broken DPI muffler heat sheild mount

[Jason]

Has anyone with a DPI exhaust had this happen...

33552

This is after about 2 years / 15k miles. No impacts or other abuse other than normal driving. I guess it needs welding to fix?

[Delorean Industries]

Had one fail on a ceramic coated system in Denver a while back. If you would like just send it in for warranty repair and or replacement if muffler body is torn.

[[email protected]]

I recently purchased DPI's muffler and a few days after I installed it I noticed it was making an unusual noise. On closer inspection I found that two of the heat shield mounting screws were missing so following a trip to the local hardware store for replacements I installed lock washers on all four of them. Several weeks later I discovered that the heat shield had folded outward in the middle but the mounting screws were still in place. I think it's all due mainly to the rapid thermal expansion and contraction taking place.

[Delorean Industries]

I recently purchased DPI's muffler and a few days after I installed it I noticed it was making an unusual noise. On closer inspection I found that two of the heat shield mounting screws were missing so following a trip to the local hardware store for replacements I installed lock washers on all four of them. Several weeks later I discovered that the heat shield had folded outward in the middle but the mounting screws were still in place. I think it's all due mainly to the rapid thermal expansion and contraction taking place.

Two things. If the fuel mixture is off the muffler will hold extra heat. Other thing is mounting hardware for the shield. Lock washers prevent it from expanding and contracting. The heat shield only comes with the hardware holding the shield in place but not tight. Usually the reason for hardware loss is due to not tightening during install.

[Delorean Industries]

And as always never hesitate to contact directly with questions or issues. Better than having to waste time finding it on here.

[[email protected]]

Josh, initially I only lost one of the bottom fasteners and after replacing it and checking that they all were tight I again lost the second one several days later. That's when I decided to install the lock washers. Since then no problems, except for the metal cease in the middle which doesn't bother me in the least. Don't know about the fuel mixture, seems to be running ok, knock on wood!

[Delorean Industries]

If the air fuel is over 16.8 to 1 the muffler temp can reach temps in excess off 250f over normal operating temps. I always set the co via a wide band as dwell is a joke.

[hmcelraft]

Wide band equipment is somewhat more reasonable these days but, even with the newer lower cost equipment, acquiring and getting a system set up for use is like using a sledge hammer to drive a nail. I would submit that a dwell setting for an OEM car is a pretty good approximation for the typical driver - not a joke. If one has a performance engine then high accuracy is, of course, more important.

[Delorean Industries]

Our exhaust system is specifically designed with a provision for this. A bung is placed in the exhaust stream in both headers allowing for the stock 1 wire lamdba to be installed on the drivers side and a wide band on the passenger. Wide band kits require less than five minutes to install on the SPEC I offering and can be plugged in when required to check the fuel mixture at any time leaving the lower sealed cable section in place.

The products are extremely affordable from name brands for around $150.00 with a digital gauge. If you can't afford to do it right you shouldn't be doing it at all. Reading dwell off a 30+ year old corroded junk to being with circuit to accurately set one of the most important perimeters on any engine is a bad idea. This stigma of good is good enough needs to be put to rest in regards to engine management on a DeLorean even with K jet. If this is truly the mind set of owners the SPEC I offering will include a wideband system as well.

[Bitsyncmaster]

The narrow band sensors work very well but are only useful at 14.7 AFR. Our unheated narrow band is marginal at idle speeds however.

That said, I am running a wideband in my DeLorean. It is driving the stock Lambda ECU and works very well doing that with the LC-1 wideband unit. I do have the ability to set it to run most any AFR and it is a heated sensor. I have also connected the unit to my netbook to get AFR plots while driving the car.

[Delorean Industries]

You are correct Dave that integrating it fully has added benefits. My minimum recommendation is to use this to set the single wire within the proper operating range. Just because the FV is buzzing doesn't mean it is optimal. Changing the combustion process marginally even by half a fuel point is a massive swing in exhaust temps.

[DMC5180]

Has anyone with a DPI exhaust had this happen...

33552

This is after about 2 years / 15k miles. No impacts or other abuse other than normal driving. I guess it needs welding to fix?

A more durable design improvement to this tab would be a two points of contact (hat section) welded support. It's always interesting to see what breaks under TIS conditions.

