't want to exceed a back pressure ratio of 1:1 but thats not always possible or necessary with certain setups. Here is a small chart that WE feel is a good starting point when monitoring back pressure:

1.0:1 IDEAL
1.0:1-1.3:1 Still very acceptable
1.4:1-1.6:1 Start looking into options to improve back pressure or lower boost levels
1.7:1-2.0:1 Reaching levels that can prematurely shorten the life of the turbo.
2.0:1 and up Dangerously high levels. Turbos will begin to hate you.


Our back pressure plate design incorporates a restrictor which minimizes boost fluctuations caused by the cylinders exhaust pulse reversion. This ensures a smooth boost curve when datalogging or viewing on a boost gauge.

Included with the back pressure plate are an OEM EGR valve gasket, 1/8NPT 90 degree 1/4" hose barb and extendeded stainless steel mounting bolts for use with an OEM EGR valve.

*Note: due to variances in EGR blockoof plate designs, additional bolts are not included for blockoff plate users.

PRICE: $55.00 shipped to lower 48



PM us to order or call (508)336-DYNO

 

Here is a really quick example from an aftermarket stock frame turbo evo showing the back pressure. This was 2 consecutive pulls with the dyno's boost line switched between the intake manifold and then the back pressure plate to give us an overlay.

You will notice that the power tends to level off as the back pressure rises above a 1:1 ratio, which is to be expected to a degree. The blue/red WHP numbers just indicate the power level changes from one rpm point to the next.

 

The first 10 orders with free shipping have been fulfilled but we are extending the offer for the next 10! PM us to order.

 

Interesting product!

 

Excellent idea guys!

 

Thanks guys! So far people have really liked the product

 

Never thought to pick up a pressure reading there. Very nice!

 

Thanks! The nice thing about pressure is it fills up space evenly. So there really is no delay in pressure readings anywhere between the head and turbine wheel. Especially with how large the EGR passage is through the head.

The nice benefit is the distance allows for enough heat dissipation to not require a long piece 1/4" copper tube as a heatsink element like is required directly off the exhaust manifold. I could touch the fitting immediately after each pull.

 

Does it come with a plug for when your not logging?

 

The plate only comes with what is shown in the first picture in Post#1. You can use a standard vacuum nipple available at any local parts store though. We actually run a 12" length of vacuum line and attached a 1/4"-to-1/4" hose barb adapter on the end so it was more accessible in the engine bay. We just attached the nipple to the end of the 1/4"-to-1/4" hose barb adapter when we weren't using it.

It's quite handy to periodically check your back pressure if you are still running a catalytic converter too. As they begin to clog, the back pressure will climb rather fast.

 

Is it possible the reading at the EGR is not the same as measuring before the turbocharger? When I get my new setup going I would be happy to verify as I am logging pressure/EGT right before the turbocharger.

 

There should be no measurable difference whether back pressure is logged in the manifold or at the EGR with our back pressure plate. Pressure will fill a cavity equally as long as there are no large restrictions causing a delay. Think about how small the diameter is on the white nylon tubing that is supplied with their boost gauges. The EGR passage going through the cylinder head is about a half inch in diameter and poses no significant restriction or delay. Although the EGR passage through the water cooled, aluminum cylinder head does an amazing job of lowering the exhaust gas temperatures naturally to keep from damaging MAP sensors.

In order to view a smooth boost curve from the exhaust flow you need a restrictor in the system between the exhaust flow and the sensor to help counteract the pulse reversion caused by the multiple cylinders. Our back pressure plate has this restrictor built-in by design so there shouldn't be any need for MAP filtering or the burden of watching a boost gauge needle bounce around erratically.

 

That's a nice little bolt-on, and cheaper for most than welding a bung onto the EGR valve.

I think what you really see is that cylinder filling = torque. If you flip your expression of pressure ratio -> [boost/backpressure] it makes a bit more sense where >1 is goodness. Running over a value of one ensures a good clean intake charge cycle, where less than one means you can't push all the exhaust out and breathing suffers.

All that makes the following more or less true:
Load = (boost * (boost/backpressure)) * VE(rpm)

Can you post the logs from these runs?

 

I understand what you mean about trying to use the ratio in a manner to show a difference in load but it wouldn't necessarily work out mathematically I think . Like you said, less back pressure than intake manifold pressure ensures the engines VE is working at its optimal potential without any post-engine restrictions. In theory, if there was much less back pressure than intake pressure, it would almost imply that more air is flowing through the engine than the maximum VE, even though that may not be actually happening. I could be wrong though. Was that a proven mathematical formula you have found of just something that seemed to make sense that you were thinking about? I wouldn't mind exploring that further.

Either way that people use the ratio, it still shows the imbalance they are trying to monitor so it will be helpful either way they decide to use the ratio I suppose.

 

weekend bump!