Interesting thought about the VH45DE

[elwesso]

So this evening I was talking to another unidentified Q owner, and an interesting thought came to mind..

As we know, the main differences between the 90-93 VH45 and 94-95 VH45 are as follows

- Guides from the factory- Sodium filled valves- Injectors- Heads- intake runners- various wiring- other random things

So I was thinking... What IF someone took a 94 engine and simply swapped in the sodium filled valves... To me, that is really the only major difference where the 94 engine got worse... that HAS to be where the alleged extra HP remains (I still think most of it is in that 1st gear and the ECU tuning)... Heres some things we KNOW..

The short block is the same for the most part, meaning pistons, rods and stuff was not changed, meaning it uses the same CR.... The only major differences were in the long block (mechanically), using the different heads for RTV valve covers, siamesed intake ports, and so on...

It almost seems too obvious... the 94 and later engines are just better overall it seems because of the more reliable injectors, the non siamesed ports (better for boost?), metal guides from the factory, better wiring, uses valve cover gaskets instead of RTV, and continues to boast similar reliability with Jamesmost's stock 95 engine lasting well over 300k with the absolute tar driven out of it.

To me it seems like the easy way to make the so called "ultimate VH45" still using all factory parts... the question is if the sodium valves will go into the 94 heads...

[Ezekial]

So this evening I was talking to another unidentified Q owner, and an interesting thought came to mind..

As we know, the main differences between the 90-93 VH45 and 94-95 VH45 are as follows

- Guides from the factory- Sodium filled valves- Injectors- Heads- intake runners- various wiring- other random things

So I was thinking... What IF someone took a 94 engine and simply swapped in the sodium filled valves... To me, that is really the only major difference where the 94 engine got worse... that HAS to be where the alleged extra HP remains (I still think most of it is in that 1st gear and the ECU tuning)... Heres some things we KNOW..

The short block is the same for the most part, meaning pistons, rods and stuff was not changed, meaning it uses the same CR.... The only major differences were in the long block (mechanically), using the different heads for RTV valve covers, siamesed intake ports, and so on...

It almost seems too obvious... the 94 and later engines are just better overall it seems because of the more reliable injectors, the non siamesed ports (better for boost?), metal guides from the factory, better wiring, uses valve cover gaskets instead of RTV, and continues to boast similar reliability with Jamesmost's stock 95 engine lasting well over 300k with the absolute tar driven out of it.

To me it seems like the easy way to make the so called "ultimate VH45" still using all factory parts... the question is if the sodium valves will go into the 94 heads...

or better yet, run the 94 model engine with some new stainless valves

why is a rocker cover gasket better than RTV? I hate gaskets! The best thing about the VH45 engine is barely no gaskets!!

[Jeff Williams]

Just refil that Nitrous bottle, and call it a day.

[nchopp]

Just refil that Nitrous bottle, and call it a day.

[Flagship-Q]

I was under the impression that the 90-93 heads flowed better than the later models. If that was the case, then wouldn't that be a step backwards to go with 94 heads? Just a thought.

[defrag010]

Siamesed intake ports will create an air flow restriction on the junction where the two ports split. When you port a head with 2 intake valves per cylinder, you focus on this part the most so you can make it as sharp as possible.If you want to boost the motor, you don't need to take this into consideration as much as you do overall intake runner size and shape.

Sodium valves offer no immediate horsepower gains. Where they benefit from is better heat rejection, which basically means more longetivity due to less heat transfer from the valve to the seat. They have the same affect as stainless valves.

If I were going to build me up a set of VH heads I would press in some new seat inserts, find some 1mm oversize stainless valves, blend the bowls, and teardrop the guide boss along with hogging out the intake runners for more port volume and less restriction from the junction split. Oh, can't forget to shim the valvesprings for a little more pressure and a set of mild cams.

[Jesda]

The biggest difference is in weight. The 94 Q45 is a fantastic long-distance touring car, thanks in part to extra sound deadening and more luxury features. At 3800 lbs, the 90-93 Q without active or TCS is as light as the Q gets without turning into a spartan econobox.

I definitely prefer RTV over gaskets. My last Q at 210k never had the valve covers done, and didnt need them. GM favors cork gaskets. Spend a few moments at the Cadillac forum to see why RTV is better.

Now, it would be nice to get those 94 injectors into a 90-93.

[Q45tech]

The siamesed ports are easier to tune for fuel reversion. Notice the bump in lower port path..........really tricky to create every ounce much less a full lb/ft at 1600 rpm lugging up a small hill in 100F ambient with AC on and a full load of Sumo bodyguards.

Redesigning for an extra presurized flow would obviously require some changes in the head.

[RobertsnewQ]

Jesda - someone on the forum is doing/did the 94 injector swap. You need the rails, at least...

[Jesda]

[QUOTE=RobertsnewQ]Jesda - someone on the forum is doing/did the 94 injector swap. You need the rails, at least...[/QUOTE

Now THAT is interesting.

[PopPop]

Does anyone have the flow numbers on any Q45 Stock factory heads? If so I would like to see what the Bench Flow showed! Flow numbers on heads that have been re-worked would be nice also! I would also like to see some or any Dyno numbers if any members have could someone please post!

[RYANW501]

are the pistons and rods the same for the 91 and 94.. and if so does anyone want to donate a rod and piston for my vh swap?