As a side note, the OEM design upper muffler bracket is one of those high failure components that would have likely have been redesigned had the company survived.

[Delorean Industries]

curious if this is one of the very early styles with the mounting tab welded on edge. Or if it is one of the full body z tabs like most. The change came after the one ceramic coated failure years ago.

[DMC5180]

Hmm, full body Z tab? Got photo? The broken tab does not appear to be a Z but does appear to look like a simple offset tab.

Resonant vibration can be quite fatiguing under curtain conditions.

[Delorean Industries]

Hmm, full body Z tab? Got photo? The broken tab does not appear to be a Z but does appear to look like a simple offset tab.

Resonant vibration can be quite fatiguing under curtain conditions.

I will take a picture when I'm back at the shop tomorrow. All of the ones on the site have the shield installed.

[[email protected]]

Ok guys, I need some schooling on this wide band device you're talking about. If it will allow me to more accurately set the air/fuel ratio than using a dwell meter, I want one. What do they look like and how do you use it?

[dmruschell]

Ok guys, I need some schooling on this wide band device you're talking about. If it will allow me to more accurately set the air/fuel ratio than using a dwell meter, I want one. What do they look like and how do you use it?

I'm curious, too. Considering all of my cars besides my DeLorean are carbureted, it would definitely be a worthwhile investment for me.

[opethmike]

They are a type of oxygen sensor. Here is the one I use for my EFI system:

http://www.diyautotune.com/catalog/innovate-mtxl-gauge-sensor-controller-3844-p-467.html

The gauge displays the air to fuel ratio. You can either install in a second oxygen sensor bung (you'd have to have one welded on), or in place of the existing O2 sensor, using the narrow band output wire.

So if using one to set the base air/fuel mixture on a DMC, you would take out the narrow band sensor, hook up the wideband sensor, and adjust the mixture until the wideband gauge displays the desired mixture.

[Bitsyncmaster]

They are a type of oxygen sensor. Here is the one I use for my EFI system:

http://www.diyautotune.com/catalog/innovate-mtxl-gauge-sensor-controller-3844-p-467.html

The gauge displays the air to fuel ratio. You can either install in a second oxygen sensor bung (you'd have to have one welded on), or in place of the existing O2 sensor, using the narrow band output wire.

So if using one to set the base air/fuel mixture on a DMC, you would take out the narrow band sensor, hook up the wideband sensor, and adjust the mixture until the wideband gauge displays the desired mixture.

If your still running the stock lambda system, you still should use the dwell meter to set the frequency valve to be running in the middle of it's range. A narrow band O2 sensor (stock unit) can only work at 14.7 AFR. If you have a wideband readout it should be reading 14.7 AFR with the dwell running from 15 to 80 degrees of dwell reading. Going beyond that dwell setting and your running open loop.

If your running open loop (no lambda ECU) then you just set the mixture you want via the displayed read out.

A wideband sensor uses it's own ECU to drive the wideband sensor and provide a readout or voltage output. You cannot just install the sensor itself. They normally have 5 wires to control it.

[DMC5180]

This thread has derailed from the OT and should be split.

I'm admittedly uninformed on this wide band system integration into the Delorean. How or where are those 5 wires connected? If you have the second O2 port (per the spec I system) and running the wide band, is the OE system disabled? Which system is driving the FV?

[Delorean Industries]

A lot of misinformation here. The intent for most owners is installing the wide band as a device purely for the purpose of setting the stock FV within the appropriate operating range. Not to outright control the system within the operating range. The frequency valves dwell can hang within a wide range and that entire range is not 14.7 stoich. Or anywhere close for that matter. 20-80 is not the range you want to shoot for. 29-38 is. If you are swinging that far back and forth other problems are present ranging from 02 sensor age to grounding problems with the ecu.

I will start posting all of this information directly with our products for owners to refer to as this forum, others like it and social media successfully misinform owners on how to install and utilize our product offerings to the fullest.

[[email protected]]

So I purchase a wide band sensor and install it in the second bungie on the exhaust and adjust the mixture until I get it somewhere between 29 and 38?

[opethmike]

Yeesh, Josh woke up on the wrong side of the bed today. Crabby crabby.

[Delorean Industries]

Physically impossible Mike.... I put the wrong side up again the wall. Every day starts out cherry